| HPR | High Pressure Research | In English | → Serial publications, periodicals → Physics → Chemistry |
| HPSL | High Performance Smart Lid | In English | → Biological sciences |
| HQE | Haute Qualité Environnementale | In French | → Quality management → Nature and society → Environmental technology, water supply, waste management |
| HR | Homologous Recombination | In English | → Genetics |
| HR | Heat-Resistant | In English | → Thermodynamics |
| HR&T | Heat Rejection and Transport | In English | → Thermodynamics |
| HRSC | High Resolution Stereo Camera | In English | → Astronomy → Spaceflight engineering, astronautics |
| HRSO | High-Resolution Solar Observatory | In English | → Observatories |
| HRTEM | High Resolution Transmission Electron Microscopy | In English | → Physics |
| HS | Hydrogen Sulfide | In English | → Chemistry → Chemical technology |
| HS | Heat Shield | In English | → Thermodynamics |
| HS | History of Science | In English | → History |
| HSA | Heat Shield Abort | In English | → Thermodynamics |
| HSA | Health Science Authority | In English | → Medicine → Biological sciences |
| HSB | Heat Shield Boost | In English | → Thermodynamics |
| HSL | Hormonsensitive Lipase | In English | → Enzymes |
| HSPBS | Historical Studies in the Physical and Biological Sciences | In English | → Serial publications, periodicals → Physics → Biological sciences → History |
| HSS | History of Science Society | In English | → Organizations and associations → History |
| HST | Hubble Space Telescope | In English | → Astronomy → Spaceflight engineering, astronautics |
| HT | Heat Treatment | In English | → Thermodynamics |
| HT | Heat Transfer | In English | → Thermodynamics |
| HT | Hadamard Transform | In English | → Mathematics |
| HTD | Human Transcript Database | In English | → Genetics |
| HTemS | High Temperature Science | In English | → Serial publications, periodicals → Physics → Chemistry |
| HTHP | High Temperatures and High Pressures | In English | → Serial publications, periodicals → Physics → Chemistry |
| HTJR | Heat Transfer Japanese Research | In English | → Serial publications, periodicals → Thermodynamics |
| HTPB | Hydroxyl Terminator Polybutadiene | In English | → Physics → Chemical technology |
| HTPB | Hydroxyl Terminated Polybutylene | In English | → Physics → Chemical technology |
| HTrEn | Heat Transfer Engineering | In English | → Serial publications, periodicals → Thermodynamics → Engineering, technology |
| HTS | Heat Transport Section | In English | → Thermodynamics |
| HTSR | Heat Transfer Soviet Research | In English | → Serial publications, periodicals → Thermodynamics |
| HUT | Hopkins Ultraviolet Telescope | In English | → Astronomy |
| HUVEC | Human Umbilical Vascular Endothelial Cell | In English | → Biological sciences → Medicine |
| HvaOB | Hvar Observatory Bulletin | In English | → Serial publications, periodicals → Astronomy |
| HWP | Horizons in World Physics | In English | → Serial publications, periodicals → Physics |
| HydJ | Hydrogeology Journal | In English | → Serial publications, periodicals → Hydrology |
| HyInt | Hyperfine Interactions | In English | → Serial publications, periodicals → Astronomy → Physics |
| HyPr | Hydrological Processes | In English | → Serial publications, periodicals → Hydrology |
| I | Isoleucina = I | Isoleucine | In English = I | Isoleucina | In Catalan = I | Isoleucin | In Danish = I | Isoleucin | In German = I | Isoleucina | In Spanish = I | Izoleŭcino | In Esperanto = I | Isoleucine | In French = I | 이소류신 | In Korean = I | Izoleucin | In Croatian = I | Isoleusin | In Indonesian = I | Isoleucina | In Italian = I | איזולאוצין | In Hebrew = I | Izoleicīns | In Latvian = I | Isoleucin | In Letzeburgesh = I | Izoleucinas | In Lithuanian = I | Isoleucine | In Dutch = I | イソロイシン | In Japanese = I | Izoleucyna | In Polish = I | Изолейцин | In Russian = I | Isoleusiini | In Finnish = I | Isoleucin | In Swedish = I | İzolösin | In Turkish = I | Ізолейцин | In Ukrainian = I | 異亮氨酸 | In Chinese |
In Portuguese | → Biochemistry, biophysics |
| I | イソロイシン = (look above) |
In Japanese | → Biochemistry, biophysics |
| I | Isoleucine = (look above) |
In Dutch | → Biochemistry, biophysics |
| I | Isoleucine = (look above) |
In English | → Biochemistry, biophysics |
| I | Izoleucinas = (look above) |
In Lithuanian | → Biochemistry, biophysics |
| I | Изолейцин = (look above) |
In Russian | → Biochemistry, biophysics |
| I | Isoleusiini = (look above) |
In Finnish | → Biochemistry, biophysics |
| I | Isoleucin = (look above) |
In Swedish | → Biochemistry, biophysics |
| I | İzolösin = (look above) |
In Turkish | → Biochemistry, biophysics |
| I | Ізолейцин = (look above) |
In Ukrainian | → Biochemistry, biophysics |
| I | 異亮氨酸 = (look above) |
In Chinese | → Biochemistry, biophysics |
| I | Isoleucina = (look above) |
In Spanish | → Biochemistry, biophysics |
| I | Isoleucin = (look above) |
In Letzeburgesh | → Biochemistry, biophysics |
| I | Izoleicīns = (look above) |
In Latvian | → Biochemistry, biophysics |
| I | איזולאוצין = (look above) |
In Hebrew | → Biochemistry, biophysics |
| I | Isoleucina = (look above) |
In Catalan | → Biochemistry, biophysics |
| I | Isoleucin = (look above) |
In Danish | → Biochemistry, biophysics |
| I | Isoleucin = (look above) |
In German | → Biochemistry, biophysics |
| I | Izoleŭcino = (look above) |
In Esperanto | → Biochemistry, biophysics |
| I | Isoleucine = (look above) |
In French | → Biochemistry, biophysics |
| I | Isoleucina = (look above) |
In Italian | → Biochemistry, biophysics |
| I | 이소류신 = (look above) |
In Korean | → Biochemistry, biophysics |
| I | Izoleucyna = (look above) |
In Polish | → Biochemistry, biophysics |
| I | Izoleucin = (look above) |
In Croatian | → Biochemistry, biophysics |
| I | Isoleusin = (look above) |
In Indonesian | → Biochemistry, biophysics |
| I | Inosine | In English | → Genetics → Biochemistry, biophysics |
| IAA | International Aerospace Abstracts | In English | → Serial publications, periodicals → Astronomy → Aeronautics, aircraft → 6297 |
| IABEM | International Association for Boundary Element Methods | In English | → Associations → Mathematics |
| IACNDR | Inter-American Committee on Natural Disaster Reduction = CIRDN | Comité Interamericano para la Reducción de los Desastres Naturales | In Spanish = CIRDN | Comitê Interamericano sobre a Redução de Desastres Naturais | In Portuguese |
In English | → Organizations and associations → Natural disasters |
| IACR | International Association for Cryptologic Research (www.iacr.org) | In English | → Associations → Mathematics → Telecommunications |
| IAdEM | Internacia Asocio de Esperantistaj Matematikistoj | In Esperanto | → Associations → Mathematics |
| IadEN | ядерная энергия = IadEn | Iadernaia Energiia | In Russian |
In Russian | → Serial publications, periodicals → Nuclear, atomic, and molecular physics → Nuclear technology |
| IadEn | Iadernaia Energiia = IadEN (look above) |
In Russian | → Serial publications, periodicals → Nuclear, atomic, and molecular physics → Nuclear technology |
| IAF | Institut für Angewandte Festkörperphysik | In German | → Physics |
| IAFE | Instituto de Astronomía y Física del Espacio | In Spanish | → Astronomy |
| IAGC | Institute of Applied Genetics and Cell Biology = IAGZ | Institut für Angewandte Genetik und Zellbiologie | In German |
In English | → Research institutes → Genetics → Cytology |
| IAGZ | Institut für Angewandte Genetik und Zellbiologie = IAGC (look above) |
In German | → Research institutes → Genetics → Cytology |
| IAH | International Association of Hydrogeologists | In English | → Associations → 5325 → Hydrology |
| IAIN | International Association of the Navigation Institutes | In English | → Associations → Geodesy, cartography → Vehicle engineering |
| IAL | International Algebraic Language | In English | → Mathematics |
| IAL | International Association for Lichenology | In English | → Organizations and associations → Botany |
| IAP | Institut für Allgemeine Physik | In German | → Physics |
| IAPPP | International Amateur-Professional Photoelectric Photometry Communications | In English | → Serial publications, periodicals → Physics |
| IAPS | International Association for People-environment Studies | In English | → Associations → Nature and society |
| IAPS | International Association of Physics Students | In English | → Associations → Education → Physics |
| IAS | Islamic Academy of Sciences | In English | → Academies → Islam |
| IAS | Indian Academy of Science | In English | → Serial publications, periodicals → Academies |
| IASI | Infrared Atmospheric Sounding Interferometer | In English | → Meteorology, climatology |
| IASP | International Association of Science Parks | In English | → Associations → Museums |
| IASPEI | International Association of Sesimology ans Physics of Earth Interior (www.iaspei.org) | In English | → Research institutes → Geophysics → Seismology, earthquakes |
| IAU | International Astronomical Union | In English | → Organizations and associations → Astronomy |
| IAUC | International Astronomical Union Circular | In English | → Serial publications, periodicals → Astronomy |
| IAUT | Transactions of the International Astronomical Union | In English | → Serial publications, periodicals → Astronomy |
| IAVCEI | International Association of Volcanology and Chemistry of the Earth's Interior (www.iavcei.org) | In English | → Associations → 55121 → Geochemistry |
| IBA | Institute for Biomedical Aging Research | In English | → Research institutes → Biological sciences → Medicine |
| IBBA | Istituto di Biologia e Biotecnologia Agraria: Sezione di Pisa | In Italian | → Biological sciences → Biotechnology |
| IBEB | Instituto de Biofísica e Engenharia Biomédica | In Portuguese | → Biochemistry, biophysics → Biotechnology → Medicine |
| IBF | Istituto di Biofisica | In Italian | → Biochemistry, biophysics |
| IBICT | Instituto Brasileiro de Informação em Ciência e Tecnologia | In Portuguese | → Applied sciences, technology |
| IBISC | Informatique, Biologie Intégrative et Systèmes Complexes | In French | → Computer science → Biological sciences |
| IBL | Institut de Biologie de Lille | In French | → Research institutes → Biological sciences |
| IBN | Institut für Biophysik und Nanosystemforschung | In German | → Biochemistry, biophysics → Biotechnology |
| IBR | Institut für Biophysik und Röntgenstrukturforschung | In German | → Biological sciences → Biochemistry, biophysics |
| IBS | Institut de Biologie Structurale | In French | → Biochemistry, biophysics |
| IBSH | Informational Bulletin of the Southern Hemisphere | In English | → Serial publications, periodicals → Earth sciences |
| IBT | Internationaler Bund der Tierversuchsgegner (www.tierversuchsgegner.at) | In German | → Organizations and associations → Nature → Pharmacology, toxicology |
| IBVS | Informational Bulletin on Variable Stars | In English | → Serial publications, periodicals → Astronomy |
| ICA | Independent Component Analysis | In English | → Mathematics |
| ICA | Institut de Chimie de Annaba | In French | → Specialized or (poly)technical colleges → Chemical technology → Chemistry |
| ICAM | Intercellular Adhesion Molecule | In English | → Biochemistry, biophysics |
| ICAP | International Conference on Atomic Physics | In English | → Congresses → 53198 |
| ICBP | Institutul de Biologie si Patologie Celulara | In Romanian | → Biological sciences |
| ICCAT | International Commission for the Conservation of Atlantic Tunas (www.iccat.es) | In English | → Nature → Fishing, hunting |
| ICCF | Institutul Naţional de Cercetare-Dezvoltare Chimico-Farmaceutică | In Romanian | → Chemistry → Pharmacology, toxicology → Chemical technology |
| ICES | International Council for Exploration of the Sea | In French | → Organizations and associations → Earth sciences → Zoology |
| ICES | International Council for the Exploration of the Seas (www.ices.inst.dk) | In English | → Organizations and associations → Marine research, oceanography |
| ICF | Institutul de Chimie Fizica | In Romanian | → Chemistry |
| ICHMT | International Communications in Heat and Mass Transfer | In English | → Serial publications, periodicals → Thermodynamics |
| ICHSEA | International Conference on the History of Science in East Asia | In English | → Congresses → History |
| ICIAM | International Council for Industrial and Applied Mathematics | In English | → Mathematics |
| ICLC | Interlab Cell Line Collection (www.iclc.it) | In English | → Cytology → Biotechnology |
| ICLD | Interlab Cell Line Database | In English | → Cytology → Biotechnology |
| ICM | Inner Cell Mass | In English | → Biological sciences |
| ICMI | International Commission on Mathematical Instruction (www.mathunion.org/ICMI/) | In English | → Organizations and associations → Mathematics → Education |
| ICMPP | Institutul de Chimie Macromoleculara | In Romanian | → Chemistry |
| ICOS | Inducible Costimulator | In English | → Biological sciences |
| ICOS | Integrated Cavity Output Spectroscopy | In English | → Analytical chemistry |
| ICP | Inductively Coupled Plasma | In English | → Plasma physics |
| ICP-MS | Inductively Coupled Plasma Mass Spectrometry | In English | → Plasma physics → Chromatography, mass spectrography |
| ICPDR | International Commission for the Protection of the Danube River | In English | → Organizations and associations → Nature and society → 627 |
| ICPE | Installation Classée pour la Protection de l'Environnement | In French | → Nature |
| ICPO | Institute of Cytology & Preventive Oncology | In English | → Research institutes → Cytology → Oncology |
| ICPS | International Conference on the Physics of Semiconductors | In English | → Congresses → Electricity, magnetism, electromagnetism → 539 → Electrical engineering |
| ICR | Inductance, Capacitance, and Resistance | In English | → Physics → Electrical engineering |
| ICS | International Commission on Stratigraphy | In English | → Organizations and associations → Stratigraphy |
| ICSE | Impact of Computing in Science and Engineering | In English | → Serial publications, periodicals → Computer science → Engineering, technology |
| ICSI | Institutul Naţional de Cercetare-Dezvoltare pentru Tehnologii Criogenice şi Izotopice | In Romanian | → Physics → Applied sciences, technology |
| ICSTI | International Council for Scientific and Technical Information | In English | → Libraries → Engineering, technology |
| ICSU | International Council of Scientific Unions | In English | → Organizations and associations |
| ICSV | International Congress on Sound and Vibration | In English | → Congresses → Acoustics |
| ICTP | Institutul de Calcul Tiberiu Popoviciu | In Romanian | → Computer science → Mathematics |
| ICUAER | International Commitee on Urgent Anthropological and Ethnological Research | In English | → Organizations and associations → Ethnology → Anthropology |
| IDAQP | Infinite Dimensional Analysis, Quantum Probability and Related Topics | In English | → Serial publications, periodicals → Mathematics → Physics |
| IDEMU | Institut de l'Écologie en Milieu Urbain | In French | → Environment, environmental sciences → Ecology |
| IDW | Informationsdienst Wissenschaft | In German | → Libraries |
| IES | Institute for Environment and Sustainability | In English | → Nature → Environment, environmental sciences |
| IES | Electrochemical Impedance Spectroscopy | In English | → Analytical chemistry |
| IET | Instruments and Experimental Techniques | In English | → Serial publications, periodicals → Physics |
| IFB | Interfaces and Free Boundaries | In English | → Serial publications, periodicals → Physics |
| IFEN | Institut Français de l'Environnement | In French | → Research institutes → Nature → Environment, environmental sciences |
| IFIN-HH | Institutul Naţional de Cercetare-Dezvoltare pentru Fizică şi Inginerie Nucleară 'Horia Hulubei' | In Romanian | → Nuclear, atomic, and molecular physics → Nuclear technology |
| IFM | Integrated Flood Management | In English | → Natural disasters → 627 |
| IFM | Institut Français de la Mer | In French | → Research institutes → Environment, environmental sciences → Marine research, oceanography |
| IFP | Institut Français du Pétrole | In French | → Research institutes → Earth sciences → Mining → 665 |
| IFPS | International Federation of Palynological Societies | In English | → Organizations and associations → Paleobotany, palynology |
| IFREMER | Institut Français de Recherche pour l'Exploitation de la Mer | In French | → Marine research, oceanography |
| IFRTP | Institut Français pour la Recherche et la Technologie Polaire | In French | → Research institutes → Earth sciences |
| IfT | Institut für Troposphärenforschung | In German | → Meteorology, climatology |
| IFT | Institutul Naţional de Cercetare-Dezvoltare pentru Fizică Tehnică | In Romanian | → Physics → Mechanical engineering |
| IFZh | Inzhenerno-Fizicheskii Zhurnal = IFZh | Инженерно-физический журнал | In Russian |
In Russian | → Serial publications, periodicals → Mechanical engineering → Thermodynamics |
| IFZh | Инженерно-физический журнал = (look above) |
In Russian | → Serial publications, periodicals → Mechanical engineering → Thermodynamics |
| IGAFS | Issledovaniia Geomagnetizmu Aeronomii i Fizike Solntsa | In Russian | → Serial publications, periodicals → Solar system → Geophysics |
| IGB | Institute for Genomics and Bioinformatics | In English | → Biological sciences → Computer science |
| IGB | Institute for Genomic Biology | In English | → Biological sciences → Genetics |
| IGBMC | Institut de Génétique et de Biologie Moléculaire et Cellulaire | In French | → Genetics → Cytology → Biochemistry, biophysics |
| IGBP | International Geosphere/Biosphere Programme | In English | → Earth sciences → Biological sciences |
| IGDR | Interior Geophysical Data Record | In English | → Earth sciences |
| IGeo | Investigations in Geophysics | In English | → Serial publications, periodicals → Geophysics |
| IGF | Insuline-like Growth Factor | In English | → Biochemistry, biophysics |
| IGG | Istituto di Geoscienze e Georisorse | In Italian | → Earth sciences |
| IgG | Immunoglobuline G | In French | → Biochemistry, biophysics |
| IgIV | Immunoglobuline intraveineuse | In French | → Biochemistry, biophysics |
| IGN | Institut Géographique National | In French | → Geodesy, cartography → Geography |
| IGY | International Geophysical Year | In English | → Earth sciences |
| IHES | Institut des Hautes Études Scientifiques | In French | |
| IHEST | Institut des Hautes Études pour la Science et la Technologie | In French | → Engineering, technology |
| IHP | International Hydrological Programme | In English | → Hydrology |
| IHSR | Iranian Institute for Health Sciences Research | In English | → Biological sciences → Biotechnology → Medicine |
| IHSS | International Humic Substances Society | In English | → Organizations and associations → Earth sciences |
| IHV | Institute of Human Virology (www.ihv.org) | In English | → Research institutes → Virology |
| IIApN | Indian Institute of Astrophysics Newsletter | In English | → Serial publications, periodicals → Astronomy |
| IIAV | International Institute of Acoustics and Vibrations | In English | → Acoustics |
| IIBHG | Institute of Immunobiology and Human Genetics = IIBHG | Institut za Imunobiologija i Humana Genetika | In Macedonian |
In English | → Research institutes → Genetics → Immunology and allergy |
| IIBHG | Institut za Imunobiologija i Humana Genetika = (look above) |
In Macedonian | → Genetics → Medicine |
| IIN | Istituto Italiano di Navigazione = IIN | Italian Institute of Navigation | In English |
In Italian | → Geodesy, cartography → Vehicle engineering |
| IINA | Atti dell'Istituto Italiano di Navigazione | In Italian | → Serial publications, periodicals → Geodesy, cartography → Vehicle engineering |
| IJAEM | International Journal of Analytical and Experimental Modal Analysis | In English | → Serial publications, periodicals → Mathematics |
| IJAEO | International Journal of Applied Earth Observation and Geoinformation | In English | → Serial publications, periodicals → Earth sciences |
| IJApE | International Journal of Applied Electromagnetics and Mechanics | In English | → Serial publications, periodicals → Physics |
| IJAsB | International Journal of Astrobiology | In English | → Serial publications, periodicals → Astronomy → Biological sciences |
| IJBC | International Journal of Bifurcation and Chaos | In English | → Serial publications, periodicals → Mathematics |
| IJBm | International Journal of Biometeorology | In English | → Serial publications, periodicals → Meteorology, climatology |
| IJCEM | International Journal for Computational Methods in Engineering Science and Mechanics | In English | → Serial publications, periodicals → 5196 → Engineering, technology |
| IJCES | International Journal of Computational Engineering Science | In English | → Serial publications, periodicals → 5196 → Engineering, technology |
| IJCFD | International Journal of Computational Fluid Dynamics | In English | → Serial publications, periodicals → 5196 → 532 |
| IJCli | International Journal of Climatology | In English | → Serial publications, periodicals → Meteorology, climatology |
| IJCMS | International Journal of Computer Mathematics | In English | → Serial publications, periodicals → 5196 |
| IJDM | International Journal of Damage Mechanics | In English | → Serial publications, periodicals → Physics |
| IJEaS | International Journal of Earth Sciences | In English | → Serial publications, periodicals → Earth sciences |
| IJEFM | International Journal of Engineering and Fluid Mechanics Spring | In English | → Serial publications, periodicals → 532 → Engineering, technology |
| IJGA | International Journal of Geomagnetism and Aeronomy | In English | → Serial publications, periodicals → Earth sciences |
| IJHFF | International Journal of Heat and Fluid Flow | In English | → Serial publications, periodicals → 532 → Thermodynamics |