Science & Technology
- DTIC Online (Defense Technical Information Center)
- Geological Survey, U.S. (USGS)
- GrayLIT Network (Retired website). See: Science.gov
- Journal Sources (Office of Scientific and Technical Information)
- NASA STAR. See: NASA Technical Reports Server (NTRS)
- National Aeronautics and Space Administration (NASA)
- National Institute of Standards and Technology (NIST)
- National Oceanic and Atmospheric Administration (NOAA)
- Nuclear Regulatory Commission (NRC)
- National Science Foundation
- National Technical Information Service (NTIS)
- National Technical Reports Library (NTRL)- NTIS
- Office of Scientific and Technical Information (OSTI)
- Science.gov
- ScienceResearch.com (non-government, free search engine)
- SciTech Connect (Energy, Engineering, and Science Research Database). Now: OSTI.gov
- Smithsonian – Explore Science
- Smithsonian Insider – Science and Nature
- TRAIL – Technical Report Archive & Image Library