MetaLib is a federated search engine that searches multiple U.S. Federal government databases, retrieving reports, articles, and citations
USA.gov to browse by topics
Science.gov searches over 50 databases and over 2100 selected websites from 14 federal agencies
DOE Information Bridge access to over 200,000 full-text documents and bibliographic citations of Department of Energy research report literature, legacy documents are added as they become available in electronic format
Environmental Protection Agency - search by topics, find laws and regulations
Science Inventory - a searchable, Agency-wide catalog of science activities such as research, technical assistance and assessments, along with peer-reviewed products
NASA - space exploration, scientific discovery and aeronautics research
PubMed - biomedical literature from MEDLINE Plus, life science journals, and online books
WorldWideScience.org - "A global science gateway—accelerating scientific discovery and progress through a multilateral partnership to enable federated searching of national and international scientific databases and portals." From the U.S. Department of Energy and the WorldWide Science Alliance.
Air University Library Index to Military Periodicals (AULIMP)
Homeland Security Digital Library
Research and Development Descriptive Summaries (RDDS)
Staff College Automated Military Periodicals Index (SCAMPI)
National Atlas of the United States
U.S. Census Bureau Maps and Cartographic Resources
See also Map Libguide