Science.gov is a gateway to "authoritative U.S. government science information including research and development results" available from over 60 databases and over 2200 selected websites from 15 federal agencies.
OSTI is the DOE office that collects, preserves, and disseminates DOE-sponsored R&D results that are the outcomes of R&D projects or other funded activities at DOE labs and facilities nationwide and grantees at universities and other institutions. The information is typically in the form of technical documents, conference papers, articles, multimedia, and software, collectively referred to as scientific and technical information (STI).
NIST is a non-regulatory agency of the US Department of Commerce. Its mission is "to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life."
NIST supplies industry, academia, and government with over 1,300 SRM used to perform instrument calibrations, to verify the accuracy of specific measurements and to support the development of new measurement methods.
Free access to voluntary consensus standards, government unique standards, private industry standards, and international standards that are referenced in the U.S. Code of Federal Regulations. SIBR also includes standards that are used by U.S. Federal Government Agencies in procurement activities.
"Standards.gov offers background materials and useful links for locating information about the use of standards in government. Our primary focus is on federal agency use of standards and conformity assessment for regulatory purposes."