Physics research at NIST includes everything from improving the safety of medical radiation procedures to developing future quantum information technologies that generate unbreakable codes.
Elsevier is a global information analytics business specializing in science and health.
Science.gov
Any government site is open acces, not copyrighted material. These are the sites, and the index of sites that is most revelant.
Science.gov searches over 60 databases and over 2,200 scientific websites to provide users with access to more than 200 million pages of authoritative federal science information including research and development results.