Astronomy & Physics
The SAO/NASA Astrophysics Data System (ADS) is a Digital Library portal for researchers in Astronomy and Physics, operated by the Smithsonian Astrophysical Observatory (SAO) under a NASA grant. The ADS maintains three bibliographic databases containing more than 8.7 million records: Astronomy and Astrophysics, Physics, and arXiv e-prints.
The Durham HepData Project has for more than 25 years compiled the Reactions Database containing what can be loosly described as cross sections from HEP scattering experiments. The data comprise total and differential cross sections, structure functions, fragmentation functions, distribuitions of jet measures, polarisations, etc... from a wide range of interactions. They are all made publically available in the Reaction Data Database.
The National Space Science Data Center serves as the permanent archive for NASA space science mission data. "Space science" means astronomy and astrophysics, solar and space plasma physics, and planetary and lunar science.
The UKSSDC supports data archives for the whole UK solar system community encompassing solar, inter-planetary, magnetospheric, ionospheric and geomagnetic science.
The Virtual Atomic and Molecular Data Centre (VAMDC) is a major new European initiative that has built a unified, secure, documented, flexible and interoperable e-science environment-based interface to 24 existing A+M databases.
The Weizmann Institute of Science Plasma Laboratory maintains a directory of databases for atomic and plasma physics.