arXiv is a preprint service and an open-access archive for scholarly articles in the fields of physics, mathematics, etc. Materials are not peer-reviewed by arXiv.
PROLA - Physical Review Online ArchiveThis link opens in a new windowThe Physical Review Online Archive (PROLA) is the American Physical Society's online archive for Physical Review Letters, Reviews of Modern Physics, and Physical Review A–E. It contains all APS journal articles published from 1893–2010. Each January, another year is added to the archive.
SpringerLINK Contemporary - Community PlusThis link opens in a new windowThis is a multidisciplinary collection of journal and eBooks with more than 2,400 scholarly titles in a wide range of subjects: health sciences, science, and social sciences. Content is available from 1997.