Here is the list of links that may be of interest for mathematicians

  1. Math Sci Net
  2. ISI Web of Knowledge
  3. Google Scholar
  4. Arxiv
  5. Math Phys Arxiv
  6. Math Phys Archive Texas
  7. Zentralblad Mathematik
  8. Springer Link
  9. Springer e-books
  10. Jstor (older issues of Annals of Mathematics, Transactions AMS, and more)
  11. AMS Journals (this is the last five years; earlier is at Jstor)
  12. Encyclopaedia of Mathematics
  13. Mathematical Genealogy Project
  14. 2000 Mathematics Subject Classification