Web Archives:
Cornell University Library Archives: Arxiv.org
Stanford Linear Accelerator Center(SLAC):Spires
The NASA Astrophysics Data System
Physical Review Online Archive
Science Direct
Journals:
APS Journals: Physical Review A-E, Physical Review Letters, Reviews of Modern Physics.
Elsevier Journals: Annals of Physics, Astroparticle Physics, Nuclear Physics A-B & Supplements, Physica A-E, Physics Letters A-B, Physics Reports, Reports on Mathematical Physics, etc ...
AIP Journals:   Journal of Mathematical Physics
Springer Journals:  Communications in Mathematical Physics, Letters in Mathematical Physics , Theoretical and Mathematical Physics