HighWire Press

"HighWire Press is the largest archive of free full-text science on Earth! As of 5/26/08, [HighWire Press assists] in the online publication of 1,884,244 free full-text articles and 4,785,577 total articles. There are 15 sites with free trial periods, and 44 completely free sites. 248 sites have free back issues, and 1050 sites have pay per view!"