ScienceResearch.com: Free Access to Scientific and Technical Literature

Science.com is a "free, publicly available web portal allowing
access to numerous scientific journals and public science
databases. " Topics covered include biology, chemistry,
computers, environmental sciences, engineering, health
and medicine, materials science, mathematics, physics, and
social sciences.

Sources include open access journals, the Library of Congress
online catalog (for bibliographic citations only), Science.gov
(government information from 30 databases and more than
1,700 science websites), science conference papers and
proceedings, and scientific news from popular science
web sites.

Hat tip to Librarians Internet Index.