Directory of Open Access Repositories - OpenDOAR

Directory of Open Access repositories.
(University of Nottingham (UK) and Lund University Libraries (SV) - http://www.opendoar.org).

The original Physics archive at Los Alamos, now also covers Mathematics, Nonlinear Sciences and Computer Science.
(LANL - US - http://xxx.lanl.gov/).

CoRR covers computer science.
(LANL - US - http://www.arxiv.org/archive/cs/intro.html)

NCSTRL covers computer science.
(Cornell University - US - http://www.ncstrl.org)

Articles posted on Clinical Medicine NetPrints have not yet been accepted for publication by a peer reviewed journal. They are presented on the site mainly for the benefit of fellow researchers (read the warning before entering the site).
(BMJ Publishing Group - US - http://clinmed.netprints.org/ of mirror intl-clinmed.netprints.org)