Open Archives Initiative OAI 2.0
Science, Math, Publications, Search Engines - My OAI. A full-featured search engine for most of the major E-print/preprint servers.
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Front for the LANL ArXiv
Science, Math, Publications, Search Engines - Front for the LANL ArXiv. Easiest search access to papers posted on the preeminent Los Alamos National Lab (LANL) Physics and Mathematics preprint server (arXiv).
http://front.math.ucdavis.edu/