MPRESS/MathNet.preprints
. Even more comprehensive index to mathematical preprints. Covers most European, xxx.lanl.gov/archive/math,
and specific subject archives.
TechXtra, access to a multitude of different types of technology information from a host of different sources.
E-print Network: Research Communications for Scientists and Engineers. Developed by the U.S. Department of Energy (DOE) Office of Scientific and Technical Information (OSTI). Preprints in the areas of physics, materials, chemistry, mathematics, biology, environmental sciences and other areas related to DOE's research interests are included.
NCSTRL. An international collection of computer science technical reports from CS departments and industrial and government research laboratories.