Open access to 546,172 e-prints in Physics, Mathematics, Computer Science, Quantitative Biology, Quantitative Finance and Statistics
ADS contains abstracts and citations for materials in astronomy and astrophysics, instrumentation, physics and geophysics, Los Alamos preprints, and many archives.
Searchable database of citations for articles in 'Mathematical Reviews' from the American Mathematical Society. Covers mathematics, statistics, engineering, and the physical sciences. Full-text links to many original articles from the American Mathematical Society. Tutorials are available at http://www.mathscinet.info/index.html
Includes approx. 90,000 full-text papers from SPIE Journals and Proceedings published since 1998. It also includes citations and abstracts for most SPIE papers published since 1995.
Multidisciplinary index to scholarly and authoritative articles. Provides access to all three parts of the Citation Index: Arts and Humanities, Social Science and Science. Search by subject, author, journal title. Cited Reference Search finds articles that cite an author or article that you specify.