IEEE XploreContains full-text of IEEE, IET, IEE, and IBM journals and conferences and IEEE standards.
JSTORProvides full-text digital archive of over 700 scholarly journals.
SPIE Digital LibraryIncludes an extensive resource on optics and photonics, providing more than 230,000 technical papers from SPIE Journals (dates vary) and Conference Proceedings (1990 - present).
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Springer E-BooksContains full-text of books/book chapters, conference papers, and journal articles published by Springer. Purdue University Libraries' subscription to e-books starts in 2005 and covers many disciplines.