Search JSTOR limited to the field of mathematics. You might want to filter out book reviews unless you're interested in using those to identify books to read.
(Searches through citations, reviews, and author information)
A key index of published literature in mathematics. Each article is reviewed and assigned a subject from the Mathematics Subject Classification. Covers 1810 - current.
(Searches through citations, reviews, and author information) An open-access index to published literature in mathematics. Included articles are reviewed and assigned a subject from the Mathematics Subject Classification. Covers 1826 - current.
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"Repository of freely downloadable mathematical works in progress hosted by the American Mathematical Society as a service to researchers, teachers and students. These draft works include course notes, textbooks, and research expositions in progress."