Many conference papers and articles from the Association for the Advancement of Artificial Intelligence are freely available through their Digital Library.

Full-text primary literature of computing and computer science published by Association for Computing Machinery (ACM); from 1954 to present

Khan Academy is a set of 1000+ videos covering everything from basic arithmetic and algebra to differential equations, physics, statistics, chemistry, biology and finance. Includes SAT and GMAT prep.

Science.gov searches over 60 databases and over 2,200 scientific websites to provide users with access to more than 200 million pages of authoritative federal science information including research and development results.

Site with 1000+ reviewers that cover all aspects of computers including reviews on books, articles, hardware and services.

GitHub is a development platform inspired by the way you work. From open source to business, you can host and review code, manage projects, and build software alongside 31 million developers.

SourceForge is an Open Source community resource dedicated to helping open source projects be as successful as possible.