MIT OpenCourseWare (OCW) is a web-based publication of virtually all MIT course content. OCW is open and available to the world and is a permanent MIT activity
The arXiv, hosted at arXiv.org by the Cornell University Library, stores over a half million e-prints in Physics, Mathematics, Nonlinear Sciences, Computer Science, Quantitative Biology, Quantitative Finance, and Statistics.
WolframAlpha introduces a fundamentally new way to get knowledge and answers—not by searching the web, but by doing dynamic computations based on a vast collection of built-in data, algorithms, and methods.
