Mathematics

A free, digital version of the National Institute of Standards and Technology Handbook of Mathematical Functions.

Extensive library of content covering "math, science topics such as biology, chemistry, and physics, and even reaches into the humanities with playlists on finance and history."

Extensive crowd-sourced mathematical resource. Currently features "a number of innovative interactive elements that enhance its usability for a variety of different readers. These features include:
*The MathWorld Classroom, which provides a set of pop-up "capsule summaries" for more than 300 mathematical terms.
*Extensive citations to books and journal articles, many of which are active hyperlinks.
*Thousands of downloadable Mathematica notebooks."

"The National Science Digital Library provides high quality online educational resources for teaching and learning, with current emphasis on the sciences, technology, engineering, and mathematics (STEM) disciplines"

Award-winning algebra and pre-algebra tutorial site, created by Elizabeth Stapel.

Over 150 biology journals are covered. Not all of them have the full text accessible, but many do. Try putting your keywords in the search box for "All" and selecting "Only Content I Can Access."

Through a variety of materials, events and services, the American Mathematical Society "promotes mathematics awareness to members, the mathematical and sciences communities, decision-makers on Capitol Hill, the media, and the general public."

Professional society that focuses on mathematics accessible at the undergraduate level. Core mission goals include supporting learning and teaching, research and scholarship, professional development as well as public policy. The MAA encourages “students of all ages, particularly those from underrepresented groups, to pursue activities and careers in the mathematical sciences.”