Symbolab is a site I learned about from David Kapuler on his blog. It is a "Science and Math Search Engine" and makes it easier to find science content online. It specifically searches for science content using semantic search tools.
You can search from the site, or use a free download for Chrome and Firefox.
The other unique feature that truly sets it apart is that it lets you use math and science symbols and equations to search. This is especially helpful when searching for topics that are related to a formula or symbol, vs. just a word.
Share this with your science and math educators and students.
STEM (Science, Technology, Engineering, and Math) Resources for Educators and Students