A search engine that allows you to enter your query, then select a credible source to search for that term in. These include JStor, the Library of Congress, Ebscohost, Eric, the Internet Archive, and many more.
TinEye is a "reverse" search engine: you upload an image file, and it finds all the places on the Internet where that same photo (or a lightly altered version) has been found. This can be useful if you are looking for the original version of a picture (rather than someone's repost).