SuperSearch is a great place to start for journal articles, books and almost everything else the library has, in one easy to use interface.
For searching with more focus and precision, try one of the databases recommended on this guide.
Find scholarly articles in subject-specific databases.
Grey literature (read a helpful definition here) is not published in traditional commercial venues nor included in major databases. It can take the form of research reports, theses and dissertations, newsletters, bulletins, pamphlets, blog entries, and more.
Grey Literature Report - From the New York Academy of Medicine. This website and database stopped being updated as of January 2017. The resources are still accessible and searchable, however. This site also has links to other medica grey literature sources.
Research Guide to Grey Literature - History of Medicine - NYU Libraries