The Library has a lot of encyclopedias on more specific topics, and these can be especially useful when you're starting your research.
One way to search for them in Library Catalog Search is to use the topic as a keyword search. A search for "encyclopedia of medieval women" will bring up Women and gender in medieval Europe : an encyclopedia / Margaret Schaus, editor.
When that doesn't work, try an advanced Library Catalog Search using "encyclopedias OR dictionaries" as a SUBJECT term and your topic as an keyword term.
For example:
All Fields: medieval (women OR gender)
Subject: encyclopedias OR dictionaries