Searching by subject allows you to find sources that may not have turned up with your keyword search. A keyword search looks for word-for-word matches of the terms you typed in. Subjects are a controlled vocabulary applied to each item in the library catalog that describe what the source is about.
One of the best ways to search by subject is to start with a keyword search.
African Americans Social conditions.
African Americans Study and teaching (Higher).
African Americans Relations with Africa.
African American women Political activity.
African American Social reformers.