You can start with a keyword search in the catalog, but be sure to look at the subject headings for books and videos that are relevant to your topic. Then search those headings. For instance, a search on Rosie the Riveter, commonly used to refer to women who worked in factories during World War II, will retrieve works that have the subject headings:
World War, 1939-1945 -- Women -- United States
Women -- Employment -- United States -- History -- 20th century
When you click on a subject heading in a record, you are taken to a hierarchical list of headings, so you will also find
World War, 1939-1945 -- Women -- United States -- Correspondence
Browse a bit more and you will also find
World War, 1939-1945 -- War work
If you want to search the subject heading database, go to the
These same subject headings will be used in WorldCat.