Some official subject headings related to your research.
Boolean Operators: Search with AND, OR, NOT
Searching term tricks
* Expand the word you are searching to include plurals. etc.: Japan* gives you Japan, Japanese, Japantown
"quotes" Use for phrases: "San Francisco"
OR Use for either or searching: Hayward or Oakland
And Use to combine terms you want to have: San Francisco and "Civil RIghts"
Not Use when you want to eliminate a word from your search (Warning: if you cut a word and it is in an article with words you want, you won't see that article!)