Use AND to connect words that must appear in a document. This *narrows* your search.
Sufism OR "Islamic Mysticism"
Use OR if only one word must appear in a document. This *broadens* your search.
feminis*
Use an asterisk to truncate a word and allow for different endings, for example, feminists, feminism, feminist, etc.
"Sufi whirling"
Use quotation marks to enclose a phrase or words that must appear together in a document.
Babel NOT Isaac
Use NOT to exclude words or terms from a search. (If you're looking for articles on the Tower of Babel, you don't want articles on literature by Isaac Babel.)
Parentheses
Think about it like order of operations when you are using multiple operators:
Sufism AND ("gender roles" OR feminine)