Use AND to connect words that must appear in a document. This *narrows* your search.
bilingual OR multilingual
Use OR if only one word must appear in a document. This *broadens* your search.
translat*
Use an asterisk to truncate a word and allow for different endings, for example, translation, translator, translating, etc.
"simultaneous translation"
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 the author Isaac Babel.)