Use AND to connect words that must appear in a document. This *narrows* your search.
"toxic waste" OR "hazardous waste"
Use OR if only one word must appear in a document. This *broadens* your search.
sustainab*
Use an asterisk to truncate a word and allow for different endings, for example, sustainable, sustainability, sustainably. (But be careful because there could be words with the same beginning that are unrelated.)
"sustainable development"
Use quotation marks to enclose a phrase or words that must appear together in a document.
plastic NOT surgery
Use NOT to exclude words or terms from a search. If you're looking for articles on plastic in the context of pollution, articles about plastic surgery are not going to be relevant.
Library Guides -- and Subject Guides in particular -- can help you choose databases that are relevant to a specific disciplinary approach. There is a Subject Guide that corresponds with each Whitman major. General Guides offer information about certain kinds of sources, such as government documents or primary sources.
The advanced search interface lets you be more specific in your Google search: search within specific domains, for results with specific licenses, in specific languages, etc.