History

Boolean:
Use OR to include search terms, otherwise use AND and NOT to exlude. Note that these Boolean operators must be capitalized.

college enrollment AND diversity

Quotation Marks:
Use quotation marks to search for exact phrases. This is especially helpful for titles.

"capital in the twenty-first century"

Parentheses:
Use parentheses to group together related terms.

("Affordable Care Act" OR Obamacare) AND "birth control"