Placing quotation marks around search terms, in effect, does an exact search. The quotation marks tells SearchWorks to do a phrase search. The query "computer science" (with quotation marks) would return records containing "computer science" but would not return records containing "computer and information science." It would also return records containing the phrase "theoretical computer science" and "relational methods in computer science." Records with just "computer science" in the title will appear at the top of the results list.
Single term searches with quotation marks will not have the same outcome as with multiple term searches with quotation marks. This is because phrase searching (searches with quotation marks) is affected by the query slop setting, which determines the distance that can separate the query terms. Query slop cannot apply to single term searches. See slop in the Technical Glossary for more details.