In the search box, type a few words, a Proper Name, or a full question. Pluses and Minuses can be combined in one string. This narrows search results by searching for one word, and then within that set of results, for another. WebCrawler suggests you supply synonyms, implying that it does not do this. AND finds pages that include both terms, OR finds pages that include either term or both, NOT finds pages that include the first term but not the second - e.g. science NOT fiction, NEAR finds pages in which both terms appear within x words of each other in either direction.
Short format lists titles of Web resources.
Detailed format provides titles plus summaries, URLs, numerical relevancy scores, and the option of viewing similar pages for each result returned. Yahoo finds all keyword matches, then sorts the results according to relevancy within each specific area. The Options page lets you specify 20-100 matches per page.