The default search is to select any pages which include any of the search keywords you enter. You can override this behaviour by preceding the keywords with special characters.

If the keyword starts with + then that keyword must appear in the page.

If the keyword starts with - then that keyword must not exist on the page.

If you want to match an exact string include "quotation" marks around the keywords that make up that string. 

To search for beer in a glass you could use +beer -bottle. This would select pages that include the word beer but not those pages that contain the word bottle.

To search for beer glass you could use +beer +glass as this search would only include pages with both keywords.

To search for a name you could use "Woodfordes Wherry" as this would require the exact string to be present.