You can use Boolean operators (+-"*<>~ etc.) to narrow your search. Here are the some common ones:

+ or -
   a leading plus or minus before any word indicates that the word must be present or absent
   +beethoven -symphonies

*
   a trailing asterisk acts as a wildcard
   +beethoven +symph*

""
   a phrase within double quotes returns results where each word must be present, in the order given in the phrase, including punctuation
   +beethoven "string quartets"

< or >
   a leading lesser or greater than character will bump that word's contribution up or down in relevance
   +beethoven >symphonies

A big example:
    +beethoven +quart* >"harmonia mundi" >SACD
   meaning: must have Beethoven, must have words starting with quart, prefer the phrase harmonia mundi and prefer SACD