Examples: <br/> <br/> +happy +(dog or cat) <br/> "happy dog"<br/> (foo OR bar) AND (baz OR boo)<br/> ((a OR b) AND NOT c) OR d)<br/> +(apple "steve jobs") -(banana orange pear)<br/> +title:(dog OR cat) -author:"bob dobbs"<br/> +(luc*) -(ball)<br/>