+ All search result must contain this word. - No search result must contain this word. * The wildcard, indicating zero or more characters. It can only appear at the end of a word. " Anything enclosed in the double quotes is taken as a whole (so you can match phrases, for example).
Examples +great -bad Search result must contain "great", but cannot contain "bad".
"This is great" The search result must contain this exact phrase.
great* Search result will match great and greatest.