Search is case-insensitive and based on keywords. To match exact phrases, use "quotes". By default without filters this searches only post body text and subjects. Use an asterisk (*) for wildcard.
You may also apply the following filters to your searches: id, thread, subject, name and filename. To apply a filter, simply add to your query, for example, name:Anonymous or subject:"Some Thread". You can use wildcards like filename:*word*.