You can make use of wildcards, such as monkey* to return anything starting with "monkey". You can also make use of boolean logic such as: monkey AND NOT butler, for example, to return items that contain "monkey" but not "butler" (note that the boolean terms must appear in capitals). Place items in quotes to look for phrases, e.g. "monkey butler" to only find items that contain this exact phrase.
Search terms are not case sensitive. Case sensitivity is only important when using terms such as AND, OR, NOT to indicate boolean logic in the search.
You can also make use of the fields that are indexed to help you search, so for example, if you want to look for a post you made about Nu Shooz on a given board, you can enter the following in the search field and select the board from the drop-down.
text:"nu shooz" AND loginId:firstname.lastname@example.org
The fields you can use are: text (the body of the post), title (the title of a thread), displayName (the name you see attached to the thread or post) and loginId (your login/email address).