Most of the search facility is self-explanatory, but some could use a little more detail.
The keywords in the search work as a logical AND, so if you search for "Cats dogs" the results will show results containing both words.
By prefixing a keyword with "-" you can ensure that results will not contain that keyword. So "cats -dogs" will return results that contain "cats" but not "dogs".
Similarly, if you want to find results with cats or dogs you can use the logical OR operator "|" - "cats | dogs"
The search system uses stemming so that words using the same stem are also returned. e.g. "snowing" will also return results containing related words such as snow, snowed, snows. There is no way to override this on a search-by-search basis.
By clicking on the "More..." button in the search box, you are taken to the Advanced Search page.
This page gives you additional search options, to narrow results by content type (Threads, posts, profile posts), specify which forums should be searched and also whether results should be presented in order of most recent first or what the search engine considers most relevant first.
Simple Query String Syntax
The simple_query_string supports the following special characters:
+ signifies AND operation
| signifies OR operation
- negates a single token
" wraps a number of tokens to signify a phrase for searching
* at the end of a term signifies a prefix query
( and ) signify precedence
~N after a word signifies edit distance (fuzziness)
~N after a phrase signifies slop amount
In order to search for any of these special characters, they will need to be escaped with \.