Restricted - Only look at the single best guess for the scott number in a title.
Smart - Look at any apparent scott number in a title.
Extended - Search the entire title.
Descriptions Too - Search the entire title and description.

There are also several advanced search options which you can use:
* Exclusion: You can place a - (minus sign) before any word to exclude it from your search. For example: 591 -pair.
* OR Searching: By default all searches are AND, however you can use OR between any two keywords. For example : Canada 51 OR 57 will return results for both Canada 51 or Canada 57.
* Number Ranges: You can use .. (two periods) between any two numbers (max range is 100) to display all items matching results between those numbers. For example - 235..245 will return resutls for all items from 235 to 245.