The Advanced Search offers numerous options for making your searches more precise and getting more useful results. You can reach this page by clicking (no surprise) the "Advanced Search" link.  You can do a lot more with the Advanced Search than just typing in search terms. With Advanced Search, you can search only for pages: 
 
- that contain ALL the search terms you type in
- that contain the exact phrase you type in
- that contain at least one of the words you type in
- that do NOT contain any of the words you type in
- created in a certain file format
- that have been updated within a certain period of time
- that contain numbers within a certain range