Here are some ways to do Advanced Searches. The database you are using may or may not be set up with these particular indexes, but the principle is the same.
|Entire Document (tx)||competition|
This is a search for articles about the satellite television industry that mention competition. One way to achieve success in an Advanced Search is to experiment with different indexes. Finding a word in the Keyword or Subject index is best, but the Entire Document index, especially in combination, can be an effective search tool.
|Publication Title (pu)||computer shopper|
This is a search for John Dvorak's columns in Computer Shopper. If you have a title index available, you can also find articles or series of articles by title.
|Keyword (ke)||brian mulroney||NOT|
|Entire Document (tx)||airbus||NOT|
|Entire Document (tx)||libel|
This is a search for articles about former Canadian Prime Minister Brian Mulroney except any that mention either Airbus Industrie or libel. This should effectively eliminate any articles about the accusation of kick-backs and Mulroney's subsequent libel suit. Notice that you must use the not operator a second time, rather than the or operator.