A disadvantage to this is that you might not know when entries stop matching all of the search terms. NOT - NOT can be used in special circumstances, such as give you a way to use a homonym. Notice that you always group the NOT in a parenthesis. If you include a - before a search term or phrase, it means that the term should NOT be in all sites that are returned. The final thing you can do to combine your terms is to weight them.
Different engines have different techniques for weighting.
Thus, if there is a facet of the search that you feel needs to be brought out, enter more synonyms for that term. This doesn't always hold true, but it's a good rule of thumb. Examining the Results When you get your results, don't give up hope. I usually look at the first 50 listings - and if there's nothing at all about my topic, I'll try a different search or a different search engine. The more time you spend on term selection and combination, the less time you should have to spend on results analysis.