Sometimes you may get good search results using just one term. But sometimes you may get too many results using only one term and it can be very tedious to pick the relevant hits out of that long list. Mostly it is better to combine two or more search terms into search statements. The logic behind the combination of search terms is called Boolean logic and the words are combined by Boolean operators.
The Boolean operators AND, OR, NOT are used to combine two or more search terms.
AND is used to combine two different concepts. You will find all the records that contain both terms, e.g. design AND games, climate AND flowers. The more AND operators you use, the fewer results you get.
OR is used to combine alternatives, synonyms, or broader and narrower terms. You will find all the records that contain one or the other term or both terms, e.g. design OR programming, TV OR television, teenagers OR youth. The more OR operators you use, the more results you get.
NOT is used to leave out a term. You will find all the records containing first term except for those that also contain the other term, e.g. Europe NOT Scandinavia, media NOT television. The more NOT operators you use, the fewer results you get.
Tutorial: AND, OR, NOT (The University of Auckland Library)
Truncation and phrases
Truncation can be used in order to find all the inflected forms of keywords as well. The truncation mark can be different in different databases, e.g. * (an asterisk) or ? (a question mark). When using truncation, the results of the search will contain all of the documents that contain any word that begins with the string that precedes the truncation mark, for example the keyword school* can be used to retrieve documents that contain any of the following terms: school, schools, schooling.
Put phrases in quotation marks, e.g. "international cooperation", "web-based learning"
Search Profile Example
The topic is "Computer-aided game design". You have chosen your search terms: computer, games, design, design patterns, computer-aided design, players, video games, programming, computer graphics.
Try first with two terms: game? AND design
If you get too many records, add one term more: game? AND design AND computer?
Try to search with related terms also: game? AND (design OR programming) AND (computer? OR video)
Try to search also with added concepts: