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Basics of Information Retrieval: Information retrieval

Combining the search words

From database to database search words are combined with Boolean operators (AND, OR, NOT). To get the best result it is still worthwhile to check the guidelines for each database:

Boolean operators working


phones AND marketing

AND-operator specifies the search. It searches for material containing all the search terms.


phone OR cell OR cellular

OR-operator expands the search. It is enough that some search words are found in the result. OR-operator is practical when using synonyms.


marketing NOT telemarketing

NOT-operator limits the search. It excludes some search words from results. Be careful with this operator - applying it can easily leave useful material outside the result list.


Example topic: marketing of mobile phones. Search could be 

(phone OR cell) AND marketing

You can add synonyms and related terms to get better results:

(phone OR cell OR cellular) AND (marketing OR selling OR trading)

Boolean operators (PfauLibrary)

Search term truncation

Sometimes it is useful to truncate a search word for taking into account different forms of the term. Symbols used for truncation vary, so check the symbols from the database you are using. The most usual wildcard characters are: *, ?, $ and #.

process* > processor, processing, processed, process, processes and processors
*cattle* > beef cattle, cattle breeds, cattle raising

Phrase search

If you want to search a phrase (two or more words in a specific order), use quotation marks around the words. Without quotation marks, many databases are looking for search words individually and the results will contain a lot of irrelevant material. For details, check the guidelines for each database.

"Social media"
"human resources management"

Search limits

It is often useful to limit your search to get more precise results. How to limit your searches will vary from database to database. The most common "limit" commands are "by date," "by language," or "by publication type." In most of the databases, you can also limit your searches to author, title or keywords.