By knowing the most common search methods, you'll be able  more quickly and simply to find relevant information in databases and on the Internet. By combining search terms in various ways and using different finding tools you'll be able to narrow down or expand your searches. 

Boolean searches

Most online library catalogues (e.g. DISA, LIBRIS), databases and search engines (e.g. Google) use the same system to combine words in different ways. The method is called boolean searching. 

The most common for databases is to use three commands/operators: AND, OR, NOT.

AND – narrows your search and leads to fewer hits. Use AND when two or more words or terms must be in the same sources/reference.
Example: European Union AND Enlargement

OR – expands your search and gives a greater number of hits. Use OR for example when your search term has synonyms.
Example: EU OR European Union 

NOT – narrows your search and leads to fewer hits. Use NOT when you want to exclude certain words or terms.
Example: Subsidies NOT Livestock       

Truncation

In most databases and search engines you can expand your search by substituting letters in a word with a symbol. The most common is an asterisk (*), but sometimes a question mark (?) or a dollar sign ($) are used. The help texts for each database will tell you how to truncate words.

Example: 
A search for  financ* will generate a list including financial, finances, financial indicators etc.  
A search for *economics will generate a list including macroeconomics, microeconomics, etc. 
A search for wom*n will generate a list including both woman och women.

Phrase searches

If you want to search for a string of words or a concept consisting of more than one word you can use phrase searching. The most common way is to enclose the words in quotation marks (" "). The help texts for each database will tell you how to do phrase searches.

Example: "foreign languages", "global warming".

Descriptors

Another way to narrow your search is to use the "descriptor" function. Descriptors or subject words are always used when books, articles and reports are registered in library catalogues and databases, and these are organised according to certain principles.

Descriptors vary in different databases, countries and subject areas. You can find these words under headings such as "subject", "index" or "thesaurus". Check which descriptors are used in the particular database you are accessing and use them in your searches. This is an easy way to find relevant information.