There are certain search techniques you can apply in different databases and library catalogues to get more relevant results. These techniques can vary somewhat from database to database, so make sure you read the help text in a database before you begin searching.
Most online databases and search engines use the same system to combine words in different ways. The method is called boolean searching. The most common 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 source/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: Cancer NOT Lung
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: " "
Another way to narrow your search is to use subject terms. Subject terms are decided on by the database provider and are standardize the language that describes individual articles. Subject terms vary in different databases, countries and subject areas. You can find these words under headings such as "subject", "index" or "thesaurus". Check which subject terms are used in the particular database you are accessing and use them in your searches. This is an easy way to find relevant information.