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: " "
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 ($) is used. The help text for each database will tell you how to truncate words.
financ* will generate
*economics will generate
wom*n will generate
Another way to narrow your search is to use subject terms. Subject terms are always applied when books, articles and reports are registered in library catalogues and databases, and these are organised according to certain principles. 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.
Sometimes finding relevant subject terms can be difficult, and some databases do not have a list of subjects. The option in these cases is free text searching, where you search for words included in the information about the publications – such as title and abstract – in the database. In some databases, a free text search will also generate results from the full text of articles and other publications.
Searching with subject terms will often generate a more precise list of results than free text searching.