To find relevant literature in a catalogue or database you need search terms. You can find these terms in various ways:
As a start you can start brainstorming on your topic, using the knowledge you already have about the subject. Note down all new terms you come across.
Then use these terms, as well as those you have found in handbooks and encyclopedias, for further searching.
Use synonyms for the search terms you have found. Where possible, use different spellings of the search terms and use translations in case you want to use literature in other languages.
In some databases you can use a thesaurus to look for new search terms. In a thesaurus you will often find other terms (broader as well as more specific) that relate to the term you are looking for.
For more information on this, see the chapter ‘Searching and finding’.
If your search produces too many results, you need to make your search terms more specific. You can also add extra search terms. But make sure you do not exclude an important aspect of your subject!
If your search produces too few results, you need to broaden your search terms.