When you have defined your search topic, you then list key concepts and words describing your topic. You can do, for example, a mind map which helps you better understand the relationships between concepts/words and thus your topic as a whole. Good search terms are crucial for successful information searching.
You can search for information with any term or word describing your topic that you can think of and thus utilize the latest terminology within the field. Use also reference books, theoretical literature, specialized dictionaries and articles to find new search terms. You can search in several databases with the search terms you come up with yourself but remember that the number of search results might be very high and many of them irrelevant.
In addition to searching for information with any term describing your topic, use also subject terms. Materials in databases are described with subject terms that are taken from controlled vocabularies. In these controlled vocabularies a certain term with a certain wording is used to describe a singular phenomenon. When you search with the same subject terms that have been used to describe the material, you get less search results but they are more relevant. The latest terminology is not, however, necessarily available in controlled vocabularies.
Controlled vocabularies are often database-specific but not all databases have one. If you are not getting good search results, check the vocabulary whether the search term you used is actually a subject term in that particular database. Controlled vocabularies are usually called Thesaurus, Subject Headings or Subject Terms.
Controlled vocabularies also include relationships between terms by listing broader, narrower and related concepts which can help you understand your search topic better and come up with new search terms.
Most Finnish libraries use a controlled vocabulary called YSO to describe their material:
You can translate search terms to different languages with, for example, MOT or other dictionaries. Take also into consideration abbreviations, and utilize a thesaurus to look for synonyms.