A good way to begin your search is to use a dictionary or a specialized lexicon of terms (thesaurus) to identify suitable search terms or synonyms and broaden your search. Many databases include this feature, also called "Subject Terms", "Subject Headings", or "Descriptors".
Finto Vocabularies and ontologies (Finnish, English, Swedish)
MOT Dictionaries
LCHS Library of Congress subject headings
MeSH Medical subject headings
ERIC Education-related terms
Finmesh English-Finnish medical and health terms
Grove Music Online
AFO Agriculture and Forestry Ontology
EnDic environmental dictionary
bab.la - Online dictionary for 28 languages
Kielitoimiston sanakirja - Dictionary of standard Finnish
RedFox Dictionary Basic - Free Dictionary includes 41 languages
TEPA Term Bank - Special language terms and their definitions, displayed as multilingual terminological entries
Your Dictionary - English words and grammar
Valter Government Termbank - Multilingual termbank, contains e.g. budget, EMU, education, taxation and court terms