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Google is good at ignoring words that don't relate to your topic (like the, a, why, etc.). Databases usually take your search literally so only search for the main ideas for your topic.
Example Google search: "why does the earth spin"
Example database search: "earth rotation"
Don't assume a database ranks relevant results like Google. In databases, refine your searches to have a manageable number of results.
Choose the kind of words that would be used in your desired result.
For academic research, think of terminology that's most likely to be used by scholars in that discipline.
To discover search terms, try a glossary. For example, a Google search for "anthropology glossary" gives several good results. You could also look for terms in a textbook, in the subject index in a disciplinary database, or by talking to your professor.
When using a new database, look for the range of search filters (usually on the homepage or the side of search results). For example, in addition to the typical filters, Historical Abstracts lets you filter by era of the topic.
Evaluate your results. Try multiple searches, and refine your terms and your tools as you go.