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When you search in academic databases, keywords give you the best search results. Next time you search, instead of typing in a long phrase such as "all the research that shows evidence to prove there's no life on the moon," try keywords.
A better search about lunar life would use keywords and look like this:
"life on the moon" and research
Tip: Use quotes " " to search for a phrase. Sometimes the database will recognize a phrase even without quotes but by using quotes, you can be sure. This trick works in Google, too!