If you are looking for a few highly relevant articles on a subject, consider using the PubMed Best Match feature, available in the Sort menu.
Best Match uses machine learning to rank the results by relevance and present the best matches at the top. View the Best match search information in the right column to see mapped MeSH terms. Click See more to view additional synonyms.
Note that Best Match is a different search. It is not a comprehensive search of PubMed. For comprehensive searches, use a different "Sort" option.