1. keywords; narrow your focus by adding another search term; variant word endings
female* infanticide china
* = truncation symbol/wildcard; child* = child, childs, children, childhood, childish...
on the left, limit to scholarly/peer reviewed articles; or limit to books, limit by language...
2. phrase searching.
"mental illness" stigma* "asian american*"
looking through the results, you might look broaden your search:
"mental illness" stigma* cultur*
"southeast asian*" refugee* "post trauma*"
you might broaden your results:
"southeast asian*" refugee* trauma*"
3. look for official subject headings:
genome editing moral and ethical aspects (subject)
4. advanced search
obesity or diabetes