Perhaps you should try some spelling variations:
iran health » urban health, migrant health, german health
han health » human health, ghana health, when health
young male » young males, young age
yang mind » yang cindy, sang minh, tang min
lang yan » wang yan, wang yang, zhang yan
yang jin » yang jie, yang jun, ying jin

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: lang yan ((han health) or (iran health)) gain ((yang mind) or (yang jin)) young male ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: lang yan ((han health) OR (iran health)) gain ((yang mind) OR (yang jin)) young male ;.
• Adding a wildcard symbol may retrieve word variants: lang yan ((han health) or (iran health)) gain ((yang mind) or (yang jin)) young male ;*.