Perhaps you should try some spelling variations:
iran health » urban health, migrant health, german health
hyoung tan » hyoung gun, hong tan
young man » young men, young woman, young male
yan iran » year iran, law iran, yan clan
yang jin » yang jie, yang jun, shang jin
ying jin » jing ji, yang jie
wang » wing, wan, lang

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

• If you are trying to use Boolean operators, they must be ALL CAPS: wang yan iran health goals ((yang jin) OR (ying jin)) ((hyoung tan) OR (young man)) ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wang yan iran health goals ((yang jin) or (ying jin)) ((hyoung tan) OR (young man)) ;~".
• Adding a wildcard symbol may retrieve word variants: wang yan iran health goals ((yang jin) or (ying jin)) ((hyoung tan) OR (young man)) ;*.