Perhaps you should try some spelling variations:
iran health » urban health, migrant health, german health
han health » human health, ghana health, when health
hyoung tan » young man, hong tan
hyoung gun » young eun
gain yang » dan yang, daun yang, tan yang
yang jin » yang jie, yang jun, ying jin
wang » wing, wan, lang

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

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