Perhaps you should try some spelling variations:
china health » china's health, child health, capita health
health gain » health goals
yang mind » yang cindy, sang minh, tang min
wang can » wang yan, wang ban, wang yang
wang dan » wang yan, wang ban, wang yidan
yang jin » yang jie, yang jun, ying jin
tan » than

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 can) OR (wang dan)) china health gain ((yang mind) OR (yang jin)) hong tan ;~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((wang can) OR (wang dan)) china health gain ((yang mind) or (yang jin)) hong tan ;~".
• Adding a wildcard symbol may retrieve word variants: ((wang can) OR (wang dan)) china health gain ((yang mind) or (yang jin)) hong tan ;*.