Perhaps you should try some spelling variations:
yuan china » tuan china, yunnan china, wuhan china
china gene » china gender, china agenda
yan yuan » yan guan, fang yuan, nan yan
wong sam » wong sau, wong lai, kong sar
yang xi » yang yi, yang jui
won sau » wong sau, wong siu
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 yuan china gene ((yang xi) OR (yang di)) ((won sau) OR (wong sam)) ;~.
• Adding a wildcard symbol may retrieve word variants: wang yan yuan china gene ((yang xi) or (yang di)) ((won sau) or (wong sam)) ;*.