Perhaps you should try some spelling variations:
guan china » tuan china, wuhan china, human china
china wen » chia wen, china won, ching wen
yan guan » gan guan, yan yuan, yang guang
yang jin » yang jie, yang jun, shang jin
ying jin » jing ji, yang jie
wan yan » wang yan, nan yan, wai yan
yan jiu » yang jie, pang jiu

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: wan yan guan china wen ((yan jiu) OR (((yang jin) OR (ying jin)))) cong shu ;~.
• Adding a wildcard symbol may retrieve word variants: wan yan guan china wen ((yan jiu) or (((yang jin) or (ying jin)))) cong shu ;*.