Perhaps you should try some spelling variations:
yunnan china » urban china, tuan china, wuhan china
duong van » cong van, duong anh
china als » china aus, china aids, china a
yang jun » yang jui, pang jun, yang jin
wang wei » zhang wei, wang zhi
yang yi » yang xi, yang jui
dong di » dong sin

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: duong van yunnan china als ((((yang yi) OR (yang di))) OR (yang jun)) ((wang wei) OR (dong di)) ;~.
• Adding a wildcard symbol may retrieve word variants: duong van yunnan china als ((((yang yi) or (yang di))) or (yang jun)) ((wang wei) or (dong di)) ;*.