Perhaps you should try some spelling variations:
duong van » cong van, duong anh
van china » can china, dan china, han china
china aus » china als, china auf, china aids
yang july » yang judy, yang jui, yang jun
lang hua » wang hua, wang hui, gang hu
dong hua » wang hua, tong hui, dong hoi
yang yi » yang xi, yang jui

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

• Performing a fuzzy search may retrieve terms with similar spellings: duong van china china aus ((((yang yi) or (yang di))) or (yang july)) ((lang hua) or (dong hua)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: duong van china china aus ((((yang yi) OR (yang di))) OR (yang july)) ((lang hua) OR (dong hua)) ;*.