Perhaps you should try some spelling variations:
phan china » han china, than china, wuhan china
china aids » china air, china adb, china als
duong van » cong van, duong anh
yang july » yang judy, yang jui, yang jun
van phan » dan phan, van thanh, van ham
yang yi » yang xi, yang jui
wang » 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: duong van phan china aids ((((yang yi) OR (yang di))) OR (yang july)) (wang OR wing) hua ;~.
• Adding a wildcard symbol may retrieve word variants: duong van phan china aids ((((yang yi) or (yang di))) or (yang july)) (wang or wing) hua ;*.