Perhaps you should try some spelling variations:
zhang ming » zhang xin
van thanh » tran thanh, phan thanh, lam thanh
thanh van » thanh dam, thanh vu
van zhang » yan zhang, bin zhang, hao zhang
hong gang » gong gang, hong wang, hong kong
wang van » wang yan, wang ban, wang dan
gong min » jong min, song min, gong meng

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 van thanh van zhang ((tan kim) OR (zhang ming)) ((gong min) OR (hong gang)) ;~.
• Adding a wildcard symbol may retrieve word variants: wang van thanh van zhang ((tan kim) or (zhang ming)) ((gong min) or (hong gang)) ;*.