Perhaps you should try some spelling variations:
wang oanh » wang yan, wang yang, dang anh
chen yang » chen rong
john song » john wong, john bonn, john ngosong
tran hua » tan hua, tuan hua
tran duc » tran dat, tran dai
ren yang » ren yan, pei yang, ren weng
dan yang » daun yang, tan yang, wang yang
song sam » wong sam, kong sar, song pae

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

• Performing a fuzzy search may retrieve terms with similar spellings: wang oanh ((tran hua) or (tran duc)) ((((ren yang) OR (chen yang))) or (dan yang)) john song sam ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: wang oanh ((tran hua) OR (tran duc)) ((((ren yang) OR (chen yang))) OR (dan yang)) john song sam ;.
• The words AND, OR and NOT may confuse the search; try adding quotes: "wang oanh ((tran hua) or (tran duc)) ((((ren yang) OR (chen yang))) or (dan yang)) john song sam ;".
• Adding a wildcard symbol may retrieve word variants: wang oanh ((tran hua) or (tran duc)) ((((ren yang) OR (chen yang))) or (dan yang)) john song sam ;*.