Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu quan » hieu qua, lieu quan, thien quan
hoi hieu » hoi phieu, hoi tieu, moi hieu
tranh va » tranh van, trinh va, thanh va
trang va » tran van, hang va
cong san » cong tac
toan ban » van ban

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoi hieu quan - canh ((tranh va) or (trang va)) nhung cong san ((toan ban) or (toan tap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoi hieu quan - canh ((tranh va) OR (trang va)) nhung cong san ((toan ban) OR (toan tap)).
• Adding a wildcard symbol may retrieve word variants: hoi hieu quan - canh ((tranh va) or (trang va)) nhung cong san ((toan ban) or (toan tap))*.