Perhaps you should try some spelling variations:
thong cong » trong cong, tong cong, thong thong
tranh va » tranh van, trinh va, thanh va
trang va » tran van, hang va
cong tan » cong tac, cong san, cong thanh
toan tai » doanh tai, toan ban, toan cao
toan tap » toan ban
ho hieu » ho chieu, hoi hieu, nho hieu

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

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