Perhaps you should try some spelling variations:
nthanh hang » tranh hang, thanh hung, thanh hoang
thanh hang » thanh hoang, thanh thang, tranh hang
thong cong » trong cong, tong cong, thong thong
va thong » va thuong, va phuong, he thong
cong dan » cong san, cong tan, huong dan
ho hieu » ho chieu, hoi hieu, nho hieu
dan van » dang van, doan van, dao van

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 - ((nthanh hang) or (thanh hang)) va thong cong dan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho hieu qua - ((nthanh hang) OR (thanh hang)) va thong cong dan van ban*.