Perhaps you should try some spelling variations:
trinh quan » tinh quang, trinh han
thong cong » trong cong, tong cong, thong thong
hieu lang » chieu sang, hieu quang, nhieu tang
hai hieu » hai chieu, hoi hieu, phan hieu
cong tan » cong tac, cong san, cong thanh
tan toan » tan tran, tap toan, van toan
toan ban » van ban

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: hai hieu lang - hanh ((trinh quan) OR (trinh luat)) thong cong tan toan ban~.
• Adding a wildcard symbol may retrieve word variants: hai hieu lang - hanh ((trinh quan) or (trinh luat)) thong cong tan toan ban*.