Perhaps you should try some spelling variations:
thanh dung » thanh duong, thanh tung, thanh hung
thong cong » trong cong, thong thong, phong chong
hieu lang » chieu sang, hieu quang, nhieu tang
tong cong » trong cong, cong cong, dung cong
thanh cac » hanh cac, thanh bac, thanh ca
dung cua » dung luan, dung cho
than cap » khan cap, thanh lap, than cua
ho hieu » ho chieu, hoi hieu, nho hieu

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: ho hieu lang - thanh dung cua ((thong cong) OR (tong cong)) van ((than cap) OR (thanh cac))~.
• Adding a wildcard symbol may retrieve word variants: ho hieu lang - thanh dung cua ((thong cong) or (tong cong)) van ((than cap) or (thanh cac))*.