Perhaps you should try some spelling variations:
thanh trong » thanh trung, tranh trong, hanh trong
hieu lang » chieu sang, hieu quang, nhieu tang
trong tac » trong cac, tuong tac, trong tan
doc hieu » toc thieu, hoc thieu, hoc hien
tac dung » sach dung, xay dung, tin dung
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
than cap » thanh lap, thanh cac, than cua
khan cap » khan ap, khoan cam, phan cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu lang - thanh trong tac dung ((cong dan) or (cong san)) ((than cap) or (khan cap))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - thanh trong tac dung ((cong dan) OR (cong san)) ((than cap) OR (khan cap)).
• Adding a wildcard symbol may retrieve word variants: doc hieu lang - thanh trong tac dung ((cong dan) or (cong san)) ((than cap) or (khan cap))*.