Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu lang » chieu sang, hieu quang, nhieu tang
trung cao » truong cao, trung cap, trung co
doc hieu » toc thieu, hoc thieu, hoc hien
cao dung » cao dang, cao dong, cao ung
cong san » cong tac
cong tan » cong tac, cong thanh, cong ty
than cap » khan cap, thanh lap, thanh 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 trung cao dung ((cong san) or (cong tan)) than cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - thanh trung cao dung ((cong san) OR (cong tan)) than cap.
• Adding a wildcard symbol may retrieve word variants: doc hieu lang - thanh trung cao dung ((cong san) or (cong tan)) than cap*.