Perhaps you should try some spelling variations:
trung tuan » trung thanh, trung tam, tran tuan
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung cap, dung cua
doc hieu » toc thieu, hoc thieu, hoc hien
cong tan » cong san, cong thanh, cong ty
cong tac » cong ty
toan cao » toan ban, toan tap

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 cua) or (trung tuan)) dung ((cong tan) OR (cong tac)) toan cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - thanh ((trung cua) OR (trung tuan)) dung ((cong tan) OR (cong tac)) toan cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu lang - thanh ((trung cua) or (trung tuan)) dung ((cong tan) OR (cong tac)) toan cao".
• Adding a wildcard symbol may retrieve word variants: doc hieu lang - thanh ((trung cua) or (trung tuan)) dung ((cong tan) OR (cong tac)) toan cao*.