Perhaps you should try some spelling variations:
thanh trung » thanh tung
hieu lang » chieu sang, hieu quang, nhieu tang
hoc hieu » hoc thieu, hoc hien, doc hieu
trung va » truong va, trang va, trung ha
cong ban » cong bang, cong san, cong tan
cong tac » cong ty
than cau » toan cau, than cap, thanh chau
phan cau » phan dau, phan cac, phan tu
va dung » van dung, va duong, vat dung

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: hoc hieu lang - thanh trung va dung ((cong ban) OR (cong tac)) ((than cau) OR (phan cau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc hieu lang - thanh trung va dung ((cong ban) or (cong tac)) ((than cau) OR (phan cau))~".
• Adding a wildcard symbol may retrieve word variants: hoc hieu lang - thanh trung va dung ((cong ban) or (cong tac)) ((than cau) OR (phan cau))*.