Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
thanh tung » thanh cong
hieu lang » chieu sang, hieu quang, nhieu tang
cua trong » cua truong, cua trung, qua trong
tung cua » trung cua, tuong cua, dung cua
cong tan » cong san, cong thanh, cong ty
cong tac » cong ty
tran tap » toan tap, tran tan, tran tuan

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

• Performing a fuzzy search may retrieve terms with similar spellings: doi ((hieu lang) or (chieu sach)) - thanh tung cua trong ((cong tan) or (cong tac)) tran tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((hieu lang) OR (chieu sach)) - thanh tung cua trong ((cong tan) OR (cong tac)) tran tap.
• Adding a wildcard symbol may retrieve word variants: doi ((hieu lang) or (chieu sach)) - thanh tung cua trong ((cong tan) or (cong tac)) tran tap*.