Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sach » chinh sach, chiet tach, chieu sang
hieu lang » chieu sang, hieu quang, nhieu tang
trung cua » truong cua, trung tuan, trung cap
bang cong » dang cong, bang song, hang cong
cua bang » chua bang, cua ban, cua dang
cong tan » cong tac, cong san, cong thanh
than cau » phan cau, than cap, thanh chau
toan cau » 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: doi ((chieu sach) or (hieu lang)) - thanh trung cua bang cong tan ((than cau) or (toan cau))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi ((chieu sach) OR (hieu lang)) - thanh trung cua bang cong tan ((than cau) OR (toan cau)).
• Adding a wildcard symbol may retrieve word variants: doi ((chieu sach) or (hieu lang)) - thanh trung cua bang cong tan ((than cau) or (toan cau))*.