Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sach » chinh sach, chiet tach, chieu sang
hieu sach » hieu cach, dien sach, hieu cac
dung cong » dung trong
tam dung » tam duong, tac dung, tan dung
cong tan » cong tac, cong san, cong thanh
tan than » tan thanh, tan tran, ban than
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 sach) or (chieu sach)) - thanh trung tam dung cong tan than cap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc ((hieu sach) OR (chieu sach)) - thanh trung tam dung cong tan than cap.
• Adding a wildcard symbol may retrieve word variants: doc ((hieu sach) or (chieu sach)) - thanh trung tam dung cong tan than cap*.