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 can » trung cap, trung van, trong can
cong cong » cong dong, trong cong, dung cong
can cong » cac cong, cao cong, van cong
cong san » cong tac
san van » tan van, luan van, tran van

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((chieu sach) or (hieu lang)) - thanh trung can cong cong san van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (hieu lang)) - thanh trung can cong cong san van ban.
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (hieu lang)) - thanh trung can cong cong san van ban*.