Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sach » chinh sach, chiet tach, chieu sang
hieu quan » hieu qua, lieu quan, thien quan
trung cua » truong cua, trung tuan, trung cap
dung cong » dung trong
cua dung » cua dang, cua dong, qua dung
tac tuan » ta tuan, tai tuan, tac tuyen

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho ((chieu sach) or (hieu quan)) - thanh trung cua dung cong ((tac tuan) OR (tac quan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho ((chieu sach) OR (hieu quan)) - thanh trung cua dung cong ((tac tuan) OR (tac quan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sach) or (hieu quan)) - thanh trung cua dung cong ((tac tuan) OR (tac quan)) cao".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sach) or (hieu quan)) - thanh trung cua dung cong ((tac tuan) OR (tac quan)) cao*.