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 cao » truong cao, trung cap, trung co
cao dung » cao dang, cao dong, cao ung
dan toan » dan than, manh toan, xuan toan
van toan » van tuan, van tan, van thanh

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 cao dung trong ((dan toan) OR (van toan)) cao~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((chieu sach) OR (hieu lang)) - thanh trung cao dung trong ((dan toan) OR (van toan)) cao.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((chieu sach) or (hieu lang)) - thanh trung cao dung trong ((dan toan) OR (van toan)) cao".
• Adding a wildcard symbol may retrieve word variants: hoc ((chieu sach) or (hieu lang)) - thanh trung cao dung trong ((dan toan) OR (van toan)) cao*.