Perhaps you should try some spelling variations:
thanh trung » thanh tung
chieu sach » chinh sach, chiet tach, chieu sang
doi chieu » doc hieu, doi chi, ho chieu
trung can » trung cap, trung van, trong can
bang cong » dang cong, bang song, hang cong
can bang » cao bang, can ban, van ban
tac toan » tap toan, tam toan, hach toan
bai toan » bai 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 - thanh trung can bang cong ((tac toan) or (bai toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doi chieu sach - thanh trung can bang cong ((tac toan) OR (bai toan)) cau.
• Adding a wildcard symbol may retrieve word variants: doi chieu sach - thanh trung can bang cong ((tac toan) or (bai toan)) cau*.