Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hanh trung » thanh trung, hanh trang, manh trung
trung tuan » trung thanh, trung tam, tran tuan
doi chieu » doc hieu, doi chi, ho chieu
tong cong » cong cong, dung cong, dang cong
tap toan » tap doan, tap quan
bai toan » bai tap

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

• If you are trying to use Boolean operators, they must be ALL CAPS: doi chieu sach - hanh trung tuan ((tong cong) OR (trong cong)) ((tap toan) OR (bai toan)) ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi chieu sach - hanh trung tuan ((tong cong) or (trong cong)) ((tap toan) OR (bai toan)) ban~".
• Adding a wildcard symbol may retrieve word variants: doi chieu sach - hanh trung tuan ((tong cong) or (trong cong)) ((tap toan) OR (bai toan)) ban*.