Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hieu quang » thieu quang, hieu quan, hieu qua
dung cong » dung trong
tap toan » tap doan, bai toan
tap quan » tac quan, hai quan
cong va » dong va, cong ha, cong tac
va dung » van dung, va duong, vat dung

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: ho ((chieu sach) OR (hieu quang)) - thanh cong va dung cong ((tap toan) OR (tap quan)) cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho ((chieu sach) or (hieu quang)) - thanh cong va dung cong ((tap toan) OR (tap quan)) cao~".
• Adding a wildcard symbol may retrieve word variants: ho ((chieu sach) or (hieu quang)) - thanh cong va dung cong ((tap toan) OR (tap quan)) cao*.