Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
anh xquang » anh quang, anh quan, anh xuan
doi chieu » doc hieu, doi chi, mot chieu
tran hung » tran hong, tran quang, tran hoang
hung cong » nhung cong, hung cuong, phung cong
tap toan » tap doan, bai toan
tap quan » tac quan, hai quan

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 - ((nhanh quang) OR (anh xquang)) tran hung cong ((tap toan) OR (tap quan)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doi chieu sach - ((nhanh quang) or (anh xquang)) tran hung cong ((tap toan) OR (tap quan)) cau~".
• Adding a wildcard symbol may retrieve word variants: doi chieu sach - ((nhanh quang) or (anh xquang)) tran hung cong ((tap toan) OR (tap quan)) cau*.