Perhaps you should try some spelling variations:
theo chieu » theo tieu, theo chu, thi chieu
hang huong » hang thuong, hang luong, hoang phuong
huong cua » dung cua
dung cong » dung trong
ho chieu » hoc thieu, doi chieu, mot chieu
tap toan » tap doan, tap quan, bai toan
toan tap » toan ban

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: ((theo chieu) OR (ho chieu)) sach - hang huong cua ((dung cong) OR (trong cong)) tap toan tap~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((theo chieu) OR (ho chieu)) sach - hang huong cua ((dung cong) or (trong cong)) tap toan tap~".
• Adding a wildcard symbol may retrieve word variants: ((theo chieu) OR (ho chieu)) sach - hang huong cua ((dung cong) or (trong cong)) tap toan tap*.