Perhaps you should try some spelling variations:
phuong cong » phuong dong, phong cong, phung cong
canh trinh » canh tranh, hanh trinh, canh tinh
va phuong » va thuong, cac phuong
ho chieu » theo chieu, hoc thieu, doi chieu
doc hieu » toc thieu, hoc thieu, hoc hien
trinh va » trinh van, trinh vat, trinh ve
dan toan » van toan, dan than, manh toan

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) OR (doc hieu)) sach - canh trinh va phuong cong ((dan toan) OR (dan gian)) tap~.
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) or (doc hieu)) sach - canh trinh va phuong cong ((dan toan) or (dan gian)) tap*.