Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
trinh dau » trinh cau, trinh da, trinh dan
bang cong » dang cong, bang song, hang cong
theo chu » theo chieu, cho chu, chao chu
dau bang » dau quang, dang bang, cao bang
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
toan cau » toan cao, toan ban, toan 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: ((theo chu) OR (theo tieu)) sach - canh trinh dau bang cong dan toan cau~.
• Adding a wildcard symbol may retrieve word variants: ((theo chu) or (theo tieu)) sach - canh trinh dau bang cong dan toan cau*.