Perhaps you should try some spelling variations:
viet sach » viet anh, dien sach, viet tech
tranh cua » doanh cua, manh cua
cua trong » cua truong, cua trung, qua trong
cong san » cong tac
san toan » van toan, dan toan, manh toan
toan cau » toan cao, toan ban, toan tap
te sach » toc sach

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 ((viet sach) OR (te sach)) - canh tranh cua trong cong san toan cau~.
• Adding a wildcard symbol may retrieve word variants: theo ((viet sach) or (te sach)) - canh tranh cua trong cong san toan cau*.