Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
thong cong » trong cong, tong cong, phong chong
tieu sach » chieu sach, dien sach, te sach
trinh va » trinh van, trinh vat, trinh ve
van toan » van tuan, van tan, van thanh
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 tieu sach - canh trinh va ((thong cong) OR (thong thong)) van toan cau~.
• Adding a wildcard symbol may retrieve word variants: theo tieu sach - canh trinh va ((thong cong) or (thong thong)) van toan cau*.