Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
cau trieu » cac trieu, cau triet, chua trieu
dung cong » dung trong
co trieu » cac trieu, mot trieu, co hieu
trinh va » trinh van, trinh vat, trinh ve
dan toan » van toan, dan than, manh toan
va dung » van dung, va duong, vat dung

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((co trieu) OR (cau trieu)) tinh - canh trinh va dung cong ((dan toan) or (anh tuan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((co trieu) OR (cau trieu)) tinh - canh trinh va dung cong ((dan toan) OR (anh tuan)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((co trieu) OR (cau trieu)) tinh - canh trinh va dung cong ((dan toan) or (anh tuan)) cau".
• Adding a wildcard symbol may retrieve word variants: ((co trieu) OR (cau trieu)) tinh - canh trinh va dung cong ((dan toan) or (anh tuan)) cau*.