Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
theo cau » theo chu, theo cap, theo dau
cau sach » cao sach, hau sach, rau sach
dan toan » van toan, manh toan, xuan toan
dan than » dan chan, ban than, van than
va dang » van dang, va nang, da dang
va lang » va nang, hoa lang

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 cau sach - hanh trinh ((va dang) OR (va lang)) cong ((dan toan) OR (dan than)) cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo cau sach - hanh trinh ((va dang) OR (va lang)) cong ((dan toan) or (dan than)) cau~".
• Adding a wildcard symbol may retrieve word variants: theo cau sach - hanh trinh ((va dang) OR (va lang)) cong ((dan toan) or (dan than)) cau*.