Perhaps you should try some spelling variations:
theo dong » theo duong, theo cong, theo don
hanh tang » hanh trang, anh tang, hanh mang
hang cong » dang cong, hang nong, bang cong
theo doi » theo duoi, theo don, thay doi
tang cua » mang cua, hang cua, tang luan
cua hang » cua dang, cua nhung, cua cong
dan toan » van toan, manh toan, xuan toan
dan than » dan chan, ban than, van than

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 doi) OR (theo dong)) tinh - hanh tang cua hang cong ((dan toan) OR (dan than)) cao~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((theo doi) OR (theo dong)) tinh - hanh tang cua hang cong ((dan toan) or (dan than)) cao~".
• Adding a wildcard symbol may retrieve word variants: ((theo doi) OR (theo dong)) tinh - hanh tang cua hang cong ((dan toan) or (dan than)) cao*.