Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
tranh cua » doanh cua, manh cua
manh toan » thanh toan, anh tuan, tinh toan
doc hieu » toc thieu, hoc thieu, hoc hien
cua dung » cua dang, cua dong, qua dung
dan toan » van toan, xuan toan, dien 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: doc hieu xanh - canh tranh cua dung trong ((((dan toan) OR (manh toan))) OR (dan than)) cao~.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - canh tranh cua dung trong ((((dan toan) or (manh toan))) or (dan than)) cao*.