Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, hang cong
hieu xanh » chieu xanh, hieu manh, hieu nganh
tranh cua » doanh cua, manh cua
cua nhung » va nhung
doc hieu » toc thieu, hoc thieu, hoc hien
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.

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu xanh - canh tranh cua nhung cong ((dan toan) or (dan than)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - canh tranh cua nhung cong ((dan toan) OR (dan than)) ban*.