Perhaps you should try some spelling variations:
nhung cong » thong cong, hang cong, nhung don
hieu xanh » chieu xanh, hieu manh, hieu nganh
tranh cua » doanh cua, manh cua
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
dan toan » dan than, manh toan, xuan toan
van toan » van tuan, van tan, van thanh

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) or (dung cong)) ((dan toan) or (van toan)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - canh tranh cua ((nhung cong) OR (dung cong)) ((dan toan) OR (van toan)) cau.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - canh tranh cua ((nhung cong) or (dung cong)) ((dan toan) or (van toan)) cau*.