Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, nhung don
hieu xanh » chieu xanh, hieu manh, hieu nganh
hanh doan » hanh doanh, thanh toan, thinh doan
hang cong » dang cong, hang nong, bang cong
trong van » trong cac
doc hieu » toc thieu, hoc thieu, hoc hien
tang van » dang van, hoang van, tang luan

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 - hanh doan va ((nhung cong) OR (hang cong)) ((tang van) OR (trong van)) ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - hanh doan va ((nhung cong) or (hang cong)) ((tang van) OR (trong van)) ban~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - hanh doan va ((nhung cong) or (hang cong)) ((tang van) OR (trong van)) ban*.