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
doc hieu » toc thieu, hoc thieu, hoc hien
nhung bo » nhung bi, nhung bai, nhung don
dan than » dan chan, ban than, van than
than cau » toan cau, phan cau, than cap

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 ((((nhung cong) OR (nhung bo))) OR (trong cong)) dan than cau~.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - canh tranh cua ((((nhung cong) or (nhung bo))) or (trong cong)) dan than cau*.