Perhaps you should try some spelling variations:
nhung cong » dung cong, thong cong, nhung don
hieu xanh » chieu xanh, hieu manh, hieu nganh
tranh cua » doanh cua, manh cua
hang cong » dang cong, hang nong, bang cong
doc hieu » toc thieu, hoc thieu, hoc hien
chan cau » phan cau, chinh cau, nhanh cau
can cau » van cau, ban cau, ca cau

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 (hang cong)) dan ((chan cau) OR (can cau))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - canh tranh cua ((nhung cong) or (hang cong)) dan ((chan cau) OR (can cau))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - canh tranh cua ((nhung cong) or (hang cong)) dan ((chan cau) OR (can cau))*.