Perhaps you should try some spelling variations:
hieu xanh » chieu xanh, hieu manh, hieu nganh
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
cong san » cong tac
cong va » dong va, cong tac, luong va
cong ha » cong hoa, dong ha, cong tac
hang ca » hang va, hang tai, hang dau

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 - thanh ((cong va) OR (cong ha)) dung cong san ((hang ca) OR (nang cao))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu xanh - thanh ((cong va) or (cong ha)) dung cong san ((hang ca) OR (nang cao))~".
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - thanh ((cong va) or (cong ha)) dung cong san ((hang ca) OR (nang cao))*.