Perhaps you should try some spelling variations:
hieu sang » chieu sang, hieu lang, hieu quang
chua bang » chu bang, chua nang, chua xang
doc hieu » toc thieu, hoc thieu, hoc hien
cua bang » cua ban, cua dang, cua hang
cong dan » cong san, cong tan, huong dan
phan dau » phan tu
hang dau » hang va, hang tai

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