Perhaps you should try some spelling variations:
thanh phan » thanh pho, thanh san, thanh toan
hanh tranh » canh tranh, hanh trinh, hanh trang
hieu lang » chieu sang, hieu quang, nhieu tang
thanh cha » thanh ha, thanh nha, thanh pham
doc hieu » toc thieu, hoc thieu, hoc hien
cong tan » cong tac, cong san, cong thanh

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc hieu lang - hanh tranh ((cua ban) or (cua cong)) cong tan ((thanh cha) OR (thanh phan))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu lang - hanh tranh ((cua ban) OR (cua cong)) cong tan ((thanh cha) OR (thanh phan)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu lang - hanh tranh ((cua ban) or (cua cong)) cong tan ((thanh cha) OR (thanh phan))".
• Adding a wildcard symbol may retrieve word variants: doc hieu lang - hanh tranh ((cua ban) or (cua cong)) cong tan ((thanh cha) OR (thanh phan))*.