Perhaps you should try some spelling variations:
hanh truong » hanh trong, anh truong, manh truong
truong cao » truong dai
hieu sang » chieu sang, hieu lang, hieu quang
cao nhung » cho nhung, cam nhung, cao chung
doc hieu » toc thieu, hoc thieu, hoc hien
cong dan » cong tan, huong dan, cong tac
cong san » cong tac

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 sang - hanh truong cao nhung ((((cong dan) OR (cong san))) or (cong dong)) thanh san~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sang - hanh truong cao nhung ((((cong dan) OR (cong san))) OR (cong dong)) thanh san.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc hieu sang - hanh truong cao nhung ((((cong dan) OR (cong san))) or (cong dong)) thanh san".
• Adding a wildcard symbol may retrieve word variants: doc hieu sang - hanh truong cao nhung ((((cong dan) OR (cong san))) or (cong dong)) thanh san*.