Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
doi chieu » doi chi, ho chieu, mot chieu
trinh xay » trinh ky
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
dan than » dan chan, ban than, dan toan
van than » van thanh, van thang, van tuan

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: ((doi chieu) OR (doc hieu)) sang - canh trinh xay dung cong ((dan than) OR (van than)) ban~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) or (doc hieu)) sang - canh trinh xay dung cong ((dan than) OR (van than)) ban~".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) or (doc hieu)) sang - canh trinh xay dung cong ((dan than) OR (van than)) ban*.