Perhaps you should try some spelling variations:
doi chieu » doi chi, ho chieu, mot chieu
tranh xay » trinh xay, manh xay, nganh xay
trong xay » thong xay, trong cac, trong ca
dung cong » dung trong
doc hieu » toc thieu, hoc thieu, hoc hien
cong san » cong tac
san than » sang than, san thanh, ban than
than ban » thanh ban, toan ban, than man

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