Perhaps you should try some spelling variations:
dung cong » dung trong
hieu xanh » chieu xanh, hieu manh, hieu nganh
doc hieu » toc thieu, hoc thieu, hoc hien
anh sang » lanh sang, anh bang, anh nang
anh dang » anh dong, anh dung, anh bang
cong dan » cong san, cong tan, huong dan
va dung » van dung, va duong, vat dung
dan van » dang van, doan van, dao van

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 xanh - ((anh sang) or (anh dang)) va dung cong dan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu xanh - ((anh sang) OR (anh dang)) va dung cong dan van ban.
• Adding a wildcard symbol may retrieve word variants: doc hieu xanh - ((anh sang) or (anh dang)) va dung cong dan van ban*.