Perhaps you should try some spelling variations:
dang cong » dung cong
doc hieu » hoc thieu, hoc hien
phan dau » phan tu, hang dau
dau dang » da dang, dai dang, dau bang
cong dan » cong san, cong tan, huong dan
van chat » cao chat
dan van » dang van, doan van, dao van
van van » van ban, tan van, san 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) or (toc thieu)) tinh - phan dau dang cong dan van van chat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (toc thieu)) tinh - phan dau dang cong dan van van chat.
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (toc thieu)) tinh - phan dau dang cong dan van van chat*.