Perhaps you should try some spelling variations:
doc hieu » hoc thieu, hoc hien
cong ung » cong dung, cong hung, cung ung
dan dung » van dung, tin dung, ap dung
dung dan » dung dat, dung san, tung dan
ung dan » tung dan, bung dan, hung dan
dan van » dang van, doan van, dao van
van dan » van ban, ban dan, van dao

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)) sang - cong ung dan dung dan van dan ca~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (toc thieu)) sang - cong ung dan dung dan van dan ca*.