Perhaps you should try some spelling variations:
doc hieu » hoc thieu, hoc hien
phan ung » phan xuong, phan cong
ung dang » dung dang, ung dung, duong dang
dang van » hoang van, hang va
van chat » cao chat
ung dat » dung dat, vung dat, cung dat
dat ung » dat dung, dat rung, dap ung
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 ung dat ung dang van van chat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (toc thieu)) tinh - phan ung dat ung dang van van chat.
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (toc thieu)) tinh - phan ung dat ung dang van van chat*.