Perhaps you should try some spelling variations:
cong trong » cong thuong, duong trong, cong trinh
trong dang » truong dang, trong dan, trong dong
phan dang » phan dau, phan cong, nhan dan
dang cong » dung cong
doc hieu » hoc thieu, hoc hien
dang van » hoang van, hang va
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)) tinh - phan dang cong trong dang van dan ca~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (toc thieu)) tinh - phan dang cong trong dang van dan ca*.