Perhaps you should try some spelling variations:
lang trong » dung trong, cong trong, dong trong
phan cong » thanh cong
cong lang » cong vang, cong luong, cong quang
trong dan » trong dang, trong san, trong tan
doc hieu » hoc thieu, hoc hien
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)) tinh - phan cong lang trong dan van dan ca~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (toc thieu)) tinh - phan cong lang trong dan van dan ca*.