Perhaps you should try some spelling variations:
dung cong » dung trong
doc hieu » hoc thieu, hoc hien
cong dat » cong dan, dong dat, cong da
dat dung » dan dung, vat dung, da dung
cong tan » cong tac, cong san, cong thanh
tan van » tran van, tang van, luan van
van tan » van tuan, van ban, van tai

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 - thanh cong dat dung cong tan van tan~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doc hieu) OR (toc thieu)) tinh - thanh cong dat dung cong tan van tan.
• Adding a wildcard symbol may retrieve word variants: ((doc hieu) or (toc thieu)) tinh - thanh cong dat dung cong tan van tan*.