Perhaps you should try some spelling variations:
thanh trong » thanh trung, tranh trong, hanh trong
thien hach » thien thanh, hien hanh
hien sach » dien sach, kien sach, chieu sach
trong van » trong cac
dung cong » dung trong
van dung » van dong, xay dung, tin dung
cong tan » cong tac, cong san, cong thanh
tan van » tran van, tang van, luan van

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: hoc ((hien sach) or (thien hach)) - thanh trong van dung cong tan van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((hien sach) OR (thien hach)) - thanh trong van dung cong tan van ban.
• Adding a wildcard symbol may retrieve word variants: hoc ((hien sach) or (thien hach)) - thanh trong van dung cong tan van ban*.