Perhaps you should try some spelling variations:
hieu sach » chieu sach, hieu cach, dien sach
hanh tran » hanh trang, thanh tran, hanh tram
hung cong » nhung cong, hung cuong, phung cong
doc hieu » toc thieu, hoc thieu, hoc hien
tran van » luan van
van hung » van dung, manh hung, van duong
dan toan » van toan, dan than, manh toan
ban hang » ngan hang

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 sach - hanh tran van hung cong ((dan toan) or (ban hang)) ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc hieu sach - hanh tran van hung cong ((dan toan) OR (ban hang)) ban.
• Adding a wildcard symbol may retrieve word variants: doc hieu sach - hanh tran van hung cong ((dan toan) or (ban hang)) ban*.