Perhaps you should try some spelling variations:
doi chieu » doc hieu, ho chieu, mot chieu
canh tran » canh tranh, hanh trang, banh trang
van nhung » van nhuong, va nhung, van hung
tran van » luan van
cong tan » cong tac, cong thanh, cong ty
cong san » cong tac
doi chi » doi khi

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((doi chieu) or (doi chi)) sach - canh tran van nhung ((cong tan) or (cong san)) van ban~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (doi chi)) sach - canh tran van nhung ((cong tan) OR (cong san)) van ban.
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) or (doi chi)) sach - canh tran van nhung ((cong tan) or (cong san)) van ban*.