Perhaps you should try some spelling variations:
doi chieu » doi chi, ho chieu, mot chieu
hanh tran » hanh trang, thanh tran, hanh tram
van nhung » van nhuong, va nhung, van hung
doc hieu » toc thieu, hoc thieu, hoc hien
tran van » luan van
cong tan » cong tac, cong thanh, cong ty
cong san » cong tac
toan cau » toan cao, toan ban, toan tap

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 (doc hieu)) sach - hanh tran van nhung ((cong tan) OR (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((doi chieu) OR (doc hieu)) sach - hanh tran van nhung ((cong tan) OR (cong san)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((doi chieu) or (doc hieu)) sach - hanh tran van nhung ((cong tan) OR (cong san)) toan cau".
• Adding a wildcard symbol may retrieve word variants: ((doi chieu) or (doc hieu)) sach - hanh tran van nhung ((cong tan) OR (cong san)) toan cau*.