Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
doi chieu » doc hieu, doi chi, mot chieu
qua nhung » quan nhung, qua chung, chua nhung
cua nhung » va nhung
ho chieu » theo chieu, hoc thieu, mot chieu
cong dan » cong san, cong tan, huong dan
dan toan » van toan, dan than, manh toan
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: ((ho chieu) OR (doi chieu)) sach - hanh trinh ((qua nhung) or (cua nhung)) cong dan toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho chieu) OR (doi chieu)) sach - hanh trinh ((qua nhung) OR (cua nhung)) cong dan toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho chieu) OR (doi chieu)) sach - hanh trinh ((qua nhung) or (cua nhung)) cong dan toan cau".
• Adding a wildcard symbol may retrieve word variants: ((ho chieu) OR (doi chieu)) sach - hanh trinh ((qua nhung) or (cua nhung)) cong dan toan cau*.