Perhaps you should try some spelling variations:
duong thanh » dong thanh, muong thanh, dung thanh
luong thanh » muong thanh, truong thanh, dong thanh
theo chieu » theo tieu, ho chieu, theo chu
chieu sach » chinh sach, chiet tach, chieu sang
hanh trinh » canh tranh, hanh chinh
cong ban » cong bang, cong tan, cong dan
cong san » cong tac
hanh cau » nhanh cau, hang cau, hanh cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: theo chieu sach - hanh trinh ((duong thanh) OR (luong thanh)) ((cong ban) or (cong san)) hanh cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: theo chieu sach - hanh trinh ((duong thanh) OR (luong thanh)) ((cong ban) OR (cong san)) hanh cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "theo chieu sach - hanh trinh ((duong thanh) OR (luong thanh)) ((cong ban) or (cong san)) hanh cau".
• Adding a wildcard symbol may retrieve word variants: theo chieu sach - hanh trinh ((duong thanh) OR (luong thanh)) ((cong ban) or (cong san)) hanh cau*.