Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hanh trang » thanh trung, canh tranh, hanh trinh
chan hong » phan hong, chan thuong, chau phong
chun hong » chung thong, china hong, cheng hong
mai toan » bai toan, mai tan, mai loan
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: hoc ((dieu hanh) or (chieu sach)) - hanh trang ((chan hong) OR (chun hong)) thuong mai toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((dieu hanh) OR (chieu sach)) - hanh trang ((chan hong) OR (chun hong)) thuong mai toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((dieu hanh) or (chieu sach)) - hanh trang ((chan hong) OR (chun hong)) thuong mai toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((dieu hanh) or (chieu sach)) - hanh trang ((chan hong) OR (chun hong)) thuong mai toan cau*.