Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
trinh su » trinh tu, trinh san, trinh cau
cong dan » cong san, huong dan, cong dong
cong tan » cong tac, cong san, cong thanh
chan cau » phan cau, can cau, chinh cau
ho lieu » co lieu, ho kieu, ho chieu
so lieu » so dieu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: ((ho lieu) OR (so lieu)) tinh - hanh trinh su dung ((cong dan) OR (cong tan)) chan cau~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((ho lieu) OR (so lieu)) tinh - hanh trinh su dung ((cong dan) or (cong tan)) chan cau~".
• Adding a wildcard symbol may retrieve word variants: ((ho lieu) OR (so lieu)) tinh - hanh trinh su dung ((cong dan) or (cong tan)) chan cau*.