Perhaps you should try some spelling variations:
chieu sach » chinh sach, chiet tach, chieu sang
hanh trang » thanh trung, canh tranh, hanh trinh
hieu manh » chieu xanh, hieu nganh, dieu hanh
trang va » tran van, hang va
cong van » cong vang, song van, cong tan
cong san » cong tac
toan cau » toan cao, toan ban, toan tap
va hang » van hang, va nang, va lang

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