Perhaps you should try some spelling variations:
trinh chuan » trinh han, trinh quan, trinh luan
thien thanh » tien thanh, thi thanh, hien hanh
hanh trinh » canh tranh, hanh chinh
chuan xang » chua xang, chuan trang, chua nang
cong van » cong vang, song van, cong tan
cong san » cong tac
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 ((thien thanh) or (tieng anh)) - hanh trinh chuan xang ((cong van) OR (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien thanh) OR (tieng anh)) - hanh trinh chuan xang ((cong van) OR (cong san)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc ((thien thanh) or (tieng anh)) - hanh trinh chuan xang ((cong van) OR (cong san)) toan cau".
• Adding a wildcard symbol may retrieve word variants: hoc ((thien thanh) or (tieng anh)) - hanh trinh chuan xang ((cong van) OR (cong san)) toan cau*.