Perhaps you should try some spelling variations:
canh trinh » canh tranh, hanh trinh, canh tinh
thien danh » thien anh, thien dang, thien thanh
hieu manh » chieu xanh, hieu nganh, dieu hanh
trinh chu » trinh cau, trinh cho, trinh thuc
bang cong » dang cong, bang song, hang cong
chu bang » thu bang, chuc nang, chu quang
cong san » cong tac
san toan » van toan, dan toan, manh toan
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 danh) or (hieu manh)) - canh trinh chu bang cong san toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc ((thien danh) OR (hieu manh)) - canh trinh chu bang cong san toan cau.
• Adding a wildcard symbol may retrieve word variants: hoc ((thien danh) or (hieu manh)) - canh trinh chu bang cong san toan cau*.