Perhaps you should try some spelling variations:
chiet tach » chieu sach
trinh hanh » trinh thanh, trinh anh, trinh hinh
trinh han » trinh quan
ho chiet » ho chieu, ho thiet, hoc thiet
cong tan » cong tac, cong thanh, cong ty
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: ho chiet tach - hanh ((trinh hanh) OR (trinh han)) nhung ((cong tan) or (cong san)) toan cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho chiet tach - hanh ((trinh hanh) OR (trinh han)) nhung ((cong tan) OR (cong san)) toan cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho chiet tach - hanh ((trinh hanh) OR (trinh han)) nhung ((cong tan) or (cong san)) toan cau".
• Adding a wildcard symbol may retrieve word variants: ho chiet tach - hanh ((trinh hanh) OR (trinh han)) nhung ((cong tan) or (cong san)) toan cau*.