Perhaps you should try some spelling variations:
trinh luan » trinh luat, trinh quan, trinh toan
bien tinh » bi tinh, yen tinh, diep tinh
trinh han » trinh quan
cong dan » cong tan, huong dan, cong dong
cong san » cong tac
than tap » toan tap, han tap, phan tap
ho bien » pho bien, hoa bien, so bien

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

• Performing a fuzzy search may retrieve terms with similar spellings: ho bien tinh - hanh ((trinh luan) OR (trinh han)) phung ((cong dan) or (cong san)) than tap~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ho bien tinh - hanh ((trinh luan) OR (trinh han)) phung ((cong dan) OR (cong san)) than tap.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ho bien tinh - hanh ((trinh luan) OR (trinh han)) phung ((cong dan) or (cong san)) than tap".
• Adding a wildcard symbol may retrieve word variants: ho bien tinh - hanh ((trinh luan) OR (trinh han)) phung ((cong dan) or (cong san)) than tap*.