Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
ban hanh » ban hang
cham duc » cham soc, pham duy, phan duc
lang van » dang van, tang van, hoang van
hanh ki » hanh vi, hanh ky, hanh kien
tu dang » thu dang, tu dong, su dang
dang ky » dang y, dan ky, dong ky
lang xa » lang ha, dang xay
hieu ve » hieu va, hieu van
ki su » ky su

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu dang ky ((lang xa) or (lang van)) hoi. hieu ve ((cham duc) OR (pham duc)) ban hanh ki su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu dang ky ((lang xa) OR (lang van)) hoi. hieu ve ((cham duc) OR (pham duc)) ban hanh ki su triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu dang ky ((lang xa) or (lang van)) hoi. hieu ve ((cham duc) OR (pham duc)) ban hanh ki su triet*".