Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
hanh vai » hanh vi, hanh va, hanh tai
dang van » hoang van, hang va
vai cua » dai cua, hai cua, lai cua
duy van » duy vat, dung van
duy ban » uy ban, duy can, dua ban
tu dang » thu dang, tu dong, su dang
dang ky » dang y, dan ky, dong ky
lang xa » lang ha, dang xay, lang van
hieu v » hieu va, hieu ve, hieu 2
v pham » vi pham, d pham

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 (dang van)) hoi. hieu v pham ((duy ban) OR (duy van)) hanh vai cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu dang ky ((lang xa) OR (dang van)) hoi. hieu v pham ((duy ban) OR (duy van)) hanh vai cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu dang ky ((lang xa) or (dang van)) hoi. hieu v pham ((duy ban) OR (duy van)) hanh vai cua viet".
• Adding a wildcard symbol may retrieve word variants: tu dang ky ((lang xa) or (dang van)) hoi. hieu v pham ((duy ban) OR (duy van)) hanh vai cua viet*.