Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
dang xay » dang van, van xay
va viet » hoa viet, san viet, mai viet
tinh vi » trinh vi, tinh voi, tinh va
loc may » hoc may, loc mau, loai may
cac loc » cac lop, cac toc, cac hoc
hieu ve » hieu va, hieu van
lang xa » lang ha, lang van
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
so sac » so sach, so dac

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

• If you are trying to use Boolean operators, they must be ALL CAPS: so sac ky ((lang xa) OR (dang xay)) hoi. hieu ve cac loc may tinh vi ((cua viet) OR (va viet))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sac ky ((lang xa) OR (dang xay)) hoi. hieu ve cac loc may tinh vi ((cua viet) or (va viet))~".
• Adding a wildcard symbol may retrieve word variants: so sac ky ((lang xa) OR (dang xay)) hoi. hieu ve cac loc may tinh vi ((cua viet) or (va viet))*.