Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
va triet » va thiet, ve triet, cua triet
van hanh » van thanh, ban hanh, van anh
lang xay » dang xay, luong xay, lang xuan
tac van » tac vang, cac van, tac va
cac tac » cac toc, cac bac, cac dac
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
sac ky » cac ky, sai ky
ve cac » va cac, vien cac
tu sac » tu sach, tu cac, tu san

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: tu sac ky ((lang xa) OR (lang xay)) hoi. hieu ve cac tac van hanh vi ((va triet) OR (va trien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((lang xa) or (lang xay)) hoi. hieu ve cac tac van hanh vi ((va triet) OR (va trien))~".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((lang xa) or (lang xay)) hoi. hieu ve cac tac van hanh vi ((va triet) OR (va trien))*.