Perhaps you should try some spelling variations:
cua viet » hoa viet, cua vat, cua dieu
ban hanh » ban hang
ca viet » va viet, co viet, hoa viet
duc ban » duc tan, duc van, dua ban
tang xa » trang xa, tang ma, lang xa
hanh di » hanh vi, hanh de, hang di
san ky » sang ky, van ky, ban ky
qua ca » qua cac, qua cua, qua cai
dan ky » van ky
ca duc » cao duc, cua duc, ca dua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((san ky) OR (dan ky)) tang xa hoi. hieu qua ca duc ban hanh di ((cua viet) or (ca viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((san ky) OR (dan ky)) tang xa hoi. hieu qua ca duc ban hanh di ((cua viet) OR (ca viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((san ky) OR (dan ky)) tang xa hoi. hieu qua ca duc ban hanh di ((cua viet) or (ca viet))".
• Adding a wildcard symbol may retrieve word variants: tu ((san ky) OR (dan ky)) tang xa hoi. hieu qua ca duc ban hanh di ((cua viet) or (ca viet))*.