Perhaps you should try some spelling variations:
ban hanh » ban hang
ky dang » ky nang, ky danh
dang ma » dang mau, dang mam, dang mat
hieu ve » hieu va, hieu van
cham so » cham o, ham so, cham hoi
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
ma hoi » mai hoi, xa hoi, ma hoa

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 cac ky dang ma hoi. hieu ve ((cham so) OR (cham soc)) ban hanh vi ((cua tre) OR (cuu tre))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky dang ma hoi. hieu ve ((cham so) or (cham soc)) ban hanh vi ((cua tre) OR (cuu tre))~".
• Adding a wildcard symbol may retrieve word variants: tu cac ky dang ma hoi. hieu ve ((cham so) or (cham soc)) ban hanh vi ((cua tre) OR (cuu tre))*.