Perhaps you should try some spelling variations:
cham dua » cham giua, pham duc, pham duy
ban hanh » ban hang
mai hoi » mai khoi, dai hoi, lai hoi
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
tu van » tu va
ma hoi » xa hoi, ma hoa, me hoi
vi cua » vai cua, di cua

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