Perhaps you should try some spelling variations:
ban hanh » ban hang
cham duc » pham duc, cham soc, pham duy
cua tre » cua te, cuu tre, cua triet
duc ban » duc tan, duc van, dua ban
vu cham » va cham, vu kham, tu cham
hieu vu » hieu va, hieu ve, hieu su
mai hoi » mai khoi, dai hoi, lai hoi
bai ky » ban ky, sai ky, bac ky
ma hoi » xa hoi, me hoi, va hoi
vi cua » vai cua, di cua
tu bai » tu ban, tu bat, te bai

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu bai ky nang ((((ma hoi) OR (ma hoa))) or (mai hoi)). hieu vu cham duc ban hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu bai ky nang ((((ma hoi) OR (ma hoa))) OR (mai hoi)). hieu vu cham duc ban hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu bai ky nang ((((ma hoi) OR (ma hoa))) or (mai hoi)). hieu vu cham duc ban hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu bai ky nang ((((ma hoi) OR (ma hoa))) or (mai hoi)). hieu vu cham duc ban hanh vi cua tre*.