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
ve cham » va cham, ve chat, vu cham
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
san ky » sang ky, van ky, ban ky
ma hoi » xa hoi, ma hoa, me hoi
dan ky » van ky
vi cua » vai cua, di cua

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