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

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

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