Perhaps you should try some spelling variations:
cham duc » pham duc, pham duy, phan duc
ban hanh » ban hang
mai hoi » mai khoi, dai hoi, lai hoi
hieu vu » hieu va, hieu ve, hieu su
cua tre » cua te, cuu tre, cua triet
tu bai » tu ban, tu bat, te bai
bai ky » ban ky, sai ky, bac 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 bai ky nang ((xa hoi) or (mai hoi)). hieu vu ((cham duc) OR (cham soc)) ban hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu bai ky nang ((xa hoi) OR (mai hoi)). hieu vu ((cham duc) OR (cham soc)) ban hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu bai ky nang ((xa hoi) or (mai hoi)). hieu vu ((cham duc) OR (cham soc)) ban hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu bai ky nang ((xa hoi) or (mai hoi)). hieu vu ((cham duc) OR (cham soc)) ban hanh vi cua tre*.