Perhaps you should try some spelling variations:
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach y, sach ty
mai hoi » mai khoi, lai hoi, mai doi
dai hoi » dai hoc, dai hai, dai moi
cua tre » cua te, cuu tre, cua triet
ve cam » ve cham, ve cac, ve cai
va cam » va cham, va cac, va cao
xuc va » duc va, tuc va, luc va
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: su sach ky nang ((mai hoi) OR (dai hoi)). hieu ((ve cam) or (va cam)) xuc va hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((mai hoi) OR (dai hoi)). hieu ((ve cam) OR (va cam)) xuc va hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((mai hoi) OR (dai hoi)). hieu ((ve cam) or (va cam)) xuc va hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((mai hoi) OR (dai hoi)). hieu ((ve cam) or (va cam)) xuc va hanh vi cua tre*.