Perhaps you should try some spelling variations:
ban hanh » ban hang
giau cua » gian cua, gia cua, dieu cua
va thanh » gia thanh, ban thanh, va tinh
mai khoi » mai khoa, tai khoa, cac khoi
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
mai hoi » dai hoi, lai hoi, mai doi
bao bo » bac bo, ban bo, nao bo
va bao » va bai

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 (mai khoi)). hieu va bao bo ((ban hanh) or (va thanh)) giau cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ((mai hoi) OR (mai khoi)). hieu va bao bo ((ban hanh) OR (va thanh)) giau cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ((mai hoi) OR (mai khoi)). hieu va bao bo ((ban hanh) or (va thanh)) giau cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang ((mai hoi) OR (mai khoi)). hieu va bao bo ((ban hanh) or (va thanh)) giau cua tre*.