Perhaps you should try some spelling variations:
hanh tai » thanh tai, hang tai, han tai
tu sach » thu sach, su sach, te sach
tai cua » thai cua, tai cuc, tri cua
luc van » luoc van, luu van, duc van
xuc van » duc van, xuc ban, thuc van
cua tre » cua te, cuu tre, cua triet
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
co hoi » co hoc, co loi
ve cac » va cac, vien cac
o hoi » o hoc, o hai, o hoa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ((o hoi) OR (co hoi)). hieu ve cac ((xuc van) OR (luc van)) hanh tai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((o hoi) OR (co hoi)). hieu ve cac ((xuc van) or (luc van)) hanh tai cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((o hoi) OR (co hoi)). hieu ve cac ((xuc van) or (luc van)) hanh tai cua tre*.