Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
cao hoi » cau hoi, cao hoc, tao hoi
hieu va » lieu va, hieu qua
cac xuc » cam xuc, cac nuoc, chat xuc
cua tre » cua te, cuu tre, cua triet
co hoi » co hoc, co loi
xuc va » duc va, tuc va, luc va

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 ((cao hoi) OR (co hoi)). hieu va cac xuc va ((danh cho) OR (dan ca)) cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ((cao hoi) OR (co hoi)). hieu va cac xuc va ((danh cho) or (dan ca)) cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ((cao hoi) OR (co hoi)). hieu va cac xuc va ((danh cho) or (dan ca)) cua tre*.