Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
tu cach » tu cac
hieu va » lieu va, hieu qua
cau luc » cau truc, cau phuc
luc cap » suc cap, luc cao, luc canh
cap can » cap han, cap van, tap can
cua tre » cua te, cuu tre, cua triet
va cau » van cau, va cac, va dau
x hoi » xa hoi, x ho, 5 hoi
o hoi » co hoi, o hoc, o hai

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 cach) OR (thu sach)) ky nang ((x hoi) OR (o hoi)). hieu va cau luc cap can dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (thu sach)) ky nang ((x hoi) OR (o hoi)). hieu va cau luc cap can dai cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (thu sach)) ky nang ((x hoi) OR (o hoi)). hieu va cau luc cap can dai cua tre*.