Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
te sach » toc sach
hoc cac » hoc cao
qua cam » qua cham, qua cac, qua ca
cam duc » cam xuc, cao duc, pham duc
duc van » duc va, duc tan, duc manh
hanh di » hanh vi, hanh de, hang di
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua
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: ((te sach) OR (hoc cac)) ky nang ((x hoi) OR (o hoi)). hieu qua cam duc van hanh di cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) or (hoc cac)) ky nang ((x hoi) OR (o hoi)). hieu qua cam duc van hanh di cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (hoc cac)) ky nang ((x hoi) OR (o hoi)). hieu qua cam duc van hanh di cua tre*.