Perhaps you should try some spelling variations:
hanh dai » hanh tai, hanh dao, vanh dai
van hanh » van thanh, ban hanh, van anh
su sach » so sach
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
vu sach » vu bach, vu khach
ve cac » va cac, vien cac
cac lo » cac lop, cac co, cac bo
lo van » le van, vo van, so van
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: ((su sach) OR (vu sach)) ky nang ((x hoi) OR (o hoi)). hieu ve cac lo van hanh dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) ky nang ((x hoi) OR (o hoi)). hieu ve cac lo van hanh dai cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) ky nang ((x hoi) OR (o hoi)). hieu ve cac lo van hanh dai cua tre*.