Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
van nang » van quang, van ban, van dong
truc van » truc va, thuc van, truc ban
su bach » vu bach, huu bach, cua bach
hanh de » hanh ve, hanh kem
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
su sach » so sach, vu sach
ve cau » ke cau, va cau, ve cac
de cua » le cua, te cua, dieu 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: ((su bach) OR (su sach)) van nang ((x hoi) OR (o hoi)). hieu ve cau truc van hanh de cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su bach) or (su sach)) van nang ((x hoi) OR (o hoi)). hieu ve cau truc van hanh de cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((su bach) or (su sach)) van nang ((x hoi) OR (o hoi)). hieu ve cau truc van hanh de cua tre*.