Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
thanh de » hanh de, thanh ve, thanh do
van nang » van quang, van ban, van dong
truc van » truc va, thuc van, truc ban
so sach » bo sach, co sach, hoc sach
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
so sanh » do sanh
ve cau » ke cau, va cau, ve cac
de cuu » de cua
o hoc » co hoc, mo hoc, so hoc
o hoi » co hoi, o hai, o hoa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: ((so sach) OR (so sanh)) van nang ((o hoi) or (o hoc)). hieu ve cau truc van thanh de cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((so sach) OR (so sanh)) van nang ((o hoi) OR (o hoc)). hieu ve cau truc van thanh de cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((so sach) OR (so sanh)) van nang ((o hoi) or (o hoc)). hieu ve cau truc van thanh de cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((so sach) OR (so sanh)) van nang ((o hoi) or (o hoc)). hieu ve cau truc van thanh de cuu tre*.