Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
thanh di » thanh doi, thanh de, thanh do
tu cach » tu cac
te sach » toc sach
van cam » van nam, van lam, van cau
cam duc » cam xuc, cao duc, pham duc
duc ban » duc tan, duc van, dua ban
cua tre » cua te, cuu tre, cua triet
di cua » dai cua, doi cua, de cua
x hoi » xa hoi, o hoi, 5 hoi

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 (te sach)) ky nang ((x hoi) OR (x ho)). hieu van cam duc ban thanh di cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu cach) or (te sach)) ky nang ((x hoi) OR (x ho)). hieu van cam duc ban thanh di cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((tu cach) or (te sach)) ky nang ((x hoi) OR (x ho)). hieu van cam duc ban thanh di cua tre*.