Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
va thanh » gia thanh, ban thanh, va tinh
thanh vi » hanh vi, thanh va, thanh ve
van dau » van dao, phan dau
dau xac » dau xay, dan xac
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
xac va » tac va, ac va, bac va
vi cua » vai cua, di cua
x hoi » o hoi, x ho, 5 hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y nang ((x hoi) or (xa hoi)). hieu van dau xac va thanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ((x hoi) OR (xa hoi)). hieu van dau xac va thanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ((x hoi) or (xa hoi)). hieu van dau xac va thanh vi cua tre*.