Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh vi » hanh vi, thanh va, thanh ve
sach thu » sach thue, sach thieu, sach tham
hieu va » lieu va
cua tre » cua te, cuu tre, cua triet
sach ty » sach y, sach tu, xach tay
xu ban » xuc ban, tu ban, vu ban
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ty) or (sach thu)) nang x hoi. ((hieu va) or (hieu qua)) chao xu ban thanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach thu)) nang x hoi. ((hieu va) OR (hieu qua)) chao xu ban thanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: tu ((sach ty) or (sach thu)) nang x hoi. ((hieu va) or (hieu qua)) chao xu ban thanh vi cua tre*.