Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
ban hanh » ban hang
sach lo » sach dao, sach doi, sach hoi
lo nang » ho nang, ly nang, loai nang
hieu ve » hieu va, hieu van
cua tre » cua te, cuu tre, cua triet
me hoi » le hoi
ve cac » va cac, vien cac
cac lo » cac lop, cac co, cac bo
lo ban » co ban, lo van, ly ban
vi cua » vai cua, di cua

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 lo nang ((me hoi) or (ma hoa)). hieu ve cac lo ban hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach lo nang ((me hoi) OR (ma hoa)). hieu ve cac lo ban hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach lo nang ((me hoi) or (ma hoa)). hieu ve cac lo ban hanh vi cua tre*.