Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh tai » thanh tai, hang tai, han tai
ban hanh » ban hang
hieu ve » hieu va, hieu van
tai cua » thai cua, tai cuc, tri cua
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
y nang » ky nang, ly nang, v nang

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((te sach) OR (toc sach)) y nang ((me hoi) or (ma hoa)). hieu ve cac lo ban hanh tai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y nang ((me hoi) OR (ma hoa)). hieu ve cac lo ban hanh tai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y nang ((me hoi) or (ma hoa)). hieu ve cac lo ban hanh tai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y nang ((me hoi) or (ma hoa)). hieu ve cac lo ban hanh tai cua tre*.