Perhaps you should try some spelling variations:
thanh thai » thanh hai, thanh tai, nhanh thai
thai cua » than cua, tai cuc, tri cua
te sach » toc sach
can ban » van ban, toan ban
cac ban » cac dan, cac van, cac bai
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
van hoe » van hoa, van hoc, van hieu
van hoi » van hoa, van hoc, van loi
sach o » sach lo, sac o, sach y
o lang » hoa lang, hoi lang
va cam » va cham, va cac, va cao

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: te sach o lang ((van hoi) OR (van hoe)). hieu va cam ((cac ban) OR (can ban)) thanh thai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach o lang ((van hoi) or (van hoe)). hieu va cam ((cac ban) OR (can ban)) thanh thai cua tre~".
• Adding a wildcard symbol may retrieve word variants: te sach o lang ((van hoi) or (van hoe)). hieu va cam ((cac ban) OR (can ban)) thanh thai cua tre*.