Perhaps you should try some spelling variations:
thanh hai » thanh phan, thanh hoa, thanh san
toc sach » doc sach, thuoc sach, nuoc sach
hoc sach » hoc sinh, hoc cac, hoc anh
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
luc va » duc va, loc va
tuc va » thuc va, truc va, tuc xa
v nang » va nang, vu nang, van nang
va cao » va cac, va co, va dao
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: ((toc sach) OR (hoc sach)) v nang x hoi. hieu va cao ((luc va) or (tuc va)) thanh hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((toc sach) OR (hoc sach)) v nang x hoi. hieu va cao ((luc va) OR (tuc va)) thanh hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((toc sach) OR (hoc sach)) v nang x hoi. hieu va cao ((luc va) or (tuc va)) thanh hai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((toc sach) OR (hoc sach)) v nang x hoi. hieu va cao ((luc va) or (tuc va)) thanh hai cua tre*.