Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
vai cua » dai cua, hai cua, lai cua
dao vai » dao van, dao va, dao bai
cac toc » cac toi, cac nuoc, cac thoi
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu van
ky dang » ky nang, ky danh
ky tang » ky nang, kho tang, ky trong
ma hoi » mai hoi, xa hoi, ma hoa
toc va » hoc va, toc ta, tuc va
va dao » ca dao

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: tu sach ((ky tang) OR (ky dang)) ma hoi. ((hieu ve) OR (hieu va)) cac toc va dao vai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky tang) OR (ky dang)) ma hoi. ((hieu ve) or (hieu va)) cac toc va dao vai cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky tang) OR (ky dang)) ma hoi. ((hieu ve) or (hieu va)) cac toc va dao vai cua tre*.