Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
ky tang » ky nang, ky dang, kho tang
tang xa » trang xa, tang ma, lang xa
van cau » van dau, van hau, van chat
sach ky » sac ky, sach y, sach ty
tai cua » thai cua, tai cuc, dai cua
truc va » thuc va, thuc vat, trung va
tuc va » thuc va, tuc xa, duc va

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: toc sach ky tang xa hoi. hieu van cau ((tuc va) OR (truc va)) thanh ((tai cua) OR (tri cua)) te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky tang xa hoi. hieu van cau ((tuc va) OR (truc va)) thanh ((tai cua) or (tri cua)) te~".
• Adding a wildcard symbol may retrieve word variants: toc sach ky tang xa hoi. hieu van cau ((tuc va) OR (truc va)) thanh ((tai cua) or (tri cua)) te*.