Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
vanh dai » van dai, vanh tai, lanh dao
dai cuu » dai cua, dai huu
va vanh » va van, va danh, va hanh
cam tuc » cam xuc, cam tu, nam thuc
cuu tre » cua tre, cau tren, cau treo
sach ky » sac ky, sach y, sach ty
hieu va » lieu va
nang ro » nang co, nang ho, nang ra
tuc va » thuc va, truc va, tuc xa
nang o » nang co, nang ho, nang x

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: thu sach ky ((nang o) OR (nang ro)) hai. ((hieu va) OR (hieu qua)) cam tuc va vanh dai cuu tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ky ((nang o) or (nang ro)) hai. ((hieu va) OR (hieu qua)) cam tuc va vanh dai cuu tre~".
• Adding a wildcard symbol may retrieve word variants: thu sach ky ((nang o) or (nang ro)) hai. ((hieu va) OR (hieu qua)) cam tuc va vanh dai cuu tre*.