Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
van dinh » van minh, van dich, xuan dinh
viet cua » viec cua, viet ca, viet qua
sach ty » sach y, sach tu, sach thu
mai hoi » mai khoi, dai hoi, lai hoi
hieu va » lieu va, hieu qua
va dinh » va kinh, va tinh, vu dinh
cua tre » cua te, cuu tre, cua triet
ma hoi » xa hoi, ma hoa, me hoi

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: thuoc sach ty xang ((ma hoi) OR (mai hoi)). hieu va cac du ((va dinh) OR (van dinh)) viet cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ty xang ((ma hoi) or (mai hoi)). hieu va cac du ((va dinh) OR (van dinh)) viet cua tre~".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ty xang ((ma hoi) or (mai hoi)). hieu va cac du ((va dinh) OR (van dinh)) viet cua tre*.