Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
nam thuc » nam thuoc, am thuc, nam thu
su sach » so sach, vu sach
nang ro » nang co, nang ho, nang ra
hieu va » lieu va, hieu qua
thuc va » thuc vat, thuc dan, thuc day
van dai » vanh dai, van dao, van hai
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang x
va nam » van nam, ha nam, va nay

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) OR (su sach)) ky ((nang o) OR (nang ro)) hoi. hieu va nam thuc va van dai cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (su sach)) ky ((nang o) OR (nang ro)) hoi. hieu va nam thuc va van dai cua tre~".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (su sach)) ky ((nang o) OR (nang ro)) hoi. hieu va nam thuc va van dai cua tre*.