Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cac thuc » cach thuc, cac thu, can thuc
su sach » vu sach
so sach » so sanh, bo sach, co sach
van cac » van hac, van cau, van bac
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
v nang » va nang, vu nang, van nang
nang o » nang co, nang ho, nang ro
vi cua » vai cua, di cua
o hoi » co hoi, o hoc, o hai

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: ((su sach) OR (so sach)) v nang o hoi. hieu van cac thuc va hanh vi cua tre~.
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (so sach)) v nang o hoi. hieu van cac thuc va hanh vi cua tre*.