Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va hanh » van hanh, va thanh, va danh
cau duc » cao duc, cau luc, chu duc
hieu va » lieu va, hieu qua
sach ly » sach y, sach lo, sach ty
hieu ve » hieu van
ly nang » ky nang, ly hang, ly vang
cua tre » cua te, cuu tre, cua triet
vi cua » vai cua, di cua
o hoi » co hoi, o hoc, o hai
x hoi » xa hoi, x ho, 5 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: thu sach ly nang ((x hoi) OR (o hoi)). ((hieu ve) OR (hieu va)) cau duc va hanh vi cua tre~.
• Adding a wildcard symbol may retrieve word variants: thu sach ly nang ((x hoi) or (o hoi)). ((hieu ve) or (hieu va)) cau duc va hanh vi cua tre*.