Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
cac thuc » cach thuc, cac thu, can thuc
va hanh » va thanh, va danh, ban hanh
van cac » van hac, van cau, van bac
su sach » vu sach
so sach » so sanh, bo sach, co sach
cua tre » cua te, cuu tre, cua triet
nang o » nang co, nang ho, nang ro
v nang » va nang, vu nang, van nang
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) OR (van hanh)) vi cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (so sach)) v nang o hoi. hieu van cac thuc ((va hanh) OR (van 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) OR (van hanh)) vi cua tre*.