Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
cac tuc » cac toc, cac tu, cac tac
va hanh » va thanh, va danh, ban hanh
cua tre » cua te, cuu tre, cua triet
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van nang
ca cua » co cua

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: tu sach v nang ((le hoi) OR (ma hoa)). hieu va cac tuc ((va hanh) OR (van hanh)) ca cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach v nang ((le hoi) or (ma hoa)). hieu va cac tuc ((va hanh) OR (van hanh)) ca cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach v nang ((le hoi) or (ma hoa)). hieu va cac tuc ((va hanh) OR (van hanh)) ca cua tre*.