Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
dieu ban » dieu can, dien ban, dieu hanh
van hanh » van thanh, ban hanh, van anh
hang luc » nang luc, hang luan, hang truc
hieu ban » hieu van, lieu ban, hieu bai
va hanh » va thanh, va danh, ban hanh
nang ma » tang ma, sang ma, nang cao
hai cua » thai cua, dai cua, hoi cua
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach y nang ma hoi. ((hieu ban) OR (dieu ban)) hang luc ((va hanh) or (van hanh)) hai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ma hoi. ((hieu ban) OR (dieu ban)) hang luc ((va hanh) OR (van hanh)) hai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang ma hoi. ((hieu ban) OR (dieu ban)) hang luc ((va hanh) or (van hanh)) hai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ma hoi. ((hieu ban) OR (dieu ban)) hang luc ((va hanh) or (van hanh)) hai cua tre*.