Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
cac xuc » cam xuc, cac nuoc, chat xuc
dai cuu » dai cua, dai huu
va hanh » va thanh, va danh, ban hanh
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va
y xang » ty xang
xang o » lang o, tang o, dang o
o hoc » co hoc, mo hoc, so hoc

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 xang o hoc. ((hieu va) OR (hieu qua)) cac xuc ((va hanh) or (van hanh)) dai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y xang o hoc. ((hieu va) OR (hieu qua)) cac xuc ((va hanh) OR (van hanh)) dai cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y xang o hoc. ((hieu va) OR (hieu qua)) cac xuc ((va hanh) or (van hanh)) dai cuu tre*".