Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cao thuc » cao thuoc, bao thuc, can thuc
van hanh » van thanh, ban hanh, van anh
va hanh » va thanh, va danh, ban hanh
vai cuu » vai cua
cuu tre » cua tre, cau tren, cau treo
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, me hoi
va cao » va cac, va co, va dao

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) or (ma hoa)). lieu va cao thuc ((va hanh) OR (van hanh)) vai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach y nang ((ma hoi) OR (ma hoa)). lieu va cao thuc ((va hanh) OR (van hanh)) vai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach y nang ((ma hoi) or (ma hoa)). lieu va cao thuc ((va hanh) OR (van hanh)) vai cuu tre".
• Adding a wildcard symbol may retrieve word variants: toc sach y nang ((ma hoi) or (ma hoa)). lieu va cao thuc ((va hanh) OR (van hanh)) vai cuu tre*.