Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
cac duc » cac du, cao duc, cac dac
dai cuu » dai cua, dai huu
va danh » va dinh, va dan, va hanh
va vanh » va van, va hanh, va anh
sach ty » sach y, sach tu, sach thu
hieu va » lieu va
ty nang » ky nang, ty xang, ty hang
cuu tre » cua tre, cau tren, cau treo
x hoi » xa hoi, o hoi, x ho

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 ty nang x hoi. ((hieu va) or (hieu qua)) cac duc ((va vanh) OR (va danh)) dai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty nang x hoi. ((hieu va) OR (hieu qua)) cac duc ((va vanh) OR (va danh)) dai cuu tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ty nang x hoi. ((hieu va) or (hieu qua)) cac duc ((va vanh) OR (va danh)) dai cuu tre*".