Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
sach ky » sac ky, sach y, sach ty
van cau » van dau, van hau, van chat
va danh » va dan, va hanh, dia danh
va dinh » van dinh, va kinh, va tinh
cua tre » cua te, cuu tre, cua triet
va cau » va cac, va dau, va cao
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 ky nang x hoi. hieu ((va cau) or (van cau)) trung ((va danh) OR (va dinh)) dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang x hoi. hieu ((va cau) OR (van cau)) trung ((va danh) OR (va dinh)) dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang x hoi. hieu ((va cau) or (van cau)) trung ((va danh) OR (va dinh)) dai cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang x hoi. hieu ((va cau) or (van cau)) trung ((va danh) OR (va dinh)) dai cua tre*.