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