Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tham duc » pham duc, tham du, than duc
sach ky » sac ky, sach y, sach ty
van hoi » van hoa, van hoc, van loi
van hoe » van hoa, van hoc, van hieu
hieu va » lieu va, hieu qua
va tham » van tham, va cham, va thanh
hanh de » hanh ve
cua tre » cua te, cuu tre, cua triet

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 ((van hoi) or (van hoe)). hieu va tham duc va ((hanh de) OR (hanh kem)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang ((van hoi) OR (van hoe)). hieu va tham duc va ((hanh de) OR (hanh kem)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang ((van hoi) or (van hoe)). hieu va tham duc va ((hanh de) OR (hanh kem)) cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang ((van hoi) or (van hoe)). hieu va tham duc va ((hanh de) OR (hanh kem)) cua tre*.