Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
ban hanh » ban hang
sach ky » sac ky, sach y, sach ty
va danh » va dinh, va dan, va hanh
cua tre » cua te, cuu tre, cua triet
dang ha » dong ha, dung ha, lang ha
ky dang » ky nang, ky danh
va cao » va cac, va co, va dao
va cam » va cham, va cac, va cai
ha hoi » hoa hoi, ha noi, xa hoi
vi cua » vai cua, di cua

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 dang ha hoi. hieu ((va cam) OR (va cao)) xuc ((ban hanh) or (va danh)) vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang ha hoi. hieu ((va cam) OR (va cao)) xuc ((ban hanh) OR (va danh)) vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang ha hoi. hieu ((va cam) OR (va cao)) xuc ((ban hanh) or (va danh)) vi cua tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang ha hoi. hieu ((va cam) OR (va cao)) xuc ((ban hanh) or (va danh)) vi cua tre*.