Perhaps you should try some spelling variations:
sach tham » sach nha
toc sach » hoc sach, doc sach, thuoc sach
hanh vai » hanh vi, hanh va, hanh tai
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
va cao » va cac, va co, va dao
luc va » duc va, tuc va, loc va
va cam » va cham, va cac, va cai

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