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
cam tuc » cam xuc, cam tu, nam thuc
hieu va » lieu va
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
cua tre » cua te, cuu tre, cua triet
tuc va » thuc va, truc va, tuc xa

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