Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hanh de » hanh ve
cam luc » cam xuc, cau luc
sach vu » sach va, sach tu, sach uu
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
luc va » duc va, tuc va, loc va

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