Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu cao » chieu cao, hieu cac, hieu ca
sach ky » sac ky, sach y, sach ty
luc van » luoc van, duc van, luc va
luu van » cuu van, luan van, luu hanh
hanh ve » hanh vi, hanh va
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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 x hoi. hieu cao chat ((luc van) or (luu van)) ((hanh ve) or (hanh kem)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang x hoi. hieu cao chat ((luc van) OR (luu van)) ((hanh ve) OR (hanh kem)) cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang x hoi. hieu cao chat ((luc van) or (luu van)) ((hanh ve) or (hanh kem)) cua tre*.