Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
van hanh » van thanh, ban hanh, van anh
ty hang » ly hang, thi hang, thu hang
hieu va » lieu va, hieu qua
cam luc » cam xuc, cau luc
luc van » luoc van, luu van, duc van
cua tre » cua te, cuu tre, cua triet
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 ((ty hang) or (ty xang)) xa hoi. ((hieu van) or (hieu va)) cam luc van hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ((ty hang) OR (ty xang)) xa hoi. ((hieu van) OR (hieu va)) cam luc van hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ((ty hang) or (ty xang)) xa hoi. ((hieu van) or (hieu va)) cam luc van hanh vi cua tre*.