Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
tra nang » thi nang, kha nang, da nang
cuc ban » cua ban, cac ban, cuu ban
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma
cua tre » cua te, cuu tre, cua triet
va cam » va cham, va cac, va cao
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: ((te sach) or (toc sach)) tra nang xa hoi. hieu va cam ((cuc ban) or (cuu van)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) tra nang xa hoi. hieu va cam ((cuc ban) OR (cuu van)) hanh vi cua tre.
• Adding a wildcard symbol may retrieve word variants: ((te sach) or (toc sach)) tra nang xa hoi. hieu va cam ((cuc ban) or (cuu van)) hanh vi cua tre*.