Perhaps you should try some spelling variations:
sach tru » sach truc, sach thu, sach tu
hieu van » hieu va, thien van, lieu va
cuu ban » cuu van, cua ban, cuu san
cuc ban » cua ban, cac ban, duc ban
van cam » van nam, van lam, van cau
nang xa » nang x, lang xa, nang ma
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: tu ((sach tru) or (sach thieu)) nang xa hoi. hieu van cam ((cuc ban) OR (cuu ban)) hanh vi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach tru) OR (sach thieu)) nang xa hoi. hieu van cam ((cuc ban) OR (cuu ban)) hanh vi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach tru) or (sach thieu)) nang xa hoi. hieu van cam ((cuc ban) OR (cuu ban)) hanh vi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((sach tru) or (sach thieu)) nang xa hoi. hieu van cam ((cuc ban) OR (cuu ban)) hanh vi cua tre*.