Perhaps you should try some spelling variations:
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
hanh vii » hanh voi, hanh va, hanh noi
lang xa » lang ha, dang xay, lang van
van cau » van dau, van hau, van chat
cau dia » cac dia, cuu dia, cau giay
cua tre » cua te, cuu tre, cua triet
y lang » o lang, _ lang, tay lang

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)) y lang xa hoi. hieu van cau dia ban ((hanh vii) or (hanh vi)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((te sach) OR (toc sach)) y lang xa hoi. hieu van cau dia ban ((hanh vii) OR (hanh vi)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((te sach) OR (toc sach)) y lang xa hoi. hieu van cau dia ban ((hanh vii) or (hanh vi)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((te sach) OR (toc sach)) y lang xa hoi. hieu van cau dia ban ((hanh vii) or (hanh vi)) cua tre*.