Perhaps you should try some spelling variations:
thanh dai » thanh tai, thanh dat, thanh oai
thanh hai » thanh phan, thanh hoa, thanh san
van nang » van quang, van dong, van dung
tu sach » thu sach, su sach, te sach
cac cac » cac cach, ca cac, cac bac
cac van » cac dan
cua tre » cua te, cuu tre, cua triet
o hoi » co hoi, o hoc, o hai

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 ((van nang) or (van ban)) o hoi. lieu va cac cac van ((thanh dai) OR (thanh hai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((van nang) OR (van ban)) o hoi. lieu va cac cac van ((thanh dai) OR (thanh hai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((van nang) or (van ban)) o hoi. lieu va cac cac van ((thanh dai) OR (thanh hai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((van nang) or (van ban)) o hoi. lieu va cac cac van ((thanh dai) OR (thanh hai)) cua tre*.