Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thien van » thi van
hieu van » hieu va, lieu va, hieu ve
thanh va » thanh van, hanh va, thanh ha
dang xay » dang van, van xay
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, lang van
cua tre » cua te, cuu tre, cua triet
cac lo » cac lop, cac co, cac bo
lo ban » co ban, lo van, ly ban
va cua » va chua, via cua, ca 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 ky ((lang xa) or (dang xay)) hoi. ((hieu van) OR (thien van)) cac lo ban thanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((lang xa) OR (dang xay)) hoi. ((hieu van) OR (thien van)) cac lo ban thanh va cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((lang xa) or (dang xay)) hoi. ((hieu van) OR (thien van)) cac lo ban thanh va cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((lang xa) or (dang xay)) hoi. ((hieu van) OR (thien van)) cac lo ban thanh va cua tre*.