Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thanh va » thanh van, hanh va, thanh ha
dang xay » dang van, van xay
hieu van » hieu va, thien van, lieu va
tu sach » thu sach, su sach, te sach
cua tre » cua te, cua triet, dua tren
sach ky » sac ky, sach y, sach ty
van cac » van hac, van cau, van bac
lang ha » long ha
cuu tre » cau tren, cau treo
cac lo » cac lop, cac co, cac bo
lo ban » co ban, lo van, ly ban

You may be able to get more results by adjusting your search query.

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