Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
hieu van » hieu va, thien van, lieu va
thanh va » thanh van, hanh va, thanh ha
dang xay » dang van, van xay
sach ky » sac ky, sach y, sach ty
tu sach » thu sach, su sach, te sach
lang ha » long ha
cua tre » cua te, cuu tre, cua triet
cac lo » cac lop, cac bo, cac ho
cac co » cac cong
va cua » va chua, via cua, ca cua

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) OR (cac co)) ban thanh va cua 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) OR (cac co)) ban thanh va cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((lang ha) or (dang xay)) hoi. hieu van ((cac lo) OR (cac co)) ban thanh va cua tre*.