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
cua tre » cua te, cuu tre, cua triet
cac lop » cac hop, cac loai
lang xa » lang ha, lang van
sac ky » cac ky, sai ky
cac lo » cac co, cac bo, cac ho
va cua » va chua, via cua, ca cua
tu sac » tu sach, tu cac, tu san

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 sac ky ((lang xa) OR (dang xay)) hoi. hieu van ((cac lo) OR (cac lop)) ban thanh va cua tre~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sac ky ((lang xa) or (dang xay)) hoi. hieu van ((cac lo) OR (cac lop)) ban thanh va cua tre~".
• Adding a wildcard symbol may retrieve word variants: tu sac ky ((lang xa) or (dang xay)) hoi. hieu van ((cac lo) OR (cac lop)) ban thanh va cua tre*.