Perhaps you should try some spelling variations:
ban thanh » ban hanh, ban hang
thien van » thi van
thanh ca » thanh cha, thanh cac, thanh ha
thuc ban » thuoc ban, thuc dan, thu ban
nam thuc » nam thuoc, am thuc, nam thu
cua tre » cua te, cuu tre, cua triet
sach ky » sach y, sach ty, sach kem
nang xa » lang xa, nang ma, mang xa
sac ky » cac ky, sai ky
ca cua » co cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so ((sach ky) OR (sac ky)) ((nang xa) or (nang x)) hoi. thien van nam thuc ban thanh ca cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so ((sach ky) OR (sac ky)) ((nang xa) OR (nang x)) hoi. thien van nam thuc ban thanh ca cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so ((sach ky) OR (sac ky)) ((nang xa) or (nang x)) hoi. thien van nam thuc ban thanh ca cua tre".
• Adding a wildcard symbol may retrieve word variants: so ((sach ky) OR (sac ky)) ((nang xa) or (nang x)) hoi. thien van nam thuc ban thanh ca cua tre*.