Perhaps you should try some spelling variations:
van thanh » ban thanh, van tuan
hai thuc » thai thuc, dai thuc, ha thuc
thanh va » thanh van, hanh va, thanh ha
hieu van » thien van, lieu va, hieu ve
thuc van » thuc vat, thuc dan, thuc va
cua tre » cua te, cuu tre, cua triet
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
va cua » va chua, via cua, ca cua
su sac » su sach, su cac, su xac
sac ky » cac ky, sai ky

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sac ky ((nang xa) or (nang ma)) hoi. ((hieu van) or (hieu va)) hai thuc van thanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sac ky ((nang xa) OR (nang ma)) hoi. ((hieu van) OR (hieu va)) hai thuc van thanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: su sac ky ((nang xa) or (nang ma)) hoi. ((hieu van) or (hieu va)) hai thuc van thanh va cua tre*.