Perhaps you should try some spelling variations:
hieu van » thien van, lieu va, hieu ve
cac thuc » cach thuc, cac thu, can thuc
thuc day » thuc dan, thuc vat
day dinh » dao dinh, day danh, dang dinh
dinh dai » dinh dat, sinh dai, dinh dao
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet

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

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