Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
sinh dai » sinh thai, si dai, sinh vat
dinh dat » dinh ket, dinh van, dinh lam
thuc dan » thuc hanh, hoc dan, thuc vat
dan thuc » dan toc, am thuc
van dan » van ban, ban dan, van dao
sach ky » sach y, sach ty, sach kem
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet
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: thu ((sach ky) or (sac ky)) lang xa hoi. hieu van dan thuc dan ((dinh dat) or (sinh dai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sac ky)) lang xa hoi. hieu van dan thuc dan ((dinh dat) OR (sinh dai)) cua tre.
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sac ky)) lang xa hoi. hieu van dan thuc dan ((dinh dat) or (sinh dai)) cua tre*.