Perhaps you should try some spelling variations:
nham thuc » nhan thuc, nam thuc, nham thu
toc sach » hoc sach, doc sach, thuoc sach
hieu van » hieu va, thien van, lieu va
van nham » van nam, van nhan, van tham
thuc dan » thuc hanh, hoc dan, thuc vat
sach ty » sach y, sach tu, sach thu
ty sang » ty xang, ty hang, duy sang
sang ma » tang ma, nang ma, sang tao
dinh vi » dinh ve, dinh viet, dinh tri
cuu tre » cua tre, cau tren, cau treo
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ty sang ma hoi. hieu van nham thuc dan ((dinh vi) or (chinh tri)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ty sang ma hoi. hieu van nham thuc dan ((dinh vi) OR (chinh tri)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: toc sach ty sang ma hoi. hieu van nham thuc dan ((dinh vi) or (chinh tri)) cuu tre*.