Perhaps you should try some spelling variations:
lang van » dang van, tang van, hoang van
dang xay » dang van, van xay
lam thuc » lam thuoc, am thuc, nam thuc
thuc van » thuc vat, thuc dan, thuc va
van hanh » van thanh, ban hanh, van anh
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
hanh di » hanh vi, hanh de, hang di
cau tre » cau tren, cau treo, cau tra
va lam » van lam, va lap
di cau » da cau, diem cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky ((lang van) or (dang xay)) hoi. hieu va lam thuc van hanh di cau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((lang van) OR (dang xay)) hoi. hieu va lam thuc van hanh di cau tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky ((lang van) or (dang xay)) hoi. hieu va lam thuc van hanh di cau tre*.