Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van
hieu va » lieu va, hieu qua
sach ky » sac ky, sach y, sach ty
thuc va » thuc vat, thuc dan, thuc day
vai cua » dai cua, hai cua, lai cua
hoi cua » hoi chuc
va dan » ca dan, va dao, va dau
va nam » van nam, ha nam, va nay

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 ky ((dang xay) OR (van xay)) hoi. hieu va nam thuc va dan ((vai cua) or (hoi cua)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky ((dang xay) OR (van xay)) hoi. hieu va nam thuc va dan ((vai cua) OR (hoi cua)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky ((dang xay) OR (van xay)) hoi. hieu va nam thuc va dan ((vai cua) or (hoi cua)) triet".
• Adding a wildcard symbol may retrieve word variants: toc sach ky ((dang xay) OR (van xay)) hoi. hieu va nam thuc va dan ((vai cua) or (hoi cua)) triet*.