Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
cau treo » cau theo, cau tren, cau triet
sach thu » sach thue, sach thieu, sach tham
lang xa » lang ha, dang xay, lang van
hieu va » hieu qua
sach ty » sach y, sach tu, xach tay
thuc va » thuc vat, thuc dan, thuc day
va dau » va dao
dau va » dau ve, lau va
va cau » van cau, va cac, va cao

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) OR (sach thu)) lang xa hoi. ((hieu va) or (lieu va)) nam thuc va dau va cau treo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc ((sach ty) OR (sach thu)) lang xa hoi. ((hieu va) OR (lieu va)) nam thuc va dau va cau treo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc ((sach ty) OR (sach thu)) lang xa hoi. ((hieu va) or (lieu va)) nam thuc va dau va cau treo".
• Adding a wildcard symbol may retrieve word variants: toc ((sach ty) OR (sach thu)) lang xa hoi. ((hieu va) or (lieu va)) nam thuc va dau va cau treo*.