Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
so sach » so sanh, bo sach, co sach
mang xa » lang xa, mang may, dang xay
nang ma » tang ma, sang ma, nang cao
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
doi cua » dai cua, hoi cua
di cua » dai cua, de cua, do cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach y ((mang xa) or (nang ma)) hoi. lieu va cac thuc va danh ((di cua) OR (doi cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y ((mang xa) OR (nang ma)) hoi. lieu va cac thuc va danh ((di cua) OR (doi cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y ((mang xa) or (nang ma)) hoi. lieu va cac thuc va danh ((di cua) OR (doi cua)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach y ((mang xa) or (nang ma)) hoi. lieu va cac thuc va danh ((di cua) OR (doi cua)) tre*.