Perhaps you should try some spelling variations:
cac thuc » cach thuc, cac thu, can thuc
so sach » so sanh, bo sach, co sach
tang ma » mang may, tang van
thuc va » thuc vat, thuc dan, thuc day
va dinh » van dinh, va kinh, va tinh
dinh di » dinh du, dinh vi, danh di
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo

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