Perhaps you should try some spelling variations:
cau thuc » cau truc, cuu thuc, can thuc
hieu van » thien van, lieu va, hieu ve
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cua triet, dua tren
tinh di » tinh doi, trinh di, tinh da
va tinh » may tinh
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
sang ma » tang ma, nang ma, sang tao
cuu tre » cau tren, cau treo
y sang » _ sang, duy sang

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 y sang ma hoa. ((hieu van) or (hieu va)) cau thuc va tinh di ((cua tre) OR (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y sang ma hoa. ((hieu van) OR (hieu va)) cau thuc va tinh di ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y sang ma hoa. ((hieu van) or (hieu va)) cau thuc va tinh di ((cua tre) OR (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: tu sach y sang ma hoa. ((hieu van) or (hieu va)) cau thuc va tinh di ((cua tre) OR (cuu tre))*.