Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
vat hanh » vat thanh, van hanh, va hanh
cua viet » ca viet, hoa viet, cua dieu
so sanh » do sanh
sang ma » tang ma, nang ma, sang tao
hieu ve » hieu van
hieu va » lieu va, hieu qua
sanh y » sinh y, anh y, hanh y
y sang » _ sang, duy sang
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sanh y sang ma hoi. ((hieu ve) or (hieu va)) cam thuc vat hanh vi ((cua viet) OR (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sanh y sang ma hoi. ((hieu ve) OR (hieu va)) cam thuc vat hanh vi ((cua viet) OR (cua vat)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sanh y sang ma hoi. ((hieu ve) or (hieu va)) cam thuc vat hanh vi ((cua viet) OR (cua vat))".
• Adding a wildcard symbol may retrieve word variants: so sanh y sang ma hoi. ((hieu ve) or (hieu va)) cam thuc vat hanh vi ((cua viet) OR (cua vat))*.