Perhaps you should try some spelling variations:
thao khoa » thai khoa, toan khoa, pham khoa
tao khoi » tao hoi, lao khoa, tao boi
cam thuc » am thuc, nam thuc, cam thu
te sach » toc sach
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
danh vi » hanh vi, dinh vi, danh di
y sang » _ sang, duy sang
vi cua » vai cua, di cua

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

• If you are trying to use Boolean operators, they must be ALL CAPS: te sach y sang ((tao khoi) OR (thao khoa)). ((hieu ve) OR (hieu qua)) cam thuc va danh vi cua vat~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach y sang ((tao khoi) OR (thao khoa)). ((hieu ve) or (hieu qua)) cam thuc va danh vi cua vat~".
• Adding a wildcard symbol may retrieve word variants: te sach y sang ((tao khoi) OR (thao khoa)). ((hieu ve) or (hieu qua)) cam thuc va danh vi cua vat*.