Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
mai khoi » mai khoa, tai khoa, cac khoi
vai cua » hai cua, lai cua, bai cua
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
so sach » so sanh, bo sach, co sach
vu nang » vuc nang, va nang, vu dang
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
v nang » va nang, van nang, voi nang

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 ((v nang) OR (vu nang)) mai khoi. hieu ve cam thuc va hanh ((vai cua) or (dai cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ((v nang) OR (vu nang)) mai khoi. hieu ve cam thuc va hanh ((vai cua) OR (dai cua)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ((v nang) OR (vu nang)) mai khoi. hieu ve cam thuc va hanh ((vai cua) or (dai cua)) viet".
• Adding a wildcard symbol may retrieve word variants: so sach ((v nang) OR (vu nang)) mai khoi. hieu ve cam thuc va hanh ((vai cua) or (dai cua)) viet*.