Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
hai cua » thai cua, dai cua, hoi cua
vai cua » dai cua, lai cua, bai cua
va danh » va dinh, va dan, va hanh
thuc va » thuc vat, thuc dan, thuc day
so sach » so sanh, bo sach, co sach
lai hoi » dai hoi, lai hoa, lai roi
mai doi » moi doi, mai hoi, mai khoi
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
sach v » sach va, sach y, sach 2
v nang » va nang, vu nang, van 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 ((mai doi) or (lai hoi)). hieu ve cam thuc va danh ((vai cua) OR (hai cua)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach v nang ((mai doi) OR (lai hoi)). hieu ve cam thuc va danh ((vai cua) OR (hai cua)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach v nang ((mai doi) or (lai hoi)). hieu ve cam thuc va danh ((vai cua) OR (hai cua)) viet".
• Adding a wildcard symbol may retrieve word variants: so sach v nang ((mai doi) or (lai hoi)). hieu ve cam thuc va danh ((vai cua) OR (hai cua)) viet*.