Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
nang mai » nang ma, nang tai, nang cai
lang mai » lang dai, lang hai, lang man
sach van » sach han, sach va, bach van
vai cua » dai cua, hai cua, lai 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
hieu ve » hieu va, hieu van
ve cam » ve cham, ve cac, va cam
vi cua » di cua

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