Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
nang mai » nang ma, nang tai, lang mai
cam thuc » am thuc, nam thuc, cam thu
va danh » va dinh, va dan, dia danh
va hanh » van hanh, va thanh, ban hanh
so sach » so sanh, co sach, hoc sach
hieu ve » hieu va, hieu van
mai hoi » mai khoi, dai hoi, lai hoi
va nang » van nang, da nang, cam nang
bo sach » co sach, hoc sach
vi cua » vai cua, di cua
ve cam » ve cham, ve cac, va cam

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