Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
nam thuc » nam thuoc, am thuc, nam thu
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
hieu le » hieu ve, hieu he, hieu ly
ky dang » ky nang, ky danh
me hoi » le hoi
va cao » va cac, va co, va dao
le nam » ly nam, he nam, le na
va ca » va cac, va cai, va cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky dang ((me hoi) or (ma hoa)). hieu le nam thuc van hanh ((va ca) OR (va cao)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky dang ((me hoi) OR (ma hoa)). hieu le nam thuc van hanh ((va ca) OR (va cao)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky dang ((me hoi) or (ma hoa)). hieu le nam thuc van hanh ((va ca) OR (va cao)) viet".
• Adding a wildcard symbol may retrieve word variants: su sach ky dang ((me hoi) or (ma hoa)). hieu le nam thuc van hanh ((va ca) OR (va cao)) viet*.