Perhaps you should try some spelling variations:
bo sach » co sach, hoc sach
ky mang » ky nang, ke mang, ky tang
ky dang » ky nang, ky danh
mai hoi » mai khoi, dai hoi, lai hoi
thuc va » thuc vat, thuc dan, thuc day
va hanh » van hanh, va thanh, va danh
he nam » nghe nam
vi hoa » voi hoa, vi hoc, va hoa

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

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