Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cau thuc » cau truc, can thuc, cau phuc
cuu thuc » cuu tac
ban hang » ngan hang
so sach » so sanh, bo sach, co sach
may hoi » may thoi, tay hoi, mai hoi
cua tre » cua te, cuu tre, cua triet
y mang » cay mang

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 y mang may hoi. hieu van ((cau thuc) OR (cuu thuc)) ban hang va ((cua tre) or (cua vat))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach y mang may hoi. hieu van ((cau thuc) OR (cuu thuc)) ban hang va ((cua tre) OR (cua vat)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach y mang may hoi. hieu van ((cau thuc) OR (cuu thuc)) ban hang va ((cua tre) or (cua vat))".
• Adding a wildcard symbol may retrieve word variants: so sach y mang may hoi. hieu van ((cau thuc) OR (cuu thuc)) ban hang va ((cua tre) or (cua vat))*.