Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hang dai » hoang dai, hang tai, hang dau
van hang » van khang, van hoang, van thang
cam thuc » am thuc, nam thuc, can thuc
sach ky » sac ky, sach y, sach ty
cam thu » nam thu, cac thu, ca thu
co sach » bo sach, cuon sach, hoc sach
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
dai va » mai va

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

• Performing a fuzzy search may retrieve terms with similar spellings: co sach ky ((nang xa) OR (nang ma)) hoi. hieu va ((cam thuc) or (cam thu)) van hang dai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: co sach ky ((nang xa) OR (nang ma)) hoi. hieu va ((cam thuc) OR (cam thu)) van hang dai va triet*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "co sach ky ((nang xa) OR (nang ma)) hoi. hieu va ((cam thuc) or (cam thu)) van hang dai va triet*".