Perhaps you should try some spelling variations:
dang dinh » dang sinh, dang dieu, dang hanh
dan dinh » doan dinh, van dinh, dao dinh
cam thuc » am thuc, nam thuc, can thuc
su sach » so sach, vu sach
tang ma » mang may, tang van
hieu ve » hieu va, hieu van
cam thu » nam thu, cac thu, ca thu
cua te » cua tu
y tang » ky tang, 6 tang, 7 tang
ma hoi » mai hoi, xa hoi, ma hoa

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 y tang ma hoi. hieu ve ((cam thuc) OR (cam thu)) ((dan dinh) or (dang dinh)) dai cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y tang ma hoi. hieu ve ((cam thuc) OR (cam thu)) ((dan dinh) OR (dang dinh)) dai cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y tang ma hoi. hieu ve ((cam thuc) OR (cam thu)) ((dan dinh) or (dang dinh)) dai cua te".
• Adding a wildcard symbol may retrieve word variants: su sach y tang ma hoi. hieu ve ((cam thuc) OR (cam thu)) ((dan dinh) or (dang dinh)) dai cua te*.