Perhaps you should try some spelling variations:
cam thuc » nam thuc, cam thu, can thuc
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
hanh di » hanh vi, hanh de, hang di
di cua » dai cua, doi cua, de cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu cac ky ((nang xa) OR (nang ma)) hoi. hieu ve ((cam thuc) or (am thuc)) va hanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu cac ky ((nang xa) OR (nang ma)) hoi. hieu ve ((cam thuc) OR (am thuc)) va hanh di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu cac ky ((nang xa) OR (nang ma)) hoi. hieu ve ((cam thuc) or (am thuc)) va hanh di cua te".
• Adding a wildcard symbol may retrieve word variants: tu cac ky ((nang xa) OR (nang ma)) hoi. hieu ve ((cam thuc) or (am thuc)) va hanh di cua te*.