Perhaps you should try some spelling variations:
cam thuc » nam thuc, cam thu, can thuc
thanh va » thanh van, hanh va, thanh ve
thanh ha » thanh hoa, thanh hai, nhanh ha
va triet » va thiet, va trien, ve triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van

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 ky nang xa hoi. hieu ve ((cam thuc) or (am thuc)) ban ((thanh va) OR (thanh ha)) va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang xa hoi. hieu ve ((cam thuc) OR (am thuc)) ban ((thanh va) OR (thanh ha)) va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang xa hoi. hieu ve ((cam thuc) or (am thuc)) ban ((thanh va) OR (thanh ha)) va triet".
• Adding a wildcard symbol may retrieve word variants: su sach ky nang xa hoi. hieu ve ((cam thuc) or (am thuc)) ban ((thanh va) OR (thanh ha)) va triet*.