Perhaps you should try some spelling variations:
dam thuc » am thuc, dan thuc, nam thuc
va triet » va trien, ve triet, cua triet
su sach » so sach, vu sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
va dung » van dung, va duong, vat dung
ma hoi » mai hoi, xa hoi, ma hoa
thiet » thieu

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 ma hoi. hieu va ((dam thuc) or (cam xuc)) va dung tai ((va triet) OR (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky nang ma hoi. hieu va ((dam thuc) OR (cam xuc)) va dung tai ((va triet) OR (va thiet))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky nang ma hoi. hieu va ((dam thuc) or (cam xuc)) va dung tai ((va triet) OR (va thiet))*".