Perhaps you should try some spelling variations:
va trien » va truyen, va thiet, va tuyen
cau thuc » cau truc, cuu thuc, can thuc
va triet » va thiet, ve triet, cua triet
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
hieu ve » hieu van
nang ma » tang ma, sang ma, nang cao
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ma hoi. ((hieu ve) OR (hieu va)) cau thuc va hanh vi ((va triet) OR (va trien))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ma hoi. ((hieu ve) or (hieu va)) cau thuc va hanh vi ((va triet) OR (va trien))~".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ma hoi. ((hieu ve) or (hieu va)) cau thuc va hanh vi ((va triet) OR (va trien))*.