Perhaps you should try some spelling variations:
va triet » va trien, ve triet, cua triet
su sach » so sach, vu sach
hanh va » hang va, hanh vi
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
hieu ve » hieu va, hieu van
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, ma hoa, me hoi
ve am » va am
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 ty nang ((ma hoi) OR (xa hoi)). hieu ve am thuc va hanh va ((va triet) or (va thiet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ty nang ((ma hoi) OR (xa hoi)). hieu ve am thuc va hanh va ((va triet) OR (va thiet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ty nang ((ma hoi) OR (xa hoi)). hieu ve am thuc va hanh va ((va triet) or (va thiet))".
• Adding a wildcard symbol may retrieve word variants: su sach ty nang ((ma hoi) OR (xa hoi)). hieu ve am thuc va hanh va ((va triet) or (va thiet))*.