Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh tai » thanh tai, hang tai, han tai
dam thuc » am thuc, dan thuc, nam thuc
va hanh » van hanh, va thanh, va danh
sach ky » sac ky, sach y, sach ty
su sach » so sach, vu sach
ky sang » ky nang, ky dang, ky tang
hieu va » lieu va, hieu qua
ma hoi » mai hoi, ma hoa, me hoi
tai va » thai va, mai va, tri va

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: su sach ky sang ((ma hoi) OR (xa hoi)). hieu va ((dam thuc) OR (cam xuc)) va hanh tai va triet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky sang ((ma hoi) OR (xa hoi)). hieu va ((dam thuc) or (cam xuc)) va hanh tai va triet~".
• Adding a wildcard symbol may retrieve word variants: su sach ky sang ((ma hoi) OR (xa hoi)). hieu va ((dam thuc) or (cam xuc)) va hanh tai va triet*.