Perhaps you should try some spelling variations:
so triet » su triet, so thiet, bo triet
hieu van » hieu va, thien van, lieu va
danh sai » dung sai, danh bat, danh dau
danh dai » danh dau, danh di, vanh dai
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang x hoi. ((hieu ve) or (hieu van)) am thuc va ((danh dai) OR (danh sai)) so triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang x hoi. ((hieu ve) OR (hieu van)) am thuc va ((danh dai) OR (danh sai)) so triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang x hoi. ((hieu ve) or (hieu van)) am thuc va ((danh dai) OR (danh sai)) so triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang x hoi. ((hieu ve) or (hieu van)) am thuc va ((danh dai) OR (danh sai)) so triet*.