Perhaps you should try some spelling variations:
va triet » va thiet, va trien, ve triet
hanh mai » hanh ma, hanh mau, hanh may
ban hanh » ban hang
cac tuc » cac tu, cac tac, cac nuoc
cac toc » cac toi, cac nuoc, cac thoi
tu sach » thu sach, su sach, te sach
hieu ve » hieu va, hieu van
ky danh » ky anh
ky dang » ky nang

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 dang) or (ky danh)) xa hoi. hieu ve ((cac tuc) OR (cac toc)) ban hanh mai va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ky dang) OR (ky danh)) xa hoi. hieu ve ((cac tuc) OR (cac toc)) ban hanh mai va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ky dang) or (ky danh)) xa hoi. hieu ve ((cac tuc) OR (cac toc)) ban hanh mai va triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ky dang) or (ky danh)) xa hoi. hieu ve ((cac tuc) OR (cac toc)) ban hanh mai va triet*.