Perhaps you should try some spelling variations:
thuat sac » thuat sach, thuat san, thuat tac
sieu viet » su viet, dien viet, viet viet
bien viet » dien viet, tieng viet, trien viet
van thanh » ban thanh, van tuan
thanh via » thanh va, thanh vien, thanh vinh
va triet » va thiet, va trien, ve triet
sac ky » cac ky, sai ky
cac vo » cac co, cac vi, cac bo
via va » via van, vua va, gia va

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sac ky nang ((xa hoi) or (x ho)). ((sieu viet) OR (bien viet)) cac vo van thanh via va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sac ky nang ((xa hoi) OR (x ho)). ((sieu viet) OR (bien viet)) cac vo van thanh via va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sac ky nang ((xa hoi) or (x ho)). ((sieu viet) OR (bien viet)) cac vo van thanh via va triet".
• Adding a wildcard symbol may retrieve word variants: thuat sac ky nang ((xa hoi) or (x ho)). ((sieu viet) OR (bien viet)) cac vo van thanh via va triet*.