Perhaps you should try some spelling variations:
soziale conditions » sale conditions, smale conditions, mobile conditions
21 united » 11 united, 2 united, 20 united
1 united » 11 united, 1 unified, 1 units
21 21st » 11 21st, 2 21st, 20 21st
1 21st » _ 21st, a 21st

Try widening your search to All Fields.

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: %22teenagers %((21 united) OR (1 united)) states %auf soziale conditions %((21 21st) OR (1 21st)) century%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22teenagers %((21 united) OR (1 united)) states %auf soziale conditions %((21 21st) or (1 21st)) century%22".
• Adding a wildcard symbol may retrieve word variants: %22teenagers %((21 united) OR (1 united)) states %auf soziale conditions %((21 21st) or (1 21st)) century%22*.