Perhaps you should try some spelling variations:
kernmigration » kettenmigration, emigration, weltmigration
climigration » crimmigration, weltmigration, antimigration
klimamigration » immigration, crimmigration
remigration » emigration, migration, immigration

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: (((kernmigration OR (climigration OR klimamigration)) OR asylmigration) OR remigration).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(((kernmigration or (climigration OR klimamigration)) or asylmigration) or remigration)".
• Adding a wildcard symbol may retrieve word variants: (((kernmigration or (climigration OR klimamigration)) or asylmigration) or remigration)*.