Change to the directory RegistryDomain-base/domains/registry/applications/j2ee-modules/soar/WEB-INF/classes.
Open the file jaxr-ebxml.properties in a text editor.
Find the definition of the property omar.client.thinbrowser.numSearchResults:
omar.client.thinbrowser.numSearchResults=25
Change the value 25 to the value you prefer.
Save and close the jaxr-ebxml.properties file.
Follow the instructions in To Stop and Restart the Application Server Domain for the Registry.