When you have Service Desk integrated with a Confluence Knowledge base you can see search results for related articles from within JIRA. However these search results appear to be limited to only 3 results in this view. Conversely looking at the confluence space directly results many more search results.
It would be nice if within the project configuration within Service Desk that you could customize the number of expected search results. At the moment this does not appear possible.
Current method of using the Label restrictions might be helpful in some cases, but it does not allow for more results to be displayed.