Crawled share not showing up in search results

I have a distributed Sharepoint 2013 Search infrastracture as the image below show:

I crawled like 20 shares successfully. But I'm experiencing the following problem.

After creating an Enterprise Search Center when I do a search I obtain results for some shares and for some others no. The share on which I'm experiencing problem have thousand of items successfully crawled according the crawl log.

I would like to understand where the problem is but I ran out of idea. Do you have any suggestions on how to debug and troubleshoot such a problem?