Siri may have improved a lot since its launch in 2011, but the lack of a "back" button on some of its results can be infuriating. This especially true when you're searching for places such as local restaurants. There is a back button on the "Details" page for each individual restaurant that takes you back to your original query, but there is no way to go back once you have accessed the Maps app for directions.
It seems like a no brainer that you should be able to return to the original Siri results without having to ask the same question over and over. However, this does not work anytime you leave Siri to open a separate app. You can however get back to your original search results by following these instructions:
After you are done getting directions or checking Yelp reviews for an individual restaurant, hold down your Home button to once again evoke Siri. But instead of asking the same question a second time, just swipe down when you see the black Siri screen. This will allow you to scroll up and access the results to your last query.
This is still not as helpful as a back button, but it is easier than asking Siri the same question several times until you find what you're looking for. This technique also helps you avoid any Siri mistakes and will ensure that you get consistent results.