Just click the + next to "Show options" to see the available filters and views you can apply to your search results. Click "Hide options" to remove the options panel from view.
You can slice and dice your results to find different types of content (like videos and reviews), or results fitting a date range (the most recent results or results from a specific time period). It even lets you filter out commercial results by choosing "fewer shopping sites".
Read more about it at the Google Help: Features page or watch this short video: