USPTO recently launched a web-based tool for searching patent data of past 40 years (1976-2014) named Patentsview.org
The tool is a great approach by USPTO to expand the reach of its resources to everyone. Patentsview allows user to dig through huge patent data, retrieve top assignee and inventors, view a timeline of particular class, graphical view of emergence of a technology and what's not.
But, it is still in beta version and need some improvement. In cure for that and provide you some pro tips I am sharing this link to use this tool easily. The tool provides a wide variety of search criterias and allows to search for patents via geographical coordinates.
Here is the link to article - 6 HIT AND MISS OF PATENTSVIEW THAT YOU SHOULD KNOW
Must read and give your feedback about the tool.