I recently posted about the twentieth anniversary of the patent search database called Espacenet. It really is a great resource for informing commercial and R&D decisions, as well as patent ones.
The search functionality on Espacenet has recently been improved under this new beta version. It puts more tools at your fingertips than ever before.
There's also a short introductory video showing you how to make the most of it.
This is a beta version of Espacenet