Many physics constants are available to you to click on and copy and paste into the calculator main screen. Below are some of these units that are offered to you. It is not intended to be an authoritative source, the more complete list at http://physics.nist.gov/cuu/Constants/index.html
Feel free to Download the program and give it a try!
Questions, comments? send me an email: bdwhaley@scienceshareware.com