For all parameters, please refer to the Autodesk Nastran Reference Manual:
Start > All Programs > Autodesk > Nastran > Documentation > Autodesk Nastran Reference Manual
Section 2 of the Reference Manual has all of the different Parameters.
Find option allows you to find the parameter. In the Find window you can select and right-click the parameter and click Go to Param. It will take you to the respective Param or Directive.