Revit uses TrueType Fonts that are available to all programs. AutoCAD uses SHX files which were only written for AutoCAD. Symbols that are available for any given font strictly depend on the font used (for example whether Diameter or Centerline symbols are available).
If you go to your windows start menu and in the “Search programs and files” type in CHARMAP (run it)… it will show all the special keys available for any TTF you are using. You can select the symbol you are interested in and bottom right hand corner will display the keystroke code for revit (i.e. degree symbil is Alt+0176).
You can also use Copy and Paste method (Ctrl+C and Ctrl+V).