DocumentationMathematicaFront EndMenu CommandsHelp Menu
Find Selected Function...
Find Selected Function opens the Help Browser with the Built-in Functions radio button selected.
The Help Browser lets you access a wide range of notebooks and other material to get help while you are using Mathematica.
Keyboard shortcuts: F1 (Windows); f (Macintosh); F1 (X).
See The Mathematica Book: Section 1.3.8 and Section 1.3.9.