C Programming in Visual Studio - Go To Definition Descriptions

No, you cannot get the source code directly from your system/PC because the library files are first compiled and then stored as .a(Unix) or .lib(Windows) static files / .so(Unix) or .dll(Windows) dynamic files.
Note: Similar answer is mentioned in the comment section as well by others.

However, you can download the source codes of various implementations. For starter, you can go to GLIBC and download the source code from there. Instructions to download are mentioned on the website itself.

There is an index to a list of detailed function descriptions, discussion, and in some cases example code in the Microsoft alphabetical function reference.

This is surely of much more practical use than looking at the source code to find out what the library functions do.