You can use the help to get the list of available modules:

>>> help("modules")

Please wait a moment while I gather a list of all available modules...

	  

To search through the documentation of modules for a specific word, for instance "SProt", also use the help command like this:

>>> help("modules SProt")

Here is a list of matching modules.  Enter any module name to get more help.

Bio.SwissProt.KeyWList - KeyWList.py
Bio.SwissProt.SProt - SProt.py
Bio.SwissProt (package) 

	  

The sys also contains the dictionary of loaded modules.