Yes. Uwe Ligges' R Help Desk article in this Rnews should answer your  
questions:
www.r-project.org/doc/Rnews/Rnews_2006-4.pdf
On Jun 4, 2009, at 9:08 AM, Karin & Martijn wrote:
> Hello,
>
> Can anyone help me with the following:
> if one enters a function name in the R console then usually one sees  
> the code of that function. But there are functions that one cannot  
> see. For example I want to see the code of print.htest or  
> t.test.default. These functions are non-visible. Is it possible to  
> see the code anyway?
>
> Thanks in advance,
>
> Karin Groothuis-Oudshoorn
David Winsemius, MD
Heritage Laboratories
West Hartford, CT