Bibliography items are inserted using \pgfuseimage which is a wrapper for \includegraphics. The basic three items used in the bibliography include
beamericonarticle
beamericonbook
beamericononline
To include these in your regular frames, either use \pgfuseimage, or scale the icons as needed with an explicit \includegraphics:

\documentclass{beamer}
\begin{document}
\begin{frame}
Print the article bibliography icon here or use it as item bullet in a list.
\begin{itemize}
\item Article: \pgfuseimage{beamericonarticle}
\item Book: \pgfuseimage{beamericonbook}
\item Online: \pgfuseimage{beamericononline}
\item[{\includegraphics[scale=.75]{beamericonarticle}}] An article
\item[{\includegraphics[scale=.75]{beamericonbook}}] A book
\item[{\includegraphics[scale=.25]{beamericononline}}] An online reference
\end{itemize}
\end{frame}
\end{document}