I've used some tips about how to toy with the format of backrefs in biblatex, and I'm seeing that the formatting is quite flexible. In the screenshot below, I've put the backref into a box. That's fun, but I'd like the backref to appear after the period, i.e., after the entire citation, like this:
- M. Nowak, Science 314, 1560-1563 (2006). See p. 1
Not like this:

MWE:
\documentclass{article}
\usepackage{filecontents}
\usepackage[natbib=true,
hyperref=true,
url=false,
style=science,
sorting=nyt,
autocite=superscript,
isbn=false,
backref=true,
maxcitenames=3,
maxbibnames=100,
block=none]{biblatex}
\DefineBibliographyStrings{english}{%
backrefpage = {See p.}, % for single page number
backrefpages = {See pp.} % for multiple page numbers
}
\renewbibmacro*{pageref}{%
\iflistundef{pageref}
{}
{\printtext{%
\fbox{
\ifnumgreater{\value{pageref}}{1}
{\bibstring{backrefpages}\ppspace}
{\bibstring{backrefpage}\ppspace}%
\printlist[pageref][-\value{listtotal}]{pageref}
}}}}
\usepackage{hyperref}
\begin{filecontents}{references.bib}
@article{nowak2006five,
title={Five rules for the evolution of cooperation},
author={Nowak, M.A.},
journal={Science},
volume={314},
number={5805},
pages={1560--1563},
year={2006},
publisher={American Association for the Advancement of Science}
}
\end{filecontents}
\bibliography{references.bib}
\begin{document}
Evolutionary games.\supercite{nowak2006five}
\printbibliography
\end{document}
Update I've tried the fix from Guido in the accepted answer below -- it works with my MWE, but introduces another problem when there is more than one bibliography entry (see MNWE). I expect it just needs minor changes...


\renewcommand{\finentrypunct}{}seems to do a better job of avoiding the period at the end without causing any chaos, see http://www.khirevich.com/latex/biblatex/ – Joe Corneli May 09 '13 at 15:26\finentrypunctis indeed the way to go;\finentrydoes more than just print\finentrypunctand it should be executed at the end of every bibliography entry. – Audrey May 09 '13 at 15:47\finetrypunctleave entries withoutpagerefwith no final period. – Guido May 09 '13 at 21:10