I’ve just written some “search plugins” for Firefox (1.x and 2.x) that allow you to quickly look for a specific Digital Object Identifier (DOI). These DOI are more and more used in biomedical sciences. One of their interesting features is that they allow direct linking to the scientific article.
The plugins are availble here. If you already have Firefox 2, the installation procedure is very easy: all you have to do is go to the plugins page, click on the small arrow near your Firefox search box and choose the “Add DOI lookup” option; it will then automatically be installed for you.