There are a couple of places where you can access citations for articles found within PubMed.
1. Search Results page - Click the Cite link beside the result
2. Article Details page - Click the Cite button under 'Actions'
Clicking the Cite link or button will open the Citation Text pop-up. Here we can see a preview of the citation. There are actions across the bottom of the box.
You can export records from PubMed to your RefWorks account (More about RefWorks). There are two ways to do this.
Single Record: download a single .nbib file from the Citation Text popup (as we saw in the previous box)
Multiple Records: