Click up on the Library-Tools link on the library's home page http://library.drake.edu/ and then click on Databases. Click on D & scroll to Dynamed.

Update:
The library's website has since been updated, and the steps for accessing Dynamed are as follows:

1. Go to the library home page, http://library.drake.edu/
2. Click on Find > Article Databases (http://library.drake.edu/find/article-databases)
3. Type 'Dynamed' into the Search by Database Name field, or click 'D' in the A-to-Z list.
4. Click the Dynamed link.

Here is the direct link to Dynamed.