I first clicked on the "medicine" link in the subjects area, and chose the Encyclopedia of Medicine. After a couple of searches, I was disappointed because 0 results were being returned! Eventually, I learned that I was using the "search within results," rather than starting a new search (so all previous limits and search terms were still being applied).
Once I figured out how to start a new search from scratch, the results were much more reasonable.
I went back to the home page, and typed "nighthawk" in the general search box at the top of the page. Much to my pleasant surprise, the first result was:
I opened the first result link, and wanted to try the "read to me" feature, but it took me a while to locate the cryptic "listen" tab (this feature could benefit from an icon). The voice-over was very smooth, and not too robot-like. A great feature for students with learning/reading disabilities (or anyone who needs "eyes-free" reading).