Google Scholar enables you to search specifically for scholarly literature, including peer-reviewed papers, theses, books, preprints, abstracts and technical reports from all broad areas of research...
...Just as with Google Web Search, Google Scholar orders your search results by how relevant they are to your query, so the most useful references should appear at the top of the page. This relevance ranking takes into account the full text of each article as well as the article's author, the publication in which the article appeared and how often it has been cited in scholarly literature.
One advantage over pubmed, if there is one, is fewer clicks to get to a pdf of an article. Although I suspect their article rankings will be greeted with some skepticism, at least so long as their ranking algorithms are kept secret.
Back in June, I wrote about Google's usefulness to medicine:
I just met a toxicology student who, when confronted with a novel patient ingestion, has more luck with google than pubmed. And he's not the only scholar using Google results for urgent patient care...
Google is a private company, of course, and they provide a free service that works very well. But if the internet is becoming the central repository of human discourse, and Google is the indespensible guide to the internet, there should be more transparency about how it works. Why do some terms rise and fall, while others disappear and come back? The answers might be of trivial importance now, but someday it could be lifesaving...
...The bottom line is, will scientists and scholars remain content if their reference librarian pulls books and journals out of a black box and says, "trust me, this is what you want" ? Maybe... But only if they're always, always right.
We'll soon see. In the meantime, let the academic ego-jockeying begin! Are you really the top expert in your tiny little field?