While Google tweaks its search engine algorithm constantly, so an upgrade means you're getting a different strategy for finding health data, Bing uses search partners to define results in reaction to keywords.
(Picture from Bing.)
Not that an old-fashioned keyword search on the main Web search engine won't yield results. I just typed in ARBs, was given the full name of the drug type, and found the third result is a recent CBS story on their possible link to cancer. (Disclosure: ZDNet is owned by CBS.)
In the new health service data comes in a block form, combining links to articles from partners like the Mayo Clinic, a short list of conditions and commonly-prescribed medicines and (sometimes) a related tweet, usually a link to a news story.
The site has also added some new content partners, Harvard Health and the CDC.
The idea is that Google can be a search engine while Bing becomes a find engine, with one-click access to authoritative information from partners, rather than a string of search results.
A search on a common medical test like the CRP test (for C-reactor Protein) now leads directly to a data box showing what common scores mean. A search for clinical trials leads directly to a chart leading to lists of open trials from Clinicaltrials.gov.
The idea of Microsoft building a health vertical from within its search engine should not surprise. Bing Health is an outgrowth of Medstory, a company Microsoft bought in 2007. It was originally known as Live Health Search and was seen as a front-end to Microsoft HealthVault.
While most Bing marketing has been horizontal, using TV ads and even content on shows like The Colbert Report, expect more vertical-oriented marketing as the engine builds more vertically-oriented sites like Bing Health.