Quertle: the biomedical search tool

BioMed Central, the world's largest open access publisher, has teamed up with Quertle LLC to add over 60,000 published articles to Quertle, the online biomedical search tool. Instead of simple keyword searching, this search engine uses a combination of linguistic methods to produce more relevant results. As well as searching fulltext documents from BioMed Central, it also searches PubMed, with other fulltext sources to be added in the near future. Quertle was created by biomedical scientists and chemists, to address the needs of researchers working with this technical literature.

You can try out the search engine here: http://www.quertle.info/