Science-advisor.net is a free search engine addressed to researchers and students.
Science-advisor.net is a scientific database where researchers or students can search for scientific literature, and at the same time can freely and anonymously discuss and review research articles.
The search engine uses also metadata harvested following the open archives initiative protocol.
Get alerted when an article is publishe in your field of interest.
You can search and download all articles of arXiv.org (physics, mathematics, computer science), PubMedCentral (biology, medicine) and some important contributions from PubMed.