Launched in April 2001 by Elsevier, Scirus (http://www.scirus.com) claims to be the most comprehensive scientific, technical, and medical (STM)-specific search engine available on the Internet. Scirus covers more than 167 million Web pages and says it can pinpoint STM information that other search engines cannot reach. Scirus also covers more than 18 million full-text articles and abstracts from sources such as MEDLINE, ScienceDirect, BioMed Central, pre-print servers, as well as patents. The proprietary content always contains a free layer of information, such as a journal abstract, which is accessible by users.

Just this week, Scirus announced that it has partnered with the American Institute of Physics (AIP) to index AIP's full-text articles. Scirus had previously indexed just the AIP abstracts. AIP content found on Scirus will direct users to Scitation.org, the AIP's new online hosting service—the online home to more than 140 journals from AIP and other science and engineering societies. Institutional and individual subscribers will automatically have access to the full-text articles of their subscribed journals via links from Scirus.

While Google is definitely pulling in publishers for its Google Scholar initiative, Vogtlander said it is not a real competitor to Scirus. "Google is a huge brand for good reason—it's good for general purposes, but it's still frustrating for scholarly research." She said that there are several key factors that distinguish Scirus from general search engines and even from Google Scholar: unique content, superior indexing and classification technology, and advanced search capabilities.

As for content, Vogtlander said that Google Scholar focuses on access to published content in journals, while Scirus excels at providing access to both published and unpublished resources, including: 

• University pages (domains ending with .edu, .ac.uk, and educational sites within other countries)
• Scientific organizations (.org) and conference pages
• Company pages with scientific R&D information or information relevant to researchers (.com)
• Government pages dealing with science, including health and sciences like law (.gov)
• Scientist and author home pages

In addition to Web pages, Scirus indexes a number of journal sources, pre-print servers (clearly labeled as pre-prints to distinguish from peer-reviewed articles), patent sources, repositories, and databases. It includes diverse resources like lab results, technical reports, and courseware. Vogtlander said, "Scirus makes it clear to users where the content comes from and whether it's validated."

As to its indexing technology, Scirus maintains a customized linguistic knowledgebase for each subject area it covers and uses a classification process to improve retrieval. Elsevier developed Scirus with Fast Search & Transfer (FAST) and continues to refine the technology used for its specialty engine. It also works closely with its information partners, like scholarly institutes and organizations, on doing the best job in exposing the content by crawling and extracting metadata.

Finally, Vogtlander pointed out the advanced search capabilities of Scirus. Advanced search options include:

• Select from a range of 20 searchable subject areas spanning health, life, physical, and social sciences.
• Locate data within a specified date range.
• Search by information type, such as scientific conferences, abstracts, and patents.
• Search within specific information sources, such as journals on BioMed Central or a Web source such as NASA.
• Search by journal title, article title, or author name.

At this point, Google Scholar does not offer advanced search options—just a basic search box. But, as Vogtlander acknowledged, it is still a beta product and will undoubtedly improve and add content from additional publishers and information producers. And there's that enormous brand recognition for Google among the general public. This is compounded by the lack of knowledge, even among educators and researchers, of specialized sources like Scirus and the rich databases and resources freely available through libraries. 

The real message, perhaps, should be to understand the research tools and what each does best (i.e., don't use a hammer when a wrench is needed). Scirus, Google, and professional online services all have specific search strengths to offer. Librarian David Dillard of Temple University pointed out this benefit: "At the very least Google Scholar will provide a place to explore literature topically and get a sense of what is written before approaching databases with more involved search strategies and also provide another court of appeal to find or add to results to searches tried elsewhere in the database world."

But, for Web searchers in the know, Scirus can be a gold mine for serious science research.