Google推出专门为科学工作者服务的搜索引擎

Google推出专门为科学工作者服务的搜索引擎

Site:
http://scholar.google.com

News@Nature-Nov 18,2004-Scientists get their own Google

Imagine searching the Internet and being able to restrict your results to
acad
emic texts. Today Google launched a free search engine that aims to do just
th
at. Google Scholar searches only journal articles, theses, books,
preprints, a
nd technical reports across any area of research.

A test version of the search engine is available at
http://scholar.google.com
so you can try it out. In a search for the phrase "human genome", for
example
, a normal Google web search throws back 450,000 or so hits, with genome
centr
es and databases and other websites ranked top.

In contrast, Google Scholar returns just 113,000 hits, and all the
top-ranked
items are not websites but seminal papers on the subject. In fact, the
number

one hit is the landmark article "Initial sequencing and analysis of the
human
genome"1 published in Nature in 2001.

The tool is based on principles similar to those of Google's web search.
The o
riginal search manages to make the most useful references appear at the top
of
the page using algorithms that exploit the structure of the links between
web
pages. Pages with many links pointing to them are considered
'authorities', a
nd ranked highest in search returns.

The ranking is refined by taking into account the importance of the origins
of
links to a paper. "We don't just look at the number of links," says Sergey
Br
in, a cofounder of Google. "A link from the Nature home page will be given
mor
e weight than a link from my home page," he explains.

Google Scholar works in much the same way, using the citations at the end
of e
ach paper, rather than web links. It automatically identifies the format
and c
ontent of scientific texts from around the web, extracts the references and
bu
ilds automatic citation analyses for all the papers indexed.

This approach has been pioneered in computer science by ResearchIndex,
softwar
e produced by the information technology company NEC.

Much of the peer-reviewed material has been made available to Google by
publis
hers, including Nature Publishing Group, the Association for Computing
Machine
ry and the Institute of Electrical and Electronics Engineers, through a
pilot
cross-publisher search engine called CrossRef Search.

Publishers have arranged for Google robots to scan the full texts of their
art
icles. Users clicking on a hit returned by Google Scholar are directed to
the
article on the publisher's site, where subscribers can access full text and
no
n-subscribers get an abstract or information on how to buy an article.

Google Scholar has a subversive feature, however. Each hit also links to
all t
he free versions of the article it has found saved on other sites, for
example
on personal home pages, elsewhere on the Internet.

Resource:
http://www.nature.com/news/2004/041115/full/041115-13.html

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Google推出专门为科学工作者服务的搜索引擎