From Wikipedia,
the free encyclopedia.
MEDLINE (Medline,
Medical Literature Analysis and
Retrieval System Online) is a
comprehensive literature
database of life sciences and
biomedical information. It covers
the fields of
medicine,
nursing,
dentistry,
veterinary medicine, and the
health care system. As perhaps a
side effect of covering these
fields, it also manages to cover
nearly all of biology and
biochemistry, even covering fields
with no direct medical connection,
such as
molecular evolution.
It is compiled by the
National Center for Biotechnology
Information (NCBI) of the U.S.
National Library of Medicine (NLM)
and freely available on the
Internet through PubMed,
searchable with the
Entrez engine.
The database
The database contains over 14
million records from more than
4,800 different publications
(mainly
medical journals) from the
1950s to today, and new
citations are added daily.
Newer citations include abstracts
of the article in question. It is
designed to have global coverage,
but most records are from
English-language sources or have
abstracts in English.
MEDLINE uses
Medical Subject Headings (MeSH)
for information retrieval. Engines
designed to search MEDLINE (such
as
Entrez) generally use a
Boolean expression combining
MeSH terms, words in abstract and
title of the article, author
names, date of publication, etc.
Entrez allows also to find
articles similar to a given one
based on a mathematical scoring
system that takes into account the
similarity of word content of the
abstracts and titles of two
articles.
Impact
MEDLINE functions as an
important resource for biomedical
researchers and
journal clubs from all over
the world. Along with the
Cochrane Library, MEDLINE
facilitates
evidence-based medicine. Most
systematic review articles
published nowadays build on
extensive searches of MEDLINE to
identify articles that might be
useful in the review. Many
articles mention the terms that
have been used to search MEDLINE,
to make the search reproducible
for other scientists.
Additionally, MEDLINE
influences researchers in their
choice of journals in which to
publish. Few researchers today
would consider publishing in a
journal not indexed by MEDLINE
because then other researchers
would not find (and cite) their
work.
Medline indexing
Selection of journals for
Medline does not have an objective
set of criteria. Selection is
based on the recommendations of a
panel, the Literature Selection
Technical Review Committee (LSTRC).
The decision whether or not to
index a journal is ultimately the
responsibility of the Director of
the
National Library of Medicine.
The selection involves
considerations of both scientific
policy and scientific quality.
Publication of objective
criteria for inclusion of medical
journals is long overdue as
perceived subjectivity may lead to
Medline being replaced by more
modern alternatives, such as
Google scholar. However, the
LSTRC selection committee are
themselves chosen by US government
officials. The process is thus
open to institutional bias and the
selection of journals has been
described as a means of censorship
in medicine. The
Journal of orthomolecular medicine
has been repeatedly refused
indexing over a period of 35 years
leading to claims of bias by Dr
Abram Hoffer and Dr Andrew
Saul amongst others. Such bias
against
orthomolecular medicine was a
well described feature of the
later years of the chemist
Linus Pauling who named the
discipline. Notably, the Journal
of Nutritional and Environmental
Medicine which is supported by the
British Society for Ecological
Medicine has also been refused
indexing on both occasions it
applied.
Usage
Although it seems simple,
searching Medline effectively is a
learned skill. Without some
training it is easy to become
frustrated by the amount of
articles a simple search turns up.
Contrarily, it is difficult to be
sure that the search is
comprehensive, even if it has
collected thousands of articles.
There are
tutorials on using the PubMed
interface which explain the ways
to get the best out of the site.
However, the key skill, framing
the correct search string, is not
so easily taught. The librarians
classify all articles according to
subject matter using a
standardized vocabulary to
describe the subjects - Medical
Subject Headings (MeSH). Using the
MeSH database to define the
subject of interest is one of the
most useful ways to improve the
quality of a search. Finding one
article on the subject and
clicking on the "Related Articles"
link to get a collection of
similarly classified articles is
another.
