From: "Hamill, Cheryl" <[log in to unmask]>
Date: Tue, 18 Sep 2012 09:53:17 +0800
Use of double quotes in PubMed turns off the automatic term mapping and
is very limiting. It will ONLY search terms that are in the PubMed
phrase index:
http://www.nlm.nih.gov/pubs/techbull/jf11/jf11_skill_kit_pm_phrase_searching.html
http://www.ncbi.nlm.nih.gov/books/NBK3827/#pubmedhelp.Searching_for_a_phra
" Warning! Searching a phrase using double quotes turns off automatic
mapping to MeSH terms. For example, "heart attack" will not map to the
MeSH term Myocardial Infarction, whereas, heart attack will.
One final note: Not all phrases are recognized in PubMed, e.g.,
emotionally disordered. In this case, the search results will be the
same for Steps 1 and 2. Without quotes emotionally disordered is
searched as:
emotionally[All Fields] AND disordered[All Fields]
Likewise, with quotes "emotionally disordered" is searched as:
emotionally[All Fields] AND disordered[All Fields]
When a quoted term is not searched as a phrase, the following message
appears above the search results:
Screen capture of citationcontext menu. eg Quoted phrase not found."
PubMed is a wonderful database - high quality with many extremely useful
features. There is no comparison between it and google scholar for most
searching in medicine by experienced searchers. The data from PubMed
that is used in other interfaces (eg Ovid) provide alternative interface
options that all have a different range of benefits. Searchers tend to
develop a preference for one or another mostly based on their in depth
experience with the interface. GoogleScholar has many benefits too but
as many have observed, it is a matter of the best tool for the job and
for the exercise of judgement on which to use when. Clients may well
find google scholar easier and quicker and many libraries have enhanced
this search experience by embedding openURL resolvers into it so the
discovery experience is seamless.
Cheryl Hamill | Librarian in Charge
Fremantle Hospital and Health Service | SMHS
T Block, 2nd floor, Alma Street, Fremantle WA
[log in to unmask]
www.fhhs.health.wa.gov.au/library
-----Original Message-----
From: "Sanders, Susan U." <[log in to unmask]>
Date: Sat, 15 Sep 2012 22:32:12 +0000
For clarification in speaking about searching PubMed.gov, and mapping to
MeSH, try this:
Use the words heart attack (without quotes). I retrieved 186,831
citations. Look in the Search Details at your query translation and
you'll see the way that the PubMed system ran the search, like this:
"myocardial infarction"[MeSH Terms] OR ("myocardial"[All Fields] AND
"infarction"[All Fields]) OR "myocardial infarction"[All Fields] OR
("heart"[All Fields] AND "attack"[All Fields]) OR "heart attack"[All
Fields]
Try using the MeSH subject heading Myocardial Infarction. I retrieved
136,867 citations.
PubMed uses "Automatic Term Mapping," see here for explanation:
http://www.nlm.nih.gov/bsd/disted/pubmedtutorial/020_040.html
If you use heart attack, PubMed "maps" the term to MeSH and also
searches to retrieve phrases and individual terms that are in All
Fields, hence more citations than if you used a MeSH term. What MeSH
gets you is a more specific set of results. What keywords gets you (all
fields) is a more sensitive retrieval, but with more irrelevant
citations.
Best,
Susan
Susan Sanders
Clinical Medical Librarian
University of Missouri Kansas City
________________________________________
From: Linda Schwartz <[log in to unmask]>
Date: Fri, 14 Sep 2012 07:19:17 -0400
I find one point in Cynthia's posting misleading. PubMed does not
convert keywords like "heart attack" to MESH headings. MESH headings are
a more powerful way to search and can be searched through PubMed.
Try both searches in the basic search box and you will get at least
5,000 hits difference in retrieval. (Using quotes around each phrase
makes the retrieval difference even more extensive!)
I think Paul's statement is spot on. GScholar content is less reliable
- not unreliable but less reliable - requiring MORE analysis that I
personally do not hear users doing. Also important is the algorithm upon
which retrieval in Google Scholar is based rewards popularity - even if
that popularity is based on a bad work that has been cited repeatedly
because it is so poorly done!
Educating the user is important. GScholar is just one tool in the box
and you need to know how each tool works, its strengths, its weaknesses,
and its coverage and apply time for analysis of results.
Unfortunately, users do not educate themselves but rely on the tool to
translate their words into an effective search - without bothering to
find out if it really does so.
Linda Matula Schwartz, MDE, AHIP
Director, Library Services
Lehigh Valley Health Network
Allentown, PA 18105
-----Original Message-----
From: Cynthia Porter <[log in to unmask]>
Date: Wed, 12 Sep 2012 12:44:39 -0700
Thank you Ken, I'm glad you asked this question. I've been thinking
about Google Scholar lately.
I work in a medical library and I like searching in PubMed because it
converts keywords to Medical Subject Headings (MeSH), so it goes beyond
a keyword search (e.g., I search "heart attack" but I get all the
articles with the MeSH "Myocardial infarction"). Doesn't Google Scholar
depend on matching keywords?
Several times I have encountered full text links to journal articles in
Google Scholar for items that are not available online from our library.
I think that some of these resources were posted without publisher
consent. Is it wrong to refer a student to this online resource? I've
sent the link to students, but not a copy of the document. This
practice just doesn't feel right to me. I guess I could tell the
student to search it themselves in Google Scholar, but I don't like it
when people tell me to "Google it."
Cynthia
Cynthia Porter
[log in to unmask]
Distance Support Librarian
A.T. Still Memorial Library, Arizona
Mesa, AZ 85206
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