Transcript Dr. Ali M. Hadianfard Paramedical School, AJUMS

Dr. Ali M. Hadianfard
Paramedical School, AJUMS
http://www.alihadianfard.info/download.html
The Internet is a vast
sea of information.
some of it is useful,
relevant, authoritative,
and some of it is not.
That is why “Surfing”
the World wide web
requires knowledge
and skill.
INFORMATION OVERLOAD!
How can I
make my
search more
specific?
Why I’m getting
these results!?
How can I search
better and get
There’s too much
quality information?
Information here!
Most of the
documents I
retrieve aren’t
relevant to my
query.
WE SHOULD IMPROVE
THE WAY OF SEARCHING
ON THE INTERNET
FOUR TECHNIQUES
 Focus
 Use
your subject clearly
Meta- search engines
 Use Advanced
 Use
features
Directories
QUERIES
Queries are the combination of
keywords and operators that
we enter into the search box of
search engines.
Example:
computer + “clinical decision support
systems”
THE OPERATORS AND SYNTAX IN BOOLEAN
SEARCHING
OR: terms on either side of this operator are
sufficient to be scored as a result.
 AND (+): terms on both sides of this operator
must be present somewhere in the document in
order to be scored as a result.
 NOT (-): documents containing the term after this
operator are rejected from the results set.
 NEAR: similar to and, only both terms have to be
within a specified word distance from one
another in order to be scored as a result.

…CONTINUE
Phrases (“”): combined words or terms that
must appear directly adjacent (exact) to one
another and in the phrase order for the
source document to be scored as a result.
 Parentheses: nested operators that are
evaluated in an inside-out order of
precedence.
 Wildcards (*,?): beginning characters
(stemming) that must match the same
beginning characters in a document's words
in order to be scored.

SOME EXAMPLES



Use of Boolean Operators: AND, OR, NOT, NEAR

diabetes AND mellitus

cancer OR tumor

diabetes NOT insipidus

Application NEAR “multimedia patient record”
Use of phrase and parentheses

“medical device failure”

(“acute heart disease” +ischemic) OR (“chronic heart disease”
AND hypertension)

(diabetes AND mellitus) -complication
Use of truncation

Cardio*
cardiovascular, cardiothoracic,…
EXAMPLES OF SEARCH ENGINES
 http://www.altavista.com
 http://www.lycos.com
 http://www.hotbot.com

http://www.bing.com

http://search.yahoo.com
 http://www.google.com
 http://www.ask.com
SEARCH ENGINES ARE GOOD FOR...

Finding a lots of information.

Addressing a fairly specific
information.

Searching a specific type of
information such as images
SOME POPULAR META-SEARCH ENGINES
 Mamma
http://www.mamma.com
 IxQuick
http://www.ixquick.com
 Excite
http://www.excite.com
 Metacrawler
http://www.metacrawler.com
 Dogpile
http://www.dogpile.com
 Search
http://www.search.com
DIRECTORIES
Search directories operate
based on a subject
classification scheme or
taxonomy. Also is named
Subject index
SUBJECT INDEXES ARE GOOD FOR..

Accessing to quality information.

Addressing more general information.

obtaining a general overview of what’s available for a
particular subject area.

Organising information more effectively.

information sources are categorised according to their
content
EXAMPLES OF SUBJECT DIRECTORIES
http://www.dmoz.org
http://www.about.com
http://directory.yahoo.com
Getting to the right level