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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!
There’s too much Information here!
Why I’m getting these results!?
How can Imake my search morespecific?
Most of the documents Iretrieve aren’trelevant to myquery.
How can I search better and get
quality information?
WE SHOULD IMPROVE THE WAY OF
SEARCHING ON THE INTERNET
FOUR TECHNIQUES
Focus your subject clearly
Use Meta- search engines
Use Advanced features
Use Directories
which subject is the best subject for searching?
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”
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.
THE OPERATORS AND SYNTAX IN BOOLEAN SEARCHING
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.
…CONTINUE
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
THANK YOU