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