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Choosing the best Keywords and Phrases to Search
Knowing when to Search a Subject
What's the difference: Keywords and Subjects?
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Chosen by you: should be unique to your topic and include the
main ideas that you'd like to research. |
Determined by others: also known as controlled vocabulary or Library
of Congress Subject Headings, subject headings organize where and how information is
cataloged and located. |
Good for simultaneously searching several topics. |
Good for searching a specific topic. |
Can include obscure or recently-coined phrases and slang. |
Only formal, structured, and traditional terms used. |
Will return search results that are irrelevant to your
information needs. |
Search returns will always be relevant (the benefit of
cataloging/organizing materials by consistent subject). |
Keywords are easily determined: just think one up! |
Correct subject headings are harder to determine because
they are controlled. Know where to look (see below). |
Keywords
• Remember, keywords are simply words that describe or relate to your research topic.
You determine what you think are the best keywords.
• When you keyword search in a library catalog or database, you can choose to look through many
fields—title, author, subject, abstract etc.—to locate material records that mention your
search term(s).
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Adverse Effects of Obesity on Anesthetized Patients
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anesthesia, obesity, overweight, surgery, complications
(or any variation/synonym of these words) |
Starting a Business in Afghanistan |
Afghanistan, business, foreign investment, labor, unemployment, market
forces, starting up |
Phrases and Search Tips
• After you construct a solid list of keywords, you may discover that searching
one word at a time nets too many results, of which many are irrelevant to your search. This is when
knowing how to search with phrases becomes useful.
• Combine your keywords into "search strings."
• Search strings effectively narrow your results to include a manageable number of more
specific, relevant results.
• You may want to search for a specific phrase, such as Nurse Anesthesia or Gastric
Bypass Surgery. Enclose the words with quotation marks. This tells the index to search
for those specific words in order.
search Gastric Bypass Surgery |
search "Gastric Bypass Surgery" |
• Nets results including one or all of the search terms, not necessarily in their original order
• Decreased search result relevancy
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• Nets only results including the exact phrase "gastric bypass surgery"
• Increased search result relevancy |
• You can also search for longer phrases and multiple keywords using the
Boolean search terms AND, OR, and NOT.
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AND
Placing and between two or more keywords narrows your search.
And tells the catalog/database to retrieve only results including all
of the keywords you enter.
• Searching obesity AND "anesthesia complications" nets results that
contain both the search term and search phrase.
• Number of search results decreases.
• Relevancy increases.
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OR
Placing or between two or more keywords broadens your search to include at least
one of the search terms, if not both.
• Searching obesity OR "anesthesia complications" nets results that
contain one or both search terms.
• Number of search results increases.
• Relevancy decreases.
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NOT
Placing not between search terms excludes specific terms from your search results.
• Searching "anesthesia complications" NOT obesity returns results that do not
contain the term obesity anywhere in the text of the document.
• Number of search results decreases.
• Relevancy increases.
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• Another way to expand your search is to truncate it. Truncation
locates multiple forms of a word, including various spellings and different endings. By adding an
asterisks (*) to the end of the root word, search results will include any applicable variation of
your search term (in most cases—the use of an asterisks for truncation can vary in databases—also
try using !, ?, or # for truncation ).
Truncated search: *depress*
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Results include: depress, depressing, depression, depressed, depressive,
antidepressant
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Results include: depress |
Truncated search: an*esthesia |
Normal search: anesthesia |
Results include: anesthesia and anaesthesia |
Results include: anesthesia |
Subject Headings
• Subject, or controlled vocabulary, searches are the best way to locate information about a
specific topic.
• Topics are assigned appropriate subject headings for organization and retrieval purposes. Thus
when you select a certain subject heading, you will only retrieve relevant, topic-specific results
that were tagged with that certain subject heading. No need to worry about weeding out irrelevant
or useless results!
• However, in order for a subject search to be successful, you need to know where to locate the
correct subject term or phrase for your topic.
• Subject headings/controlled vocabulary are determined by the Library of Congress. Accessing these
terms is easy.
Finding Subject Headings in the Library Catalog
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Go to SMU’s
Library Catalog and perform a keyword search. Choose a book or other item
relevant to your topic. |
Bring up the catalog record of the item (by clicking on the title). |
Scroll down: the subject headings/controlled vocabulary are listed
under "subject." |
• Select a relevant subject heading (I chose the first one,
Anesthesia – Complications).
• Continue searching by clicking on the subject heading link.
• The page to the right appears—you are now subject searching the library catalog for
all materials tagged with the anesthesia—complications subject heading.
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• You’ve completed a subject search! Each result returned deals directly with anesthesia and
complications—you do not need to worry about weeding through irrelevant, useless, or
accidental results.
• Added bonus—you can use each subject term in future searches, and not just in SMU’s library
catalog either. Because subject headings are controlled, they are used uniformly in all library
catalogs as well as most databases.
Finding Subject
Headings in a Database (varies)
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Go to SMU's
Search for Articles link, select a database, and perform a keyword search. (I chose
Academic Search Premier.) |
Scroll down: the database suggests subject headings/controlled vocabulary to the right of
your results list!
Note: The location of lists of subject headings/controlled vocabulary does vary from
database to database. Explore the results page and article links; often there will be a list
included somewhere. |
Need some additional help with your research?
Don't hesitate to
Contact Us or
Make an Appointment if you need assistance.
Last revised: July 24, 2007
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