Introduction to Literature Search

Keywords 

• natural language terms used to describe your topic
• can be combined a number of ways
• used when no appropriate subject heading exists
• sometimes too broad or too narrow

When searching, keywords can be used to...

• Search for singular and plural terms together
• Search for terms with different spellings
• Search for synonyms of terms together
• Search for phrases inside of quotation marks

Subject Headings

• also known as "controlled vocabulary"
• used by an organization to describe the concepts in the literature collected by that organization
• consistent in their definition across the records in the organization's database
• less flexible than keywords -- need to know the exact term to use (some databases have 'entry terms' that will connect the subject heading to term you've entered)
• a method to yield results very relevant to your topic

Databases that use subject headings

• PubMed -- called MeSH terms (Medical Subject Headings). Learn more about MeSH terms and how to use them here: The Basics of Medical Subject Headings (MeSH) in MEDLINE/PubMed: A Tutorial
• CINAHL -- called CINAHL terms. Learn more about finding and using these terms here: Using CINAHL/MeSH Headings

Boolean Operators

	Use to COMBINE TOGETHER separate topics.  Narrows your search Finds results that include ALL of your terms Examples: Cat AND Dog Exercise AND Heart Attacks
	Use tto CONNECT SYNONYMS or related ideas Broadens your search Finds results that include ANY of your terms Examples:  (Cat OR Dog) (Exercise OR Workout OR Aerobics)
	Use to REMOVE TERMS from the search results Narrows your search Further defines your term -- good for terms that might have multiple meanings Examples: Cat NOT Dog Nursing NOT breastfeeding

Phrase Searching

• Also known as quotation searching 
• Uses quotes " " to search for an exact phrase
• Useful when paired with OR
• The quotations "lock" in your terms and tell the database to retrieve results that have your terms appear exactly as they do in the quotations

A search for attention deficit disorder = attention AND deficit AND disorder  -- without phrase searching

A search for "attention deficit disorder" = "attention deficit disorder" -- with phrase searching

Truncation

• Uses a symbol to search for all possible forms of a word
  • Frequently used symbols include asterisk (*), a question mark (?), or a dollar sign ($)
• Broadens your search
• Useful to find alternate endings or plural form of a word
• Different databases use different symbols. Check the database's 'Help' or 'Search tips' pages for details on which symbol to use

Example: Child* = child, child's, childhood, children, children's, 

Note: The placement of the truncation symbol can impact the type of results you get back.

Example: If I searched Hum* with the expectation of getting versions of 'Human', I'd also get.... 

• Humans
• Humanoid
• Humorous
• Humor
• Hummus

Wildcards

• Use symbols to represent a letter or letters in a word
• Broadens your search
• Useful when searching with words that have different spellings
• Frequently used wildcard symbols include question marks (?), the pound symbol (#), or the astrisk (*)
• Different databases use different symbols. Check the database's 'Help' or 'Search tips' pages for details on which symbol to use

Examples:

• wom#n = woman or women
• col?r = color or colour

Medical Subject Headings (MeSH) in PubMed

Step 1: Locate and Search for Terms in the MeSH Database

The easiest way to access the MeSH database is by using the link on PubMed's homepage, located right under the Explore icon.

Search for one term at a time. Although the MeSH database is extensive, it is important to note that not every term is going to have a corresponding MeSH term.

Results will be displayed with brief definitions, ranked by relevance. Select the entry that best fits your needs to view the full record page. If there is only one result available, you will be brought directly into the record

Step 2: Review the MeSH Record

At the top of the MeSH recored page, you will see the term's definition and a list of subheadings. Scroll down to view Entry Terms (if available) and the MeSH Hierarchy.

• Entry Terms: terms that, when used to search in the MeSH database, will "map" to the current MeSH term
• MeSH Hierarchy: displays a hierarchy tree and where your term falls within it. The MeSH Hierarchy is very helpful for those who may not be familiar with their topic. The hierarchy shows the term in a variety of contexts

Step 3: Refine your Search with the MeSH Record

There are three possible options for refining your search with the MeSH record:

• Apply one or more subheadings: Adding subheadings to a MeSH term allows you to focus your search to those specific topics. If you do not apply any subheadings, PubMed will include all of them when it searches for your MeSH term
• Restrict to MeSH Major Topic: This will retrieve only citations where your subject is one of the main topics featured in an article
• Choosing the option "Do not include MeSH terms found below this term in the MeSH hierarchy: Only do this if you do not want PubMed to search for the narrower terms that appear beneath your MeSH term in the MeSH hierarchy

Step 4: Search for your MeSH Terms in PubMed

When you are ready, click the "Add to Search Builder" button located right under the PubMed Search Builder box, found on the right side of the screen. If you are using any subheadings, be sure to check their boxes  prior to select "Add to Search Builder". 
If you are ready to search for your MeSH term in PubMed, select the Search PubMed.