Doctor of Nursing Practice (DNP): A Guide to McFarlin Library Resources

Systematic literature search requires you to organise and tackle the search process in a structured and preplanned manner. It demands careful consideration of your search terms, selection of databases, choice of search methods, and requires you to reflect on the search results obtained during the process.

With a systematic literature search, you have a greater chance of avoiding disparities and bias, and it enables you to identify gaps in the existing research. In this way you also minimise the risk of reproducing already existing research.

It is important that you document your searches during the process so that your searches are, in principle, reproducible.

Source: Aarhus University Library

Within some fields there is an increasing tendency towards literature searches being required to be carried out as systematic reviews. There are specific requirements for a systematic review, and it is often a very time-consuming task. The following definition outlines the scope of a systematic review:

“A systematic review is a structured and pre-planned synthesis of original studies involving predefined research question, inclusion criteria, search methods, selection procedure, quality assessment, data extraction, and data analysis. No original study should deliberately be excluded without explanation, and the results from each study should justify the conclusion."

Source: Lund and Christensen (2016)

For a systematic review, it is important to broaden your search to maximize the retrieval of relevant results.

Use keywords:  How other people might describe a topic?

Identify the appropriate index terms (subject headings) for your topic.

• Index terms differ by database (MeSH, or Medical Subject Headings, Emtree terms, Subject headings) are assigned by experts based on the article's content.
• Check the indexing of sentinel articles (3-6 articles that are fundamental to your topic).  Sentinel articles can also be used to  test your search results.

Include spelling variations (e.g., behavior, behaviour). 

Source: University of Michigan Library

Boolean Operators (Using AND, OR NOT)

There are three basic Boolean search commands: AND, OR and NOT.

• AND searches find all of the search terms, limiting the results.
  • Example: (diabetes AND children AND processed foods) returns only results that contain all three search terms.
• OR searches find either one term or the other, expanding the results.
  • Example: (diabetes OR children OR processed foods) returns all items that contain any of the three search terms.
• NOT eliminates items that contain the specified term. 
  • Example: searching (diabetes NOT obesity) returns items that are about diabetes, but will specifically NOT return items that contain the word obesity. 

Using Boolean Search with Exact Phrases

If you're searching for a phrase rather than just a single word, you can group the words together with quotation marks. Searching on "childhood diabetes" will return only items with that exact phrase.  

A typical database search limit allows you to narrow results so that you retrieve articles that are most relevant to your research question. Limit types vary by database & include:

• Article/publication type
• Publication dates
• Species
• Language
• Sex
• Subject
• Ages

In a systematic review search, you should use care when applying limits, as you may lose articles inadvertently.

Source: University of Michigan Library

PubMed offers a wide range of online trainings aimed at the novice as well as the experienced researcher. 

To see a full list of their trainings visit their online training hub.

Suggested trainings: 

• PubMed: Find articles on a topic 
• PubMed Subject Search: How It Works 
• PubMed: Using the Advanced Search Builder