Vizient Nurse Residency Resources: Building A Search

Databases can be multidisciplinary or subject specific. Choose the best databases for your research question.  A list of popular databases is provided below. You can access UNC Libraries' full listing of databases on the HSL website (arranged alphabetically or by subject).

Generally speaking, when literature searching, you are not searching the full-text article. Instead, you are searching certain citation data fields, like title, abstract, keyword, controlled vocabulary terms, and more. When developing a literature search, a good place to start is to identify searchable concepts of the research question, and then expand by adding other terms to describe those concepts. Read below for more information and examples on how to develop a literature search, as well as find tips and trips for developing more comprehensive searches.

Identify search concepts and terms for each

Start by identifying the main concepts of your research question. If unsure, try using a question framework to help identify the main, searchable concepts. PICO is one example of a question framework, and is used specifically for clinical questions. If your research question doesn't fit into the PICO model well, view other examples of question frameworks and try another!

Controlled Vocabulary

Controlled vocabulary is a set of terminology assigned to citations to describe the content of each article. Many databases assign controlled vocabulary terms to citations, but their naming schema is often specific to each database. For example, the controlled vocabulary system searchable via PubMed is MeSH, or Medical Subject Headings. More information on searching MeSH can be found here.

Note: Controlled vocabulary may be outdated and some database allow users to submit requests to update terminology.

Keyword Terms

Searching with controlled vocabulary can improve the relevancy of search results. Not all citations are indexed with controlled vocabulary terms, however, so it is important to combine controlled vocabulary searches with keyword, or text word searches. 

Authors often write about the same topic in varied ways and it is important add these terms to your search in order to capture most of the literature. For example, consider these elements when developing a list of keyword terms for each concept.

• Terms with similar meaning
  • flu
  • influenza
• Terms that have different spelling
  • American versus British spelling
  • hyphenated terms
• Acronyms
• Concepts described inconsistently
  • quality of life
  • satisfaction
• Broad versus specific terms
  • vaccination
  • influenza vaccination

There are several resources to consider when searching for synonyms. Scanning the search results of preliminary searches may help you identify additional search terms. Wikipedia, or other encyclopedias, may be helpful when looking for additional terms. Other databases can also help you identify synonyms. For example, PubChem can be used to look up drugs to find additional names and chemical compounds.

Combining controlled vocabulary and text words in PubMed would look like this:

"Influenza Vaccines"[Mesh] OR "influenza vaccine" OR "influenza vaccines" OR "flu vaccine" OR "flu vaccines" OR "influenza virus vaccine" OR "influenza virus vaccines"

Nesting

Nesting is a term that describes organizing search terms inside parentheses. This is important because, just like their function in math, commands inside a set of parentheses occur first. Parentheses let the database know in which order terms should be combined. 

Always combine terms for a single concept inside a parentheses set. For example:

Boolean operators

Boolean operators are used to combine terms in literature searches. Searches are typically organized using the Boolean operators OR or AND. OR is used to combine search terms for the same concept (ie, influenza vaccine). AND is used to combine different concepts (ie, influenza vaccine AND patients over 65 AND pneumonia). An example of how Boolean operators can affect search retrieval is shown below. Using AND to combine the three concepts will only retrieve results where all are present. Using OR to combine the concepts will retrieve results that use all separately or together. It is important to note that, generally speaking, when you are performing a literature search you are only searching the title, abstract, keywords and other citation data. You are not searching the full-text of the articles.

Field tags

The last major element to consider when building systematic literature searches are field tags. Field tags tell the database exactly where to search. For example, you can use a field tag to tell a database to search for a term in just the title, the title and abstract, and more. Just like with controlled vocabulary, field tag commands are different for every database.

If you do not manually apply field tags to your search, most databases will automatically search in set of citation data points. Databases may also overwrite your search with algorithms if you do not apply field tags. For systematic review searching, best practice is to apply field tags to each term for reproducibility.

For example:

("Influenza Vaccines"[Mesh] OR "influenza vaccine"[tw] OR "influenza vaccines"[tw] OR "flu vaccine"[tw] OR "flu vaccines"[tw] OR "influenza virus vaccine"[tw] OR "influenza virus vaccines"[tw] OR ((flu[tw] OR influenza[tw]) AND (vaccine[tw] OR vaccines[tw] OR vaccination[tw] OR immunization[tw])))

For more information about how to use a variety of databases, check out our guides on searching.

Combining search elements together

narrative about booleans and parenthesis

Translating search strategies to other databases

Databases often use their own set of terminology and syntax. When searching multiple databases, you need to adjust the search slightly to retrieve comparable results. Resources to help with this process are listed below.