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Literature Searching

Need to find literature for your research, but don't know where to start? This guide is here to help!

What is a database?

The short answer: A collection of information organized so that it is searchable and retrievable.

Academic databases (such as PubMed, Scopus, and Web of Science) collect information about journal articles, book chapters, conference proceedings, dissertations, and much more in a particular area of scholarship. This information is then made to be easily searchable by you, the user.

Think of library databases as buckets and each bucket is filled with journals.  Looking in multiple buckets offers more journal coverage. No single bucket will have all the information you need.

The library subscribes to databases that provide coverage in areas relevant to the health sciences. No single database will hold all of the information needed for research, so it's important to search in more than one.

What does Indexing mean?

Journal articles and other material in databases are indexed with subject terms which makes them searchable.  Think of hashtags and social media.  When a hashtag is used it connects all photos or posts with that same hashtag.  Articles within databases have indexing terms attached to them connecting articles with similar themes. Once that term is input in a search bar it will bring up articles with the same or similar indexing terms.

Together, databases and indexing make finding scholarly articles possible.

For instance, Medical Subject Headings (MeSH) in PubMed are an example of indexing terms.


Boolean Operators

Boolean operators are used to pull search terms together. They allow you to connect key terms in a format that is searchable in a database.  The most common Boolean Operators are AND, OR, and NOT.


AND will narrow the search. It requires all terms connected by AND to be included in the search results. The example below reflects a search that requires both "diabetes AND nutrition" to be in the results.

Boolean AND Operator


OR will expand the search. It allows for either term to be present in the search results. It is used for connecting synonyms of search topic key terms. The example below reflects a search that requires either "medication OR prescription" to be included in the results. It does not require both.

Boolean OR Operator


NOT is used to exclude terms from the search. Use caution when using NOT, as it may weed out items are relevant to the topic. The example below reflects a search that includes smoking cessation but does not include any articles that also talk about pregnancy.

Boolean NOT Operator


Connecting Boolean Operators Together

Sometimes, when you have a complicated research question, using multiple Boolean Operators in one search string can be helpful. In these instances, connecting different parts of the search string together using parentheses will help (it will resemble a simple math equation). Let's connect the first two examples above:

Example: (diabetes AND nutrition) AND (medication OR prescription)

In this example, the system will first look for articles containing "diabetes AND nutrition." It will then look through the results for articles that contain "medication OR prescription." So, we will only get results that have to do with medication as it relates to the nutrition of diabetic patients.

If we did not use parentheses, our search string would look like this:

Incorrect Example: diabetes AND nutrition AND medication OR prescription

Do you see the difference? In the incorrect example, the system will look for articles that contain "diabetes AND nutrition AND medication," as well as ALL the entries in the database that contain "prescription," whether or not they have anything to do with the first part of the search.


Quotation Marks

There may be instances when searching which require results with a very specific term or phrase. When looking for an exact phrase or word, placing quotation marks on either side will prompt the database to search for the words in exactly the order they appear.

For example: "food desert"

By placing quotation marks on either side the database knows to look for those terms together, not separately in the article.


Database Filters

Most databases will have filtering options built in to the search page that can help narrow down your search results.  Options for filters can range from:

Date, Language, Age, Article Type, Location, etc.

Each database will present different options, but they can really help refine your search and make it more specific. (Think filtering by size or color when online shopping). Here is an example of filters in Web of Science, a popular database available on the Lewis Library web page: