Research - also known as primary, scholarly or empirical articles (example: PMID 23202818)
Empirical studies use data derived from observation or experiment. Original research papers (also called primary research articles) that describe empirical studies and their results are published in peer-reviewed academic journals. Articles that report empirical research usually contain different sections which relate to the steps of the scientific method.
Abstract - The abstract provides a very brief summary of the research.
Introduction - The introduction sets the research in a context, providing a review of established and related research and develops the hypotheses for the research.
Methods - The methods section describes how the research was conducted.
Results - The results section describes the outcomes of the study.
Discussion - The discussion section contains the interpretations and implications of the study.
Works Cited (aka References aka Bibliography) - This section lists the articles, books, and other material cited in the paper.
Primary
What is it? Original research, based on observation/experience.
Examples: Results of studies (such as Randomized Controlled Trials, Qualitative Studies) with methodologies, data, results, and conclusions.
Where to find it: Published in peer-reviewed journals such as NEJM, Critical Care Nurse, JAMA, Journal of Advanced Nursing, (found in databases like PubMed & Embase). Dissertations. Conference abstracts or proceedings.
Secondary
What is it? Secondary articles summarize and appraise multiple relevant primary studies to answer a clinical question. Also called filtered, pre-appraised, or synthesized.
Examples: Review articles, systematic reviews, meta-analysis, Best Practice Guidelines.
Where to find it: Cochrane Library, TRIP database. Filters in databases like PubMed, Embase for systematic reviews/meta-analyses in databases. Scholarly books (monographs).
Tertiary
What is it? An overview of primary and secondary sources such as textbooks or handbooks. A background/introduction to principles and practices within the discipline.
Examples: “Harrison's Principles of Internal Medicine.” “Watson's Clinical Nursing & Related Sciences.”
Where to find it: Textbooks, review articles.
"Gray"
What is it? Literature not readily available through conventional academic sources, also known as ‘hard to find.’ Usually not indexed or published in a peer-reviewed journal.
Examples: Proceedings from the 25th Conference on Retroviruses & Opportunistic Infections.
Where to find it: Data sets, conference proceedings, clinical trial data, government reports, trade journals, statistics.