Primary sources are the first publications that report original research testing a research question or hypothesis. Some databases allow you to filter for primary sources or research articles. You can also search for the data sets that resulted from experiments.
Secondary sources use one or more primary sources to construct an argument about one or more tested hypotheses. They might use a data set from an experiment previously conducted to see if they get the same results.
Tertiary sources, such as systematic reviews, use primary and secondary sources, chosen according to a system, to give an overview of the state of research. Some databases allow you to filter results for review articles.
A scholarly article provides a summary of research into one aspect of a topic. There may be one author or several. Articles are shorteer than books. They usually take about a year to publish but pre-publication drafts may be made available within a year of concluding the research. Scholarly articles can be peer-reviewed for content: other scholars check that the methods of investigation were reasonable, the conclusions are supported by the data, and that the sources cited are current and credible. You must select "peer reviewed" when searching.
Search for articles using key words from your topic or question. Try using synonyms, and broader or narrower terms if needed. Search for articles in these databases:
Scholarly books provide a deep analysis of one topic. They are usually by one author, though an editor may group together chapters by different authors who are specialists within the topic. The introduction, preface, or forward to the book will provide an overview of the topic. Books take at least two years to publish, some even longer. Scholarly books are peer-reviewed for content: other scholars check that the methods of investigation were reasonable, the conclusions are supported by the data, and that the sources cited are current and credible.
Begin searching for books using broader terms like "genetics." Search for books in these databases:
Scholarly websites are usually portals for accessing articles and data sets. They may be maintained by libraries, universities, scholarly or professional societies and provide links to questions about research.
Data sets for experiments and trials supported by federal funding must be published. Many are available on the National Center for Biotechnology Information website.