Biological information exists in different formats including: articles, books, and data. Sources can be primary, secondary, or tertiary. Authors of primary sources analyze data. Secondary and tertiary sources interpret and summarize other sources. Primary sources are often the most up-to-date, but can be difficult to read and understand. Secondary and tertiary sources are often easier to understand, but have undergone additional interpretation.
Original research, evidence, and analysis
Examples: Research articles, Patents, Research data, Lab notes, Conference papers, Clinical trials
Search tip: Did the authors themselves collect or analyze data? If the answer is yes, it is probably primary research.
Summaries, evaluations, or interpretations of others' original research
Examples: Review articles, Book reviews, Annotated bibliographies
Search tip: Scholarly review articles are usually easier to understand than the primary literature. Try adding the term "review" to your search strategy to find them.
Collections and summaries of primary and secondary sources
Examples: Reference books, Dictionaries, Encyclopedias
Search tip: Try searching by the "Registry Number" to pull up properties in chemical databases.
How to Identify a Research Article:
Research articles are primary sources. The authors' of the article have conducted an original analysis of primary data (data they collected) or secondary data (data someone else collected). Research articles have section labels that are similar to a lab report such as: Introduction, Methods, Results, Discussion, and Conclusion. Research articles often include some data in the form of tables or some representation of data in the form of charts, graphs, or other visualizations. Here is an example of a research article:
How to Identify a Review Article:
Review articles are secondary sources. They summarize or reorganize information that was published in other articles. They often have section labels that are more specific to the topic. Here is an example of a review article:
|" "||"breast cancer"||Searches the exact phrase found in the quotes. This search will yield articles with "breast cancer," but NOT articles that only contain the word "breast," or the word "cancer," or contain the words separately.|
Signifies a wild card. Will yield articles with the prefix submitted and any ending, such as:
|AND||(cats) AND (dogs)||Adds search terms to the search, will limit the results to only articles that contain both terms. AND is usually implied, but can be used with parentheses and OR to make the search more precise.|
|OR||(Arabidopsis OR "A. thaliana")||Expands the search, a good way to add synonyms or binomial names to search terms. This example will return any article with either the word "Arabidopsis" or A. thaliana.|
|NOT||Ash NOT tree||Excludes articles that have the term. This will return results with the word "ash" but not if the results also contain the word "tree."|