If you have a few key pieces of information such as the journal title (eg: Journal of Ecology), year, volume number and start page of an article, Citation Linker can lead you to the fulltext of the article. If you have the article's "doi" number, that is the only element you need to enter into Citation Linker.
In the field of biology, scientific journal articles are considered primary source material. Each research article describes the results of a scientific study or experiment.
Databases such as Biological Abstracts & Scopus gather together references to research articles. When you conduct a topic or keyword search on a database, you'll see a set of results, listing the titles of journal articles related to your topic.