You will find two types of research articles in peer-review science journals: primary and secondary.
Primary research articles describe original research written by the researcher(s) of the study. These include original research articles and case studies. For your Current Topics assignment you will need to find a primary research article on a surgery.
Review Arizona State University's Ask A Biologist website to learn more about how to identify an original research article by its components.
Secondary research provides a summary and/or analysis of original scientific research. The most common type of secondary research articles are review articles. These types of articles summarize a number of research studies in a particular area and provide analysis on the research as a whole. Review articles are not appropriate for your Current Topic Assignments.
Opinion pieces can also be published in scientific journals. The most common types of these articles that you will come across are editorials or perspective articles. While written by experts, these are subjective essays and are also not appropriate for your Current Topics assignment.