There are a lot of sources out there, but these are some common academic sources that you're going to encounter, evaluate, and use often.
This is the most common type of journal manuscript used to publish full reports of data from research that was conducted by the authors of the article. It may be called an original research article, primary research article, empirical research, research, or even just an article, depending on the journal. The original research format is suitable for many different fields and different types of studies. It typically includes full Introduction, Methods, Results, and Discussion sections, sometimes in the abstract (seen below) as well as the article itself.
Systematic Review - A systematic review is conducted to answer specific, often narrow clinical questions. These questions are formulated according to the mnemonic PICO (Population, Intervention, Comparison, Outcomes). A systematic review involves the identification, selection, appraisal and synthesis of the best available evidence for clinical decision making. A properly conducted systematic review uses reproducible, preplanned strategies to reduce bias and instill rigor and pools of information from both published and unpublished sources. A quantitative systematic review uses staistical methods to combine results of multiple systems, and may or may not be a meta-analysis.
It is not unusual now to find more that one systematic review addressing the same or similar questions paving the way for meta-summary or meta-study, a systematic review of systematic review.
Meta-Analysis - a quantitative approach that permits the synthesis and integration of results from multiple individual studies focused on a specific research question. The outcome of this quantitative approach for reviewing literature has tremendous potential for a practice-based discipline such as nursing.
A case study is an investigation of a single subject or a single unit, which could be a small number of individuals who seem to be representative of a larger group or very different from it. The unit of analysis also could be families, organizations, institutions (colleges, factories, hospitals), programs, or events. It is the researchers' choice to focus on individual cases and neither the size of the bounded entity nor the methods used to conduct the investigation that defines this research approach.
A thesis is a lengthy scholarly work that is written as a requirement for obtaining a Master's degree; a dissertation is similar (though it will likely be longer and more in-depth than a thesis), but for a doctoral degree. There are designed to add original research or perspectives to the author's field of study, and are usually structured with the same sections as a scholarly article, but expanded. Theses and dissertations are great sources for exhaustive literature reviews, methodologies, data, references and other research tools to inform your own work.