The academic literature within natural and health sciences is published primarily in the form of articles published in scientific peer-reviewed journals. Other important sources can be doctoral theses, conference proceedings, patents, legislation, statistics.

Peer review means that the article is assessed for quality by experts (peer-reviewers) within the same field. On the basis of recommendations from the peer reviewers, the editor of the journal decides whether the article should be accepted for publication, revised or rejected.

Original research articles (primary sources)

There are several types, but the common thing is that they report on new knowledge within an often specific research topic and they must not have been published previously. They are written by experts for experts and are quality assessed by experts (peer review).

The most thorough, most detailed and elaborated are the so-called Original Research Articles, sometimes also for Research Article, Original Paper, Full Length Research Article or simply Article depending on the individual journal. They are structured in these sections according to IMRAD, which stands for:

introduction,
Method/Materials,
Results and
Discussion

Eksempel: Original research article

Review articles (secondary sources)

A review article summarizes, describes and evaluates the primary existing literature within a specific research field. Review articles do not in themselves present new primary research results. There are several types of review articles, but here are the two most important:

Systematic Reviews (SR) are the most comprehensive. They identify, summarize evidence, analyze and assess relevant research literature in relation to a clear, pre-defined research question and based on some very specific methods and criteria. They follow the IMRAD structure.

Scoping Reviews are less extensive and often a precursor to Systematic Reviews.

Examples: Systematic Review, Scoping Review