[Research studies published in Assistenza infermieristica e ricerca from 1991 to 2011].

Objective: The research studies published on Assistenza Infermieristica e Ricerca along the last 21 years were analysed to identify main trends.
Method: Research articles were extracted and each was classified according to the main area, authors, place of origin, design.
Results: The number of research papers is progressively increasing and represents 50% of the papers published in 2006-2001. Most papers are focused on clinical practice and deal with issues relevant for the practice such as symptom control, organization or problems of elderly and frail populations. The number of experimental-quasi-experimental studies is limited (12%) but the variety of research designs increased in the last 5 years, with qualitative and validation studies.
Conclusions: Although the number good quality research papers is increasing, most studies are monocentric and research needs to be incremented and promoted.