[Literature of so-called "clinical research": structure and trends, 1991-2010]

The authors studied trends and patterns in the literature of research labeled as clinical (i.e., having the word "clinical" in their title) in the period between 1991 and 2010. The main findings are: 1. The growth of the literature under study was somewhat stronger than that of the overall medical literature. 2. The dominance of the USA is strong but is challenged by some of the most rapidly developing countries (particularly in the Far-East region: China, Korea) in total production, and by the developed European countries in highly cited publications. The eminence of Italy is remarkable. 3. In comparing the medical fields, the most striking tendencies are the increase of oncology and the attenuation of internal medicine. Surgery is steadily growing in size but decreasing in its citation influence. 4. Word frequency studies support the ever growing weight of oncology and also of genetics. 5. Beyond the thematic changes, word frequency studies also reveal a substantial change in attitude: in the period under study more and more effort was made on emphasizing the usefulness, efficiency and risks of the results in contrast with the more descriptive, investigative approach of the past. The role of therapy is growing, the role of diagnostics is decreasing. The knowledge of these trends and patterns may orient health and science policy makers to cope appropriately with the ever changing world of clinical research.