五、1990-2001年與2002-2007年作者研究主題趨於分散。 This study aims at using co-citation analysis of bibliometrics, and regards randomized controlled trials medical literatures as the research object to analyze the relevance between and between authors, in the hope of grasping the major areas, cluster of journals and authors of evidence-bases medicine through journal co-citation and author co-citation. This research takes randomized controlled trials medical literatures from 1990 to 2007 as research range. Data from 1990 to 2001 are taken from“A Bibliometrics Study on the Medical Literature of Randomized Controlled Trials”written by Yang Yen-Hsu in 2003. Data from 2002 to 2007 are retrieved from database of Medline. Then it combines the bibliometrics results of these two periods to acquired 48 core journals and 41 highly productive authors of randomized controlled trials from 1990-2007 as the samples of this study. Secondly, it compares the co-citation times between 48 core journals and 41 highly productive authors with Dialog to build co-citation matrix, and that result let us understanding the co-citation strength of periodicals and authors. We also use the SPSS software in the analysis of the co-efficient co-rrelation, multidimensional scaling analysis and cluster analysis between journals and authors.
The results of the study reveal that:
1.On the co-citation strength: (1).Co-citation frequency of randomized controlled trials journals are commonly high in the number of times. (2).Co-citation frequency of randomized controlled trials authors are too low in the number of times.
2.On the co-efficient co-rrelation analysis: (1).Co-efficient co-rrelation between journals are generally high, especially in anesthesiology, cardiovascular disease and internal medicine. (2).About 96% of author''s co-efficient co-rrelation shows negative co-rrelations. It indicates that there are great differences between the author’s research fields.
3.On the cluster analysis and multidimensional scaling analysis: (1).Periodicals of internal medicine and its branch fields have a stronger link than other medical fields. They are main disciplines in randomized controlled trials area. (2).We can''t judge the nuclear authors of evidence-bases medicine field
4.The main topic of 1990-2001 and 2002-2007 in periodical literatures is anesthesiology.
5.The author''s research fields of 1990-2001 and 2002-2007 are too divergent to find the core research subject.