Abstract: Objective To explore the changes of the internal structure and research topics of oncology from 2005 to 2014, and offer reference for the development of the related studies and research policies. Methods The articles published in 203 journals in the area of "oncology" from 2005 to 2014 included by JCR were chosen. Firstly, we cleaned the author keywords using the TDA software. After that, we standardized and categorized the keywords according to the Medical Subject Headings (MeSH) manually. In the end, we builted the cooccurrence matrixes of highfrequency words in three stages: 2005—2007, 2008—2010 and 2011—2014, and drew the evolution maps and strategic diagrams of each stage to analyze the changes of the internal structure and research topics of oncology. Results While the word frequence increasing rapidly, the main keywords reduced gradually from 2005 to 2014. The traditional treatments such as chemotherapy and radiotherapy, the diagnostic and the epidemiological investigation were the core subject of oncology. With the screening of neoplasms, the research on the cell physiological phenomena and the genetic phenomena gained vigorous expansion. "Breast neoplasms", the topic whose deep exploration also led the development of other topics, has always been the hard nut as well as the hot topic of the oncology. During this period, researches on the screening of neoplasms and the genetic phenomena were developed rapidly. Conclusion The content of oncology will be more thoroughly with some merge, division, development, declining and perishing of the internal themes occurred as well. The boundaries among the substructure are becoming more and more blurred and the screening of neoplasms and the genetic phenomena has gradually become the dominant trend in general practices.

Key words: Medical oncology, Cluster analysis, Medical subject headings, Co-word analysis, Cluster evolution map, Strategic diagram