Institut for Medical Informatics, RWTH Aachen University, Pauwelsstrasse 30, 52057 Aachen, Germany.
Int J Med Inform. 2010 Apr;79(4):297-303. doi: 10.1016/j.ijmedinf.2010.01.007. Epub 2010 Feb 12.
In PubMed search forms, the publication date refers to both the date of electronic and printed publication. This fact is documented in PubMed, but difficult to anticipate by the users and can provoke misinterpretations of search results. The Technical Note aims at systematically investing the effect (referred to as the publication echo), clarifying onset and extent of the publication echo, and comments on its impact.
Papers with ambiguous publication dates are systematically retrieved and a trend analysis with seasonal decomposition on monthly publication data is performed.
First doubled search results were found for 1999, their number since then rapidly increasing. Up to 17.6% of all articles of a year are found to be published electronically and in print, which can be before or afterwards. Maximum delay between the two dates is three years, except for one singular publication, where it is five years. Publication trends are exponential and linear when considering echoed and echo-cleaned data, respectively.
As a conclusion, we suggest using a query formulation that unambiguously retrieves literature from PubMed by the date of publication.
在 PubMed 搜索表单中，出版日期既指电子出版物的日期，也指印刷出版物的日期。这一事实在 PubMed 中有记录，但用户很难预料到，并且可能会导致对搜索结果的误解。本技术说明旨在系统地研究这种影响（称为出版回声），阐明出版回声的开始和程度，并对其影响进行评论。
系统地检索具有模糊出版日期的论文，并对每月出版数据进行季节性分解的趋势分析。
1999 年首次发现了重复的搜索结果，此后其数量迅速增加。每年有多达 17.6%的文章以电子和印刷两种形式出版，这可以发生在之前或之后。这两个日期之间的最大延迟是三年，但有一个特殊的出版物是五年。分别考虑回声和清除回声的数据时，出版趋势是指数和线性的。
因此，我们建议使用一种查询公式，通过出版日期从 PubMed 中明确检索文献。
