Background: Over the last 10 years, the German Cochrane Centre (GCC) has participated in the global retrospective search (handsearching) of health care journals by covering journals published in the German-speaking regions (Switzerland, Austria, Germany). Though some of these journals are published in English, there are still many important scientific medical trials (randomised controlled trials, RCTs, and clinical controlled trials, CCTs) which are published in German. Moreover, many of the German-language journals are not included in electronic databases such as Medline. Without handsearching, these trials would not be electronically detectable and, thus, could not be used in systematic reviews.
A future prospective trial registration process could replace the need for handsearching. Planned trials would have to be registered in a central and public trials register and the data could be directly included without delay in the Cochrane Library's trials database. Even so, there remains the unfinished task of completing the handsearching of the still unread volumes and journals. To determine the expenditure of completing this task, the number of unread health care journals in the German-speaking area must be quantified (e.g. Ulrich's web).
Methods: The results of the GCC's handsearching since it began with a Europe-wide handsearching project in 1995 are shown, and a suggestion of the future needs for handsearching projects in Germany is given.
Results: During the GCC's involvement in the European handsearching project, 17,000 RCTs and CCTs were recorded.
Based on rough analyses, it can be estimated that, at the current rate of progress, another 10 years of handsearching will be needed to search the remaining journals and volumes. The number of the recorded trials will increase to about 34,000.
Discussion: To finish the handsearching activities, there is a lot of work to do. Even after 10 years, handsearching at the GCC still finds journals which are not included in Medline, but which contain a very large number of RCTs and CCTs (e.g. 'Deutsche Zeitschrift fur Sportmedizin'). Intensifying handsearching with stable funding would accelerate the project.