This paper investigates the consequences of institutional changes on academic research practices in eight fields of natural science in the Netherlands. The authors analyse the similarities and differences among the dynamics of these different fields and reflect on possible explanations for the changes observed. The study shows that the increasing pressure for productivity, as measured in bibliometric terms, can counteract the pressure for practical utility. Moreover, the work indicates that the dynamics of science varies much more across scientific fields than most of the literature suggests is the case. (Contains 9 notes, 2 figures and 6 tables.)