According to a paper uploaded to arXiv in April 2013, papers now need about twice as many citations to rank in the top 5% or 1% papers as they did 40 years ago. Since the late 1980s, a decreasing proportion of top cited papers have been published in elite journals. The study looked at citation patterns over the last 40 years of seven elite journals (including Science and Nature) and six “emerging” journals (including PLoS One, Nano Letters, Advanced Materials and Nature Materials). The authors conclude that “researchers now have the option to publish in more diverse venues knowing that their work can still reach the same audiences” and discuss the implications of their study for research evaluations.

Vincent Lariviere, George A. Lozano, Yves Gingras. Are elite journals declining?
arXiv:1304.6460v1 [cs.DL]