Japanese representation in leading general medicine and basic science journals: a comparison of two decades.

During 1991-2000, Japan contribution to the top general medicine journals was very small although the contribution to the top basic science journals was sizeable. However, it has not been examined whether the contribution to the top general medicine and basic science journals has changed during the last decade (2001-2010). The objective of this study was to compare Japan representation in high-impact general medicine and basic science journals between the years 1991-2000 and 2001-2010. We used PubMed database to examine the frequency of articles originated from Japan and published in 7 high-impact general medicine and 6 high-impact basic science journals. Several Boolean operators were used to connect name of the journal, year of publication and corresponding authors' affiliation in Japan. Compared to the 1991-2000 decade, Japan contribution to the top general medicine journals did not increase over the 2001-2010 period (0.66% vs. 0.74%, P = 0.255). However, compared to the same period, its contribution to the top basic science journals increased during 2001-2010 (2.51% vs. 3.60%, P < 0.001). Japan representation in basic science journals showed an upward trend over the 1991-2000 period (P < 0.001) but remained flat during 2001-2010 (P = 0.177). In contrast, the trend of Japan representation in general medicine journals remained flat both during 1991-2000 (P = 0.273) and 2001-2010 (P = 0.073). Overall, Japan contribution to the top general medicine journals has remained small and unchanged over the last two decades. However, top basic science journals had higher Japan representation during 2001-2010 compared to 1991-2000.