research centers are among the most important institutes in a scientific society. using the altavista search engine and webometric methods, this research tries to find the performance and impact of the top research centers of the islamic world countries. the results reveal that from 57 countries, 40 of them did not have any research centers scored in webometric ranking and the rest of them had ...

efficiency calculations for units belonging to one group according to data envelopment analysis widely have received attention; while experiences related to efficiency comparison of several groups consisted of decision making units is restricted. kao's parallel system network dea model that has been designated aimed at such a comparison, practically leads to accomplish comparison among uni...