Complex sentence: Libraries are charged an "institutional rate" that is far higher than that charged to an individual subscriber; most are academic libraries that are part of the same class of institutions that generate most of this research in the first place.
Split into simpler sentences: Libraries are charged an "institutional rate" that is far higher than that charged to an individual subscriber. Most of these libraries are academic libraries that are part of the same class of institutions that generate most of this research in the first place.