I am wondering how can we rank the relevance of indexing databases (services) of academic journals. In particular I would like to see the top 5 to 10 scientific databases based on journal's importance. For example, the first place would be journals indexed in Current Contents. What database would be on the second place? On the 10th place? I am aware that a particular journal can be indexed in many databases. But are there any objective criteria that can help in answering this question?