You can analyze the number of published articles with a certain keyword in Scopus https://www.scopus.com/. But selecting only cited articles is not an easy task.

Scopus is convenient, but the "official" impact factors which journals put on the homepages are calculated by Clarivate / Web of Science https://www.webofscience.com which also provides bibliometric data.

I would use Scopus, web of science or Google Scholar.

1) Select key words (carefully)

2) Arrange results according to the number of citations.

3) Find the last page where citation number changes from 1 to 0.

4) Multiply the selected nr of publications on the page on the number of pages.

Scholar works faster, text search is better, and it finds more citations. But it is less "official".