you can put them together and explain the different resource probably causes
different citiation number. And emphysize the more one.
for example:
The reasons for the difference in the number of results retrieved from
Scopus only and the total number retrieved from Google Scholar, Scopus, ISI
Web of Science and Chinese paper searcher (CNKI)( China National Knowledge
Infrastructure) combination are: I. Difference database sources. II. ISI Web
of Science, and Scopus focus on the most prestigious, high-impact research
journals, whereas Google Scholar broadly searches for scholarly literature.
III: Chinese paper searcher (CNKI) only includes the information of Chinese
paper.