My guess is that Science Direct is fully covered by Scopus, at least in theory. I'd also recommend you explore new generations of sources such as Dimensions and Lens, which are all supported by CiteSpace.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Dear professor Chen,
I was wondering if there is a way to use the Science Direct data on CiteSpace, cause, for my search, that database has a better roll of results.
Thank you.
My guess is that Science Direct is fully covered by Scopus, at least in theory. I'd also recommend you explore new generations of sources such as Dimensions and Lens, which are all supported by CiteSpace.