This is the second option in the New Analysis screen of iCite:
Upload a spreadsheet of PubMed IDs (PMIDs) in the first column. File can be in .txt, .csv, .xlsx, or .xlsx format.
A maximum of 50,000 PMIDs may be queried at a time. Only the first 50,000 will be submitted to iCite.
Finally, click "Process" to proceed to the next page.
If more IDs are uploaded, you will receive an error message, although results will still populate: