PubMed Central (PMC) raw data is hosted on the NCBI servers which provide convenient access using rsync.
Download PMC data using a rsync command like
rsync -Pav ftp.ncbi.nlm.nih.gov::pub/pmc/oa_bulk/\*.tar.gz PMC/
This example command will download all bulk data files as .tar.gz containing text files.
You can explore the PMC directory structure by accessing the NCBI FTP server using your browser.