Although access to the material in PMC is free, the use of the material still is subject to the copyright and/or related license terms of the respective authors or publishers. See the PMC Copyright Notice for more information.You may NOT use any kind of automated process to download articles in bulk from the main PMC site. PMC will block the access of any user who is found to be violating this policy. However, there are a few article datasets within PMC where bulk retrieval of files for text mining and other purposes is permitted. License terms may vary by dataset or even within a dataset. To download a dataset in PMC, you must use a designated service, such as the PMC FTP service. See the full listing of APIs that you can use for accessing PMC data on the For Developers page.