So CORE (https://core.ac.uk/intro/api) apparently provides an API on top of >25 million ‘green’ open access deposits.
An R wrapper for this API might perhaps encourage more people to use and explore this aggregation, both for search and for text mining. It could form part of the
fulltext package, or given (perhaps preferably given the variability of quality and format of deposits) it’s own package.
If there already is an R wrapper for this, do let me know.