Open-Access Paper Full Text

Full text and open-access PDF retrieval for a paper. Given an arXiv id, DOI, OpenAlex id, PMID, or PMCID, returns the readable body split into sections (introduction, methods, results) plus the open-access PDF location: arXiv via ar5iv, biomedical via Europe PMC, OA locations via OpenAlex for the rest. The 'now read it' call after a paper search. Keyless.