Hosted research subset: check citations, catch fake/retracted papers, search OpenAlex & PubMed.
Free
One server, in research. Hosted research subset: check citations, catch fake/retracted papers, search OpenAlex & PubMed.
Research
Hosted research subset: check citations, catch fake/retracted papers, search OpenAlex & PubMed.
The rest either hold an API key issued by the publisher or ask for nothing.
Listed without a verification tick. Read the listing before installing.