Scinapse

What is Scinapse?
Scinapse is a free search engine for academic papers. As of April 2019, it indexes more than 200 million articles from more than 40,000 journals. It has more than 300,000 visitors on a monthly basis, as of April 2019.

Scinapse currently runs on a database collected from four major sources, namely Microsoft Academic Graph (MAG), Semantic Scholar Open Research Corpus (ORC), Springer Nature SciGraph, and PubMed. Refer to each source to investigate what they cover. Scinapse does not cover anything else.

https://scinapse.io/