  The COVID-19 pandemic has sparked unprecedented mobilization of scientists,
generating a deluge of papers that makes it hard for researchers to keep track
and explore new directions. Search engines are designed for targeted queries,
not for discovery of connections across a corpus. In this paper, we present
SciSight, a system for exploratory search of COVID-19 research integrating two
key capabilities: first, exploring associations between biomedical facets
automatically extracted from papers (e.g., genes, drugs, diseases, patient
outcomes); second, combining textual and network information to search and
visualize groups of researchers and their ties. SciSight has so far served over
$15K$ users with over $42K$ page views and $13\%$ returns.
