PSE Health Energy
gathers all the scientific reports done in the US on fracking
In the Library section the studies are classified thematically.
In the specific section at ZOTERO you find a different approach to study citations held in the PSE database.
The Endocrine Disruption Exchange
Peer-reviewed Papers on Chemicals in Oil and Gas Operations
This database lists references to peer-reviewed scientific articles related to unconventional oil and gas production. Most references included on this page were chosen for their relevance to potential health impacts from exposure to oil and gas related chemicals.
Public Medline
is a searchable bibliography of millions of medical and some technical scientific publications.
Example search “hydraulic fracturing health”
by 
frack-free.rocks is a project that collects information on technical, political, scientific, social, legal and environmental aspects related to the mining technique called hydraulic fracturing, also known as "fracking".