Here are some databases specifically suited to OH&S. Start with these to find more focused information then try multidisciplinary databases for more generalised resources.
The Physiotherapy Evidence Database (PEDro) contains randomised trials, clinical practice guidelines and systematic reviews in the field of physical therapy.
A large rigorous database, drawing peer-reviewed material from all disciplines. You can use the refinement options to narrow the research down to social work topics.
It is index-only, meaning you will need to select the 'Find Full Text' button to read full articles.