The National Health Service Corps exists to increase the availability of primary care services to populations in Health Professional Shortage Areas (HPSAs). It aims to increase clinician availability by making loan repayments and awarding scholarships to individuals in exchange for their agreement to serve as clinicians (or providers) at approved sites. A report from the Congressional Research Service summarizes recruitment and retention programs, and funding trends from FY2010 through FY2017.
The report can be obtained at https://fas.org/sgp/crs/misc/R43920.pdf.