[A historical and conceptual model for Primary Health Care: challenges for the organization of primary care and the Family Health Strategy in large Brazilian cities].

This paper focuses on the experience with Primary Health Care as a strategy for reorganizing the health care model, based on reforms in this direction and their implementation in the Brazilian case. The article identifies a shift in the discourse concerning health sector reforms, with a return to emphasis on primary care and integration of services. The Brazilian context demands reflection on the possibilities for synergy between this strategy and other social policies and the factors needed to ensure adequate performance. Evaluation research has suggested that primary care activities are slightly superior as compared to traditional health care units, despite persistent difficulties in access, physical infrastructure, team formation, management, and organization of the network. These difficulties correlate with a low level of public financing, persistent segmentation of the system, and weak integration of primary care services with other levels of care. From the technical perspective, a reasonable target is to guarantee the strategy's continuity with the necessary adjustments, conditioned by the dynamics of the health care technical models involved in the dispute.