## 1 Introduction  
With the development of internet technology and the emergence of digital healthcare, healthcare service models are undergoing a profound transformation. Online Health Community (OHC) has become a critical platform for patients to acquire medical information and seek medical support [1]. In recent years, OHC has evolved beyond mere information dissemination channels, developing into a complex ecosystem that interconnects patients, physicians, and medical resources. However, despite OHCs playing an increasingly vital role in medical services, systematic research on their inner operational mechanisms and service quality evaluation remains insufficient. This research gap urgently necessitates an in-depth exploration of the structural characteristics and intrinsic logic of physicians' social networks within online health communities from multiple dimensions.  
Existing research predominantly focuses on surface-level characteristic analyses of OHCs, such as user interaction patterns [2; 3] and information transmission pathways [4; 5], but investigations into deep-level network structural characteristics and their influence on mechanisms on medical service quality remain relatively limited. Particularly, there is a lack of empirical research regarding the formation mechanism of the critical indicator of physician recommendation rates. This research gap not only impedes our comprehensive understanding of digital medical ecosystems but also constrains practical guidance for OHC service optimization. Recent research by [PERSON] et al. (2022) highlights the importance of understanding differences between patient and physician perceptions in healthcare settings, which further underscores the need to examine recommendation mechanisms in online health communities [6].  
In light of these considerations, this study aims to explore the network structural characteristics of OHCs and their impacts on medical services through the following research questions:  
1. What are the differences in the network's structural characteristics across different disease types of physicians? How do these differences reflect the functional division of labor and organizational logic within medical specialties?
2. What heterogeneous structural characteristics do physician groups of different professional titles (chief physicians/resident physicians) demonstrate within medical collaboration networks? What influences do these structural differences exert on medical service quality transmission?
3. What are the key factors that influence physician recommendation rates in online health communities? Specifically, how does post-consultation evaluation function as a core element of social trust negotiation within recommendation mechanisms?
4. How do network structural characteristics in digital medical ecosystems influence physician recommendation rates through social trust negotiation processes? What implications does this operational mechanism hold for platform management?  
This research will employ Social Network Analysis (SNA) methods combined with statistical analysis, using physician data from the \"Good Doctor Online\" platform to systematically analyze the network structural characteristics of OHCs and their influence mechanisms on medical service recommendation rates. Through this investigation, we hope to reveal the intrinsic structural logic of physician networks within OHCs and explain the multi-dimensional influence mechanisms of recommendation rates. By quantitatively analyzing the complex interactive relationships in online medical services, we aim to provide practical references for medical service quality enhancement and patient-physician trust construction, and offer novel theoretical support and practical guidance for constructing digital medical ecosystems.