第二章：分析了名城开封的自然、社会环境的历史变迁以及开封形态的演变因素，指出了当今开封名城保护存在的问题。

Chapter two analyzes the city, s natural and social environment, s historical changes and the city, s structure, s transformation, and points out the present problems in the preservation of the city.

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目的：探讨在各个历史时期不同的碘环境下甲状腺功能亢进(甲亢)的演变趋向，总结其原发疾病及诊断治疗手段的变迁。

Objective: to discuss the evolution of hyperthyroidism under different iodine circumstances, and give a summary of transition, such as etiologic factor and methods of diagnosis and treatment.

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