求翻译：第二，坚持理论与实际相结合的原则。仅从理论上认识历史研究的方法是不够的，应从实践角度出发，切实运用几种研究方法解决几个实际问题。作为一门科学，历史学是十分严谨的，来不得半分虚构成分，只能依据历史材料，得出一些结论。但是历史研究的方法是多种多样的，尤其是国内外史学界在世界历史研究中，方法灵活、角度新颖、参考性强。如计量史学方法、反事实比较法和心理史方法等是近年来西方学者分析哲学和历史学常常采用的方法。这些方法不妨加以介绍和使用，这对于改变单一性思维模式，扩大知识视野具有重要作用。是什么意思？

正在翻译，请等待...

The first 2, adhere to the principle of combining theory with practice. Only from a theoretical understanding of history the methodology of the research is not enough, and should be from a practical point of view, and effectively use several research methods to solve several practical problems. As a

Second, uphold the principle of combining theory and practice. Only in theory is not enough to understand the methods of historical research, from the practical point of view, proper research on the application of several methods to resolve several practical problems. As a science, and history is ve