The absorption of electromagnetic radiation of a specific frequency by an atomic nucleus that is placed in a strong magnetic field, used especially in spectroscopic studies of molecular structure and in medicine to measure rates of metabolism.核磁共振：位于一强烈磁场的原子核对特定频率的电磁反应吸收，常用于分子结构的分谱学研究和医学上测量新陈代谢速度