491. 汉语语法研究 Research on Chinese Grammar
492. 汉字信息处理技术 Technology of Chinese Information Processing
493. 毫微秒脉冲技术 Millimicrosecond Pusle Technique
494. 核动力技术 Nuclear Power Technology
495. 合唱与指挥 Chorus & Conduction
496. 合金钢 Alloy Steel
497. 宏观经济学 Macro-Economics
498. 宏微观经济学 Macro Micro Economics
499. 红外CCD Infrared CCD
500. 红外电荷耦合器 Infrared Electric Charge Coupler
