求翻译：行星齿轮传动在我国已有了许多年的发展史，很早就有了应用。然而，自20世纪60年代以来，我国才开始对行星齿轮传动进行了较深入、系统的研究和试制工作。无论是在设计理论方面，还是在试制和应用实践方面，均取得了较大的成就,并获得了许多的研究成果。近20多年来，尤其是我国改革开放以来，随着我国科学技术水平的进步和发展，我国已从世界上许多工业发达国家引进了大量先进的机械设备和技术，经过我国机械科技人员不断积极的吸收和消化，与时俱进，开拓创新地努力奋进，使我国的行星传动技术有了迅速的发展。是什么意思？

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The planetary transmission had many years history in our country, very early had the application.However, since the 20th century 60's, our country only then has started to the planetary transmission to conduct thorough, the system research and the experimental work.Regardless of is in the design the

Planetary gear drive in our country has had a history of many years, has for a long time. However, since in the 1960 of the 20th century, planetary gear transmission began to be more in-depth and systematic research and development work. Both in terms of design theory, and also in terms of preparati