Abstract: Knowledge is not only an endogenous variable, but also an exogenous variable, which is the base to understand the characteristic of the increasing or decreasing return of hi-tochnology in knowlodgc-bascd cconomy.

• 文摘:知识既是内生变量，又是外生变量，这是理解高科技知识报酬递增与递减特点的基础。