Knowledge Base,Cognitive Proximity and Breakthrough Innovation——An Empirical Analysis Based on 7.72 Million Invention Patents
Through patent big data mining,the top 2%of patents cited per year were used to measure breakthrough innovation in 281 Chinese cities from 2000 to 2018.The fixed-effect model and panel quantile model were used to empirically examine the influence and interaction effects of knowledge base and cognitive proximity of regional cooperation on breakthrough innovation.The findings are as fol-lows.①Related variety is the main driving force of breakthrough innovation in Chinese cities,and technological breakthroughs mainly result from knowledge spillovers within related technological fields.②There is an inverted U-shaped relationship between unrelated vari-ety and breakthrough innovation,which plays an important role in high level cities,and with the increase of breakthrough threshold,the innovation effect of knowledge spillover among unrelated technological fields increases.③Cognitive proximity regulates the relation-ship between knowledge base and breakthrough innovation.When a city has an unrelated variety knowledge base,cross-regional knowl-edge cooperation with high cognitive proximity is conducive to technological breakthrough,but when a city has a highly related variety knowledge base,it is better to construct cross-regional knowledge cooperation relationships with higher cognitive distance.The research results provide theoretical support and empirical evidence for improving the city's breakthrough innovation ability and accelerating the re-alization of sci-tech self-reliance and self-strengthening at higher levels.