8[2]GRILICHES Z.Productivity,R&D,and basic research at the firm level in the 1970's[J].American Economic Review,1986(1). 被引量：1
9[3]SCHERER.Firm size,market structure,opportunity and the output of patented inventious[J].American Economic Re-view,1965(5). 被引量：1
10[4]GRABOWSK H G.Industrial research and development,intangible capital stocks,and firm profit rates[J].Bell Journal of Economics,vol.9,No.2,autumn 1978,pp:328-43. 被引量：1
