【作者(必填)】Samuel Kortum

【文题(必填)】Equilibrium R&D and the Patent--R&D Ratio: U.S. Evidence

【年份(必填)】1993

【全文链接或数据库名称(选填)】http://xueshu.baidu.com/s?wd=paperuri%3A%28373d422e1977a08cbbedddc7f8daadc7%29&filter=sc_long_sign&tn=SE_xueshusource_2kduw22v&sc_vurl=http%3A%2F%2Fwww.jstor.org%2Fstable%2F2117707&ie=utf-8&sc_us=11201208791944088214
急需文献一篇，求哪位能帮帮忙。谢谢！