中文摘要：

本文将企业研发行为分为“是否研发”和“投入多少”两个阶段，就政府补贴对不同所有制企业研发决策的影响进行研究．理论方面，构建企业研发决策的两阶段模型，讨论了补贴对企业研发投资的作用机制．实证方面，以中国工业企业为对象，选择Heckman两步法和2SLS分别处理了样本选择性偏误及变量间的内生性问题，对来自国有、私营和外资企业的分类样本进行了检验，结果表明：在不同的所有权性质下，政府补贴对企业研发投资的作用存在一定差别，国有企业面对优惠政策的倾斜和需要担负的社会责任，从事技术创新活动的概率较高，但由于特殊的产权关系和预算软约束等原因，缺乏扩大研发投入的动力；对于治理机制完善的外资企业和处于市场竞争弱势地位的私营企业而言，政府补贴的研发激励效果更为明显．

英文摘要：

In this paper, the firm＇ s R＆D decision is separated into two stages： whether to invest and how much to invest. The influences of government subsidy on R＆D decisions in firms with different ownership structures are discussed. Theoretically, a two-stage model of firms＇ R＆D decisions is constructed to investi- gate the mechanism of subsidy on R＆D investment. Empirically, using the sample data of Chinese industrial firms, the Heckman two-step method and two-stage least square are used to deal with sample selective bias and endogeneity respectively. The sub-samples of state-owned, private and foreign firms are also tested separately. The results show that under different ownership structures, the influences of government subsidy on firms＇ R＆D decisions are different. To undertake social responsibility, the state-owned firms usually have a high probab lations ility of engaging in R＆D activities under preferential policies. However, because of special property re- and soft budget constraints, the state-owned firms lack incentives to increase R＆D investments. For the well-organized foreign firms and less competitive private firms, the incentive effects of government subsidy on R＆D are more obvious.