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异质性竞争环境下买方势力对中国制药业创新投入影响的实证研究 被引量:2
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作者 丁正良 于冠一 李凯 《产经评论》 CSSCI 北大核心 2022年第3期5-21,共17页
在深入实施创新驱动发展战略的背景下,加速推进我国制药企业技术创新,既能为制药企业高质量发展提供强劲引擎,又能为维护公共卫生安全提供重要保障。结合Wind数据库和中财网数据库2014—2020年中国医药制造业上市公司数据,运用面板Tobi... 在深入实施创新驱动发展战略的背景下,加速推进我国制药企业技术创新,既能为制药企业高质量发展提供强劲引擎,又能为维护公共卫生安全提供重要保障。结合Wind数据库和中财网数据库2014—2020年中国医药制造业上市公司数据,运用面板Tobit模型,实证分析来自下游客户的买方势力对制药企业创新投入的影响。并依据产品类别、所处地城、所有权性质和规模对制药企业样本进行分组,以探讨异质性竞争环境下买方势力对供应商创新投入的影响机制。结果表明:(1)买方势力抑制制药企业的创新投入。(2)当卖方抗衡势力以市场份额衡量时,与创新投入正相关,支持熊彼特假说。(3)将卖方抗衡势力作为调节变量时,上游制药企业的抗衡势力存在显著差异,仅一类制药企业的抗衡势力能够显著改善买方势力对自身创新投入的负向影响,削弱买方势力的负效应;另一类制药企业不能依靠横向市场势力抗衡来自下游的买方势力,下游客户在市场交易中的抑制效应仍占主导地位,企业横向市场地位难以发挥正向调节作用。 展开更多
关键词 异质性竞争环境 买方势力 卖方抗衡势力 制药业 创新投入
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Importance of starting points in heterogeneous environments: interactions between two clonal plants with contrasting spatial architectures 被引量:3
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作者 Wei Xue Lin Huang Fei-Hai Yu 《Journal of Plant Ecology》 SCIE CSCD 2020年第3期323-330,共8页
Aims Plants can benefit from heterogeneous environments via disproportionately increasing resource harvesting in resource-rich patches.Their initial growing positions with respect to resource patches may thus have imp... Aims Plants can benefit from heterogeneous environments via disproportionately increasing resource harvesting in resource-rich patches.Their initial growing positions with respect to resource patches may thus have important influences on their performance and relative competitive ability.Such impacts may differ between species with contrasting spatial architectures.However,the potential influence of initial growing positions in heterogeneous environment on plant growth and competition has largely been ignored.Methods We grew the phalanx plant Carex neurocarpa and the guerrilla plant Bolboschoenus planiculmis alone or in competition in a heterogeneous environment consisting of high-and low-nutrient soil patches.In treatments without competition,one ramet of each species was grown in either a high-or a low-nutrient patch in the heterogeneous environment.In treatments with competition,a ramet of the target species was grown in either a high-or a low-nutrient patch,and a ramet of the competitor species was grown in the same patch as the target species or an adjacent patch with a different nutrient level.Important Findings Without competition C.neurocarpa produced more biomass and ramets when initially grown in a high-nutrient patch than when initially grown in a low-nutrient patch.With competition,these differences disappeared.Consequently,competitive intensity on C.neurocarpa was higher when it initially grew in a high-nutrient patch than when it initially grew in a low-nutrient patch.These impacts were independent of the initial position of its competitor.By contrast,the initial positions of B.planiculmis did not influence its growth or competitive response.Therefore,in heterogeneous environments,initial growing positions of clonal plants may influence their performance in competition-free environments and may also affect their relative competitive ability,and these effects may depend on spatial architecture of the plants. 展开更多
关键词 clonal plant COMPETITION environmental heterogeneity guerrilla patchy environment PHALANX
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