排序方式: 共有137条查询结果,搜索用时 31 毫秒
51.
通过观察白藜芦醇对淀粉样蛋白(Aβ25—35)诱导的空间学习记忆功能损伤的影响,探讨白藜芦醇对老年痴呆的治疗作用.方法是采用侧脑室注射Aβ25—35和腹腔注射白藜芦醇2周后进行Morris水迷宫测试.比较不同处理后的大鼠逃避潜伏期、到达平台游过距离以及目标象限内游泳所占的时间百分比.得到以下结果(1)Aβ25—35引起大鼠学习记忆的下降;(2)白藜芦醇有效地逆转Aβ25—35导致的学习记忆的损伤.因此,腹腔注射白藜芦醇有效地阻止了Aβ25—35对学习记忆的损伤.这些结果提示白藜芦醇是治疗AD学习记忆功能损伤的有效策略. 相似文献
52.
Using Lu's continuation theorem, the extension one of Manásevich-Mawhin, we study the existence of periodic solutions for p-Laplacian neutral Liénard equation of the form
(?p(x(t)-cx(t-σ))′)′+f(x(t))x′(t)+β(t)g(x(t-τ(t))=e(t). 相似文献
53.
Daeyong Lee 《Research Policy》2018,47(5):854-871
This article examines how the excise tax affects firms’ R&D investment, performance, and market strategy in the US medical device industry. The Affordable Care Act imposed a 2.3% excise tax on medical devices beginning in January 2013, and thus this study compares the medical device firms with other high-tech firms before and after the tax incidence. Using COMPUSTAT data from 2006 to 2015, the author finds that the excise tax reduced R&D investment, sales revenue, gross margins, and earnings for medical device firms. In addition, the excise tax increased their global market sales intensity, global market diversification, and customer diversification in the US domestic market. 相似文献
54.
We relate innovation to sales growth for incumbent firms in high-tech sectors. A firm, on average, experiences only modest growth and may grow for a number of reasons that may or may not be related to innovative activity. However, given that the returns to innovation are highly skewed and that growth rates distributions are heavy-tailed, it may be misleading to use regression techniques that focus on the ‘average effect for the average firm’. Using a quantile regression approach, we observe that innovation is of crucial importance for a handful of ‘superstar’ fast-growth firms. 相似文献
55.
R&D subsidies designed to encourage innovation efforts by firms may have intended and unintended effects on the way they organize their innovation process. We present empirical evidence on how R&D subsidies affect firms’ R&D cooperation strategies. In particular, we investigate whether receiving public R&D subsidies affect the probability that a firm will set up an R&D partnership with a public research organization (PRO), or with other firms. Our main findings are: (i) public support significantly increases the chances that a firm will cooperate with a PRO, and (ii) public support also increases the likelihood that a firm will establish private partnerships, but to a smaller extent and only when firms have intangible knowledge assets. These results suggest that public R&D programmes trigger a behavioural change in firms’ R&D partnerships, alleviating barriers to cooperation. 相似文献
56.
In this paper we study boundary value problems for anisotropic partial differential-operator equations with parameters. The principal part of the appropriate differential operators are not self-adjoint. Several conditions for the uniform separability in weighted Banach-valued Lp-spaces are given. Sharp estimates for the resolvent of the corresponding differential operator are obtained. In particular the positivity and R-positivity of these operators are established. As an application we study the separability of degenerate DOEs, maximal regularity for degenerate abstract parabolic problem with parameters, the uniform separability of finite and infinite systems for degenerate anisotropic partial differential equations with parameters. 相似文献
57.
第25届亚洲男篮锦标赛中、伊男篮攻防能力的对比分析 总被引:1,自引:1,他引:0
李贺林 《体育科技文献通报》2010,18(8):42-43
对第25届亚洲男篮锦标赛中、伊比赛的技术数据进行了统计,分析对比了中国队与上届冠军伊朗队在攻守两方面技、战术运用的情况,寻找与伊朗的差距。,力争对中国男篮今后的发展提出了对策和建议。 相似文献
58.
杜照军 《体育科技文献通报》2010,18(11):30-31
本文运用文献法、录像法和数理统计法,对第25届亚洲男篮锦标赛中国队对西亚的黎巴嫩、约旦和伊朗四场篮球比赛技术指标进行了统计和对比分析,得出中国男篮在各项指标全面落后于伊朗,在3分球和失误方面落后于黎巴嫩和约旦。 相似文献
59.
(n-C12H25NH3)2CuBr4可作为固-固相变贮热材料,利用Kissinger及Ozawa两种非等温动力学模型,处理了标题化合物的DSC实测曲线,计算了固-固相变过程中的表观活化能和反应级数。 相似文献
60.
Manfred Novak 《Zeitschrift für Hochschulrecht, Hochschulmanagement und Hochschulpolitik: zfhr》2007,6(1):18-25
Die bereits im Zuge der Autonomie-St?rkung der Universit?ten durch das UOG 1993 im Rahmen der Erlassung des UniStG 1997 vorgenommene
Aufwertung der Selbstregelungskompetenzen der Universit?ten bei der Gestaltung des Studienrechts, findet in der Fassung der
studienrechtlichen Vorgaben des UnivG 2002 seine konsequente Fortsetzung. Diese Ausweitung der Selbstregelungskompetenzen
geht im rechtsstaatlichen Sinne typischerweise (als Gegengewicht) mit besonderen Anforderungen an Rechtsschutz und Rechtssicherheit
einher. Insofern hat der universit?re Verordnungsgeber auch auf die in den Gesetzesgrundlagen zum Ausdruck kommenden Wertungen
und Grunds?tze eingehend Bedacht zu nehmen. 相似文献