首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   27133篇
  免费   888篇
  国内免费   165篇
管理学   1423篇
劳动科学   2篇
民族学   576篇
人才学   7篇
人口学   456篇
丛书文集   2794篇
理论方法论   1872篇
综合类   16579篇
社会学   2179篇
统计学   2298篇
  2024年   36篇
  2023年   159篇
  2022年   218篇
  2021年   291篇
  2020年   353篇
  2019年   542篇
  2018年   673篇
  2017年   1075篇
  2016年   543篇
  2015年   494篇
  2014年   1218篇
  2013年   1960篇
  2012年   1378篇
  2011年   1422篇
  2010年   1227篇
  2009年   1323篇
  2008年   1337篇
  2007年   1673篇
  2006年   1745篇
  2005年   1529篇
  2004年   1619篇
  2003年   1745篇
  2002年   1410篇
  2001年   1314篇
  2000年   732篇
  1999年   381篇
  1998年   163篇
  1997年   140篇
  1996年   159篇
  1995年   146篇
  1994年   126篇
  1993年   87篇
  1992年   85篇
  1991年   65篇
  1990年   49篇
  1989年   33篇
  1988年   36篇
  1987年   5篇
  1986年   5篇
  1985年   118篇
  1984年   113篇
  1983年   78篇
  1982年   80篇
  1981年   71篇
  1980年   69篇
  1979年   63篇
  1978年   57篇
  1977年   11篇
  1976年   17篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
From the economical viewpoint in reliability theory, this paper addresses a scheduling replacement problem for a single operating system which works at random times for multiple jobs. The system is subject to stochastic failure which results the imperfect maintenance activity based on some random failure mechanism: minimal repair due to type-I (repairable) failure, or corrective replacement due to type-II (non-repairable) failure. Three scheduling models for the system with multiple jobs are considered: a single work, N tandem works, and N parallel works. To control the deterioration process, the preventive replacement is planned to undergo at a scheduling time T or the job's completion time of for each model. The objective is to determine the optimal scheduling parameters (T* or N*) that minimizes the mean cost rate function in a finite time horizon for each model. A numerical example is provided to illustrate the proposed analytical model. Because the framework and analysis are general, the proposed models extend several existing results.  相似文献   
22.
23.
2018 marks the 50th anniversary of Enoch Powell’s infamous ‘Rivers of Blood’ speech, an intervention that is still viewed as one of the most incendiary statements of the perceived decay and violence likely to follow legislation intended to assure minoritised British citizens of equal rights regardless of their ethnic origin. In this essay, Sally Tomlinson (one of Britain’s foremost multicultural theorists) reflects on Powell’s legacy and the contemporary scene where in the US, UK and across Europe, White resentment and fear is increasingly shaping ‘mainstream’ debates about nationhood, migration and education.  相似文献   
24.
In this article, we introduce tempered Mittag-Leffler Lévy processes (TMLLP). TMLLP is represented as tempered stable subordinator delayed by a gamma process. Its probability density function and Lévy density are obtained in terms of infinite series and Mittag-Leffler function, respectively. Asymptotic forms of the tails and moments are given. A step-by-step procedure of the parameters estimation and simulation of sample paths is given. We also provide main results available for Mittag-Leffler Lévy processes (MLLP) and some extensions which are not available in a collective way in a single article. Our results generalize and complement the results available on Mittag-Leffler distribution and MLLP in several directions. Further, the asymptotic forms of the moments of the first-exit times of the TMLLP are also discussed.  相似文献   
25.
In this article, we attempt to extend and nuance the debate on intellectual property (IP) strategy, appropriation, and open innovation in dynamic and systemic innovation contexts. We present the case of four generations of mobile telecommunications systems (covering the period 1980–2015), and describe and analyze the co-evolution of strategic IP management and innovation ecosystems. Throughout this development, technologies and technological relationships were governed with different and shifting degrees of formality. Simultaneously, firms differentiated technology accessibility across actors and technologies to benefit from openness and appropriation of innovation. Our analysis shows that the discussion of competitiveness and appropriability needs to be expanded from the focal appropriability regime and complementary assets to the larger context of the innovation ecosystem and its cooperative and competitive actor relations, with dispersed complementary and substitute assets and technologies. Consequently, the shaping of complementary and substitute appropriability regimes is central when strategizing in dynamic and systemic innovation contexts. This holds important implications for the management of open innovation, innovation ecosystems, platforms, and coopetition.  相似文献   
26.
中国共产党的宪法治理经历了从根据地局部执政时期的革命宪法,新中国成立初期移植苏联宪制模式及本土化探索,到改革开放后逐步形成依宪治国与依宪执政的新局面。百年宪法治理历程曲折蹒跚,终坚定向前,经验值得弘扬。宪法治理模式的移植当慎重,宪法的权威应维护,加强党的领导和中国特色社会主义宪制创新,培育中国特色社会主义宪法文化任重道远。  相似文献   
27.
Placement of refugees and subsequent labour market integration within a host country represents a key challenge for policymakers and has emerged as one of the most divisive topics in the public debate. Immigration policy in Switzerland adopts random placement of asylum seekers across its different language regions. Hence, this policy allows to estimate the causal effect of language skills on employment chances, as refugees are exogenously placed across regions where the spoken language could either match or deviate from individual language skills. The results of this ‘natural experiment’ indicate substantially higher probabilities of finding employment when asylum seekers are placed in regions with a lingua franca that matches their individual language skills. Additionally, the findings suggest that language course participation can offset the reduced likelihood of employment in cases of a language mismatch. While random placement of refugees may be desirable for political reasons, it is detrimental to the economic integration process. Thereby, the study draws relevant conclusions for a larger European immigration policy.  相似文献   
28.
以知识流动为研究视角,将集群创新过程中的知识溢出、吸收能力内生化,构建包含三种创新模式下的产业集群演化模型,重点分析集群知识分布和知识衰减程度与集群创新模式的内在机制及其对创新产出的影响,并进行仿真实验。研究表明:不同知识分布下,混合创新模式的创新产出表现最好,外部吸收创新模式与内部自主创新模式呈现出不同的创新产出演化路径;在外部吸收创新和混合创新模式下,均匀分布型产业集群的创新产出表现最好,集中分布型表现次之,异质分布型表现最差,而在内部自主创新模式下,集中分布型则表现最好;不同创新模式对知识衰减的敏感程度呈现阶段性差异特征。这些结论对产业集群创新和可持续发展具有很好的理论和实践指导意义。  相似文献   
29.
Open innovation and absorptive capacity are two concepts based on the idea that companies can leverage the knowledge generated externally to improve their innovation performance. The aim of this paper is to analyse the joint effect of open innovation and absorptive capacity on a firm's radical innovation. Open innovation is expressed in terms of external search breadth and depth strategies and absorptive capacity is described by distinguishing between potential and realized absorptive capacity. In order to test our hypotheses, we carried out empirical research in firms operating in high-technology industries. The results indicate that internal routines and processes for absorbing external knowledge help explain radical innovation as they show a significant effect of potential and realized absorptive capacity. Also, there is a moderating effect of absorptive capacity on open innovation. Specifically, potential absorptive capacity exerts a positive effect on the relationship between external search breadth and depth and radical innovation. Realized absorptive capacity moderates the influence of external search breadth. These findings confirm the complementary nature of absorptive capacity and open innovation search strategies on radical innovation.  相似文献   
30.
Diane Stone 《Globalizations》2019,16(7):1128-1144
ABSTRACT

The ‘policy entrepreneur’ concept arises from the Multiple Streams’ theory of agenda setting in Policy Studies. Through conceptual stretching’, the concept is extended to global policy dynamics. Unlike ‘advocacy networks’ and ‘norm entrepreneurs’, the discussion addresses the strategies of ‘insider’ or ‘near-governmental’ non-state actors. The analysis advances the policy entrepreneur concept in three directions. First, the discussion develops the transnational dimensions of this activity through a case study of International Crisis Group. Second, rather than focusing on charismatic individuals, the discussion emphasizes the importance of organizational resources and reputations for policy entrepreneurship and access into international policy communities. Organizations maintain momentum behind policy solutions and pressures for change over the long term when individuals retire or depart for other positions. Third, the discussion outlines four distinct entrepreneur strategies and techniques that both individuals and organizations cultivate and deploy to enhance their power and persuasion in global policy processes and politics.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号