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   3186篇
  免费   104篇
  国内免费   58篇
管理学   257篇
民族学   13篇
人才学   3篇
人口学   90篇
丛书文集   233篇
理论方法论   160篇
综合类   1631篇
社会学   310篇
统计学   651篇
  2024年   1篇
  2023年   8篇
  2022年   11篇
  2021年   25篇
  2020年   38篇
  2019年   50篇
  2018年   76篇
  2017年   81篇
  2016年   63篇
  2015年   77篇
  2014年   150篇
  2013年   379篇
  2012年   174篇
  2011年   230篇
  2010年   165篇
  2009年   216篇
  2008年   189篇
  2007年   204篇
  2006年   159篇
  2005年   133篇
  2004年   146篇
  2003年   140篇
  2002年   116篇
  2001年   98篇
  2000年   70篇
  1999年   57篇
  1998年   23篇
  1997年   25篇
  1996年   15篇
  1995年   25篇
  1994年   24篇
  1993年   14篇
  1992年   6篇
  1991年   9篇
  1990年   7篇
  1989年   2篇
  1988年   4篇
  1987年   3篇
  1986年   2篇
  1985年   23篇
  1984年   22篇
  1983年   22篇
  1982年   12篇
  1981年   15篇
  1980年   10篇
  1979年   16篇
  1978年   10篇
  1977年   3篇
排序方式: 共有3348条查询结果,搜索用时 15 毫秒
61.
Regulatory shifts in US border policy set in motion through implementation of the Western Hemisphere Travel Initiative are concurrent with recent formal and functional changes to the US passport. This article examines these modifications interweaving themes of boundary, mobility, and identity. The study focuses on the tripartite means by which the state employs the passport: as the primary affixer of national identity; as a mediator of contact and mobility across national boundaries; and as a mode for the projection of a certain territorial discourse to its citizenry and ‘others.’ These concepts are developed through an analysis of the narrative and iconic representations contained within the new book itself; material sources from government archives; as well as discussions and interviews with US State Department functionaries closely associated with the design and distribution of the new e-passport. Through the latter examination, a view is afforded into the process by which key state documents are crafted and an inherent tension revealed within an agency charged with establishing a particular unifying ‘brand’ for the preeminent instrument of national identification, whilst dutifully acknowledging the diverse constituency of a nation that historically fashions itself as one constructed from the many. In conclusion, the study suggests that the new passport is the handiwork of a plethora of state actors and a servant of many masters, for it is not only a facilitator of mobility and a vouchsafe for the identity of the bearer, but also, a tiny but significant piece of US property, itself an agent of border maintenance and boundary construction that enables the state to lay claim to its citizenry.  相似文献   
62.
本文概述了当前美国有线电视行业/付费视频行业的局势,以及一些重要问题和面临的挑战,展望了未来的视频市场,概述了一个未来视频/宽带市场的战略愿景,然后回归到政策建议及具体的立法和管制行动。这将帮助我们在最短的、可操作的时间内通向一个开放的、非歧视性的、无处不在的宽带网络。  相似文献   
63.
This short article shows an unified approach to representing and computing the cumulative distribution function for noncentral t, F, and χ2. Unlike the existing algorithms, which involve different expansion and/or recurrence, the new approach consistently represents all the three noncentral cumulative distribution functions as the integral of the normal cumulative distribution function and χ2 density function.  相似文献   
64.
Let T2 i=z′iS?1zi, i==,…k be correlated Hotelling's T2 statistics under normality. where z=(z′i,…,z′k)′ and nS are independently distributed as Nkp((O,ρ?∑) and Wishart distribution Wp(∑, n), respectively. The purpose of this paper is to study the distribution function F(x1,…,xk) of (T2 i,…,T2 k) when n is large. First we derive an asymptotic expansion of the characteristic function of (T2 i,…,T2 k) up to the order n?2. Next we give asymptotic expansions for (T2 i,…,T2 k) in two cases (i)ρ=Ik and (ii) k=2 by inverting the expanded characteristic function up to the orders n?2 and n?1, respectively. Our results can be applied to the distribution function of max (T2 i,…,T2 k) as a special case.  相似文献   
65.
针对大庆外围油田特低渗透油藏剩余油潜力大、井网加密效益差、水驱采收率低等问题,提出了特低渗透油藏 CO2驱技术。通过细管实验和天然岩芯 CO2 驱油实验,确定了 CO2 与高台子油田原油的最小混相压力,评价了特低渗透砂岩油藏 CO2 驱油效果。实验结果表明,CO2 驱可以应用于高台子油田,并取得较好的驱油效果。当天然岩芯空气渗透率为0.58 mD 时,在水驱基础上,气驱可以进一步提高采收率 8% 以上,特低渗透油藏实施 CO2 驱油技术是可行的。  相似文献   
66.
The study demonstrates the key role of expenditure policies in explaining fiscal developments during EMU in the euro area, its three largest members and four “macro-imbalances” countries. It compares actual primary expenditure trends with those that would have prevailed if countries had followed neutral policies based on expenditure rules since the start of EMU. Moreover, the implications for debt trends are calculated. Results show that all sample countries except Germany applied expansionary expenditure policies already before the crisis. Consequently, expenditure and debt paths were much higher compared to a counterfactual neutral expenditure stance. Rule-based expenditure policies could have led to much safer fiscal positions much more in line with the EU's Stability and Growth Pact. An empirical analysis of the determinants of countries’ expenditure stance confirms the need for stronger fiscal rules and institutions in the euro area.  相似文献   
67.
Rising healthcare costs have sparked debate about the best way to provide high‐quality affordable health insurance. We discuss the potential for regulated insurance markets to outperform single‐payer public insurance. We use as an example the private Medicare plans that now provide insurance to almost a third of seniors in the United States. The evidence suggests that private plans can limit costs and potentially appeal to enrollees, and that well‐designed risk adjustment can mitigate market failures due to adverse selection. However, fostering competition between insurers, especially in smaller markets, is difficult. We discuss how future research might illuminate the relative advantages of public and private health insurance.  相似文献   
68.
Who becomes a top politician in China? We focus on provincial leaders—a pool of candidates for top political office—and examine how their chances of promotion depend on their performance in office and connections with top politicians. Our empirical analysis, based on the curriculum vitae of Chinese politicians, shows that connections and performance are complements in the Chinese political selection process. This complementarity is stronger the younger provincial leaders are relative to their connected top leaders. To provide one plausible interpretation of these empirical findings, we propose a simple theory in which the complementarity arises because connections foster loyalty of junior officials to senior ones, thereby allowing incumbent top politicians to select competent provincial leaders without risking being ousted. Our findings shed some light on why a political system known for patronage can still select competent leaders.  相似文献   
69.
本文引入了同时考虑用能权与碳排放权初始分配的零和DEA方法,从公平与效率视角对比分析了历史法与零和DEA方法两种分配方式的适用性,并应用市场交易模型检验了不同初始分配方式对各地区交易行为的影响。研究结果表明,零和DEA方法能够提高用能权与碳排放权初始分配的公平性,但却是以牺牲前沿技术效率水平为代价。其次,完善的市场机制能够提高基于零和DEA方法调配用能权与碳排放权的配置效率,生产技术水平较高的地区可以通过出售多余的用能权和碳排放权来获得额外收益,有利于促进绿色技术创新;相反,历史法容易导致高耗能、高排放的地区在初始分配中获得较多的用能权和碳排放权,不利于正向促进技术进步。最后,当市场机制不完善时,基于零和DEA方法配置用能权和碳排放权,可能会抑制技术进步,而基于历史法的初始分配方式则至少可以在短期内维持现有生产技术水平。  相似文献   
70.
依据“健康第一”、“以人为本”的理念,结合体育教学基本理论,针对我国大学生体质健康状况急剧下降的严峻形式,创造性地提出高校公共体育“2S”教学理念,强调“微笑”与“出汗”的相互融合。该教学理念重视快乐体育教学模式、成功体育教育模式的价值,突出教学内容专项化,教学过程的科学负荷,教学方法的多样化,强调教学组织以学生为主体,教学评价重视过程评价。  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