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   6719篇
  免费   331篇
  国内免费   68篇
管理学   404篇
民族学   65篇
人口学   31篇
丛书文集   768篇
理论方法论   288篇
综合类   4504篇
社会学   337篇
统计学   721篇
  2024年   8篇
  2023年   47篇
  2022年   52篇
  2021年   72篇
  2020年   102篇
  2019年   115篇
  2018年   132篇
  2017年   141篇
  2016年   138篇
  2015年   159篇
  2014年   367篇
  2013年   573篇
  2012年   443篇
  2011年   445篇
  2010年   424篇
  2009年   414篇
  2008年   413篇
  2007年   493篇
  2006年   486篇
  2005年   470篇
  2004年   386篇
  2003年   361篇
  2002年   281篇
  2001年   218篇
  2000年   130篇
  1999年   41篇
  1998年   21篇
  1997年   28篇
  1996年   31篇
  1995年   26篇
  1994年   24篇
  1993年   14篇
  1992年   8篇
  1991年   8篇
  1990年   9篇
  1989年   10篇
  1988年   5篇
  1987年   3篇
  1986年   1篇
  1985年   3篇
  1984年   6篇
  1983年   4篇
  1982年   1篇
  1981年   2篇
  1979年   1篇
  1977年   1篇
  1975年   1篇
排序方式: 共有7118条查询结果,搜索用时 15 毫秒
21.
传统的国际关系理论,无论是现实主义、自由主义、建构主义还是科学行为主义理论,都是把主权国家抽象成一个统一的国际关系行为体。这一行为主体有一致的利益,也自然要有一致的对外政策目标和手段。在20世纪,尤其是在两次世界大战和冷战期间,这一概念抽象是非常准确的。但冷战结束以后,尤其是进入21世纪以后,这一概念抽象逐渐与国际关系的现实相违背。一方面,国家综合实力并不能直接转化为具体领域的竞争优势;另一方面,很多国家,包括超级大国在内,其对外政策的主要阻力可能不是所谓的竞争对手,而是其国内不同的利益集团。这导致传统的国际关系理论,从假设到概念和推理层面,都已经无法解释和预测今天的世界,而权力小博弈理论可以为认识多元复杂互动博弈时代的国际关系提供一个新的解释框架。  相似文献   
22.
When a candidate predictive marker is available, but evidence on its predictive ability is not sufficiently reliable, all‐comers trials with marker stratification are frequently conducted. We propose a framework for planning and evaluating prospective testing strategies in confirmatory, phase III marker‐stratified clinical trials based on a natural assumption on heterogeneity of treatment effects across marker‐defined subpopulations, where weak rather than strong control is permitted for multiple population tests. For phase III marker‐stratified trials, it is expected that treatment efficacy is established in a particular patient population, possibly in a marker‐defined subpopulation, and that the marker accuracy is assessed when the marker is used to restrict the indication or labelling of the treatment to a marker‐based subpopulation, ie, assessment of the clinical validity of the marker. In this paper, we develop statistical testing strategies based on criteria that are explicitly designated to the marker assessment, including those examining treatment effects in marker‐negative patients. As existing and developed statistical testing strategies can assert treatment efficacy for either the overall patient population or the marker‐positive subpopulation, we also develop criteria for evaluating the operating characteristics of the statistical testing strategies based on the probabilities of asserting treatment efficacy across marker subpopulations. Numerical evaluations to compare the statistical testing strategies based on the developed criteria are provided.  相似文献   
23.
The classical unconditional exact p-value test can be used to compare two multinomial distributions with small samples. This general hypothesis requires parameter estimation under the null which makes the test severely conservative. Similar property has been observed for Fisher's exact test with Barnard and Boschloo providing distinct adjustments that produce more powerful testing approaches. In this study, we develop a novel adjustment for the conservativeness of the unconditional multinomial exact p-value test that produces nominal type I error rate and increased power in comparison to all alternative approaches. We used a large simulation study to empirically estimate the 5th percentiles of the distributions of the p-values of the exact test over a range of scenarios and implemented a regression model to predict the values for two-sample multinomial settings. Our results show that the new test is uniformly more powerful than Fisher's, Barnard's, and Boschloo's tests with gains in power as large as several hundred percent in certain scenarios. Lastly, we provide a real-life data example where the unadjusted unconditional exact test wrongly fails to reject the null hypothesis and the corrected unconditional exact test rejects the null appropriately.  相似文献   
24.
We propose a class of ratio tests that is applicable whenever a cumulation (of transformed) data is asymptotically normal upon appropriate normalization. The Karhunen–Loève theorem is employed to compute weighted averages. The test statistics are ratios of quadratic forms of these averages and hence scale-invariant, also called self-normalizing: The scaling parameter cancels asymptotically. Limiting distributions are obtained. Critical values and asymptotic local power functions can be calculated by standard numerical means. The ratio tests are directed against local alternatives and turn out to be almost as powerful as optimal competitors, without being plagued by nuisance parameters at the same time. Also in finite samples they perform well relative to self-normalizing competitors.  相似文献   
25.
中、印传统体育文化蕴含了东方文明对于处世之道和养身模式的价值追求,作为东方体育文化典型代表的太极拳与瑜伽术,既是修炼身心、运动健身的重要项目,也是人们了解东方体育文化的重要媒介。跨文化比较分析表明,太极拳和瑜伽术在注重身形技法与艺术审美的结合、吐纳导引与意念游动的耦合、修身养性与天人意境的融合等方面具有共性,也有差异,体现出中、印在传统体育文化方面的异同。太极拳和瑜伽术的传承应该做到与时俱进、创新发展,其目标既不是传统竞技搏击术,也不是简单修炼养身术,而是融道德修养与身心修炼为一体的综合性运动项目。  相似文献   
26.
作为国际政治领域的重要概念,“国际社会”具有两面性。从表面上看,“国际社会”是国际行为体之间开展合作的场域,应建构和维护国际秩序的公平正义,因而在国际交往中不应以意识形态为标准和以意识形态划线;从本质上看,“国际社会”是国际行为体开展国家利益和意识形态博弈的重要场域,具有强烈的意识形态性。“国际社会”意识形态性的关键是国际话语权,其实质是国家(或国际社会成员)的国际利益。从意识形态的角度考察“国际社会”,有利于看清“国际社会”的本质,这对于深入理解国际热点问题和国际舆论的实质,特别是对于我国国际话语权的建设与提升,具有重要意义。  相似文献   
27.
《Risk analysis》2018,38(10):2193-2207
Social diffusion of information amplifies risk through processes of birth, death, and distortion of message content. Dread risk—involving uncontrollable, fatal, involuntary, and catastrophic outcomes (e.g., terrorist attacks and nuclear accidents)—may be particularly susceptible to amplification because of the psychological biases inherent in dread risk avoidance. To test this, initially balanced information about high or low dread topics was given to a set of individuals who then communicated this information through diffusion chains, each person passing a message to the next. A subset of these chains were also reexposed to the original information. We measured prior knowledge, perceived risk before and after transmission, and, at each link, number of positive and negative statements. Results showed that the more a message was transmitted the more negative statements it contained. This was highest for the high dread topic. Increased perceived risk and production of negative messages was closely related to the amount of negative information that was received, with domain knowledge mitigating this effect. Reexposure to the initial information was ineffectual in reducing bias, demonstrating the enhanced danger of socially transmitted information.  相似文献   
28.
Information before unblinding regarding the success of confirmatory clinical trials is highly uncertain. Current techniques using point estimates of auxiliary parameters for estimating expected blinded sample size: (i) fail to describe the range of likely sample sizes obtained after the anticipated data are observed, and (ii) fail to adjust to the changing patient population. Sequential MCMC-based algorithms are implemented for purposes of sample size adjustments. The uncertainty arising from clinical trials is characterized by filtering later auxiliary parameters through their earlier counterparts and employing posterior distributions to estimate sample size and power. The use of approximate expected power estimates to determine the required additional sample size are closely related to techniques employing Simple Adjustments or the EM algorithm. By contrast with these, our proposed methodology provides intervals for the expected sample size using the posterior distribution of auxiliary parameters. Future decisions about additional subjects are better informed due to our ability to account for subject response heterogeneity over time. We apply the proposed methodologies to a depression trial. Our proposed blinded procedures should be considered for most studies due to ease of implementation.  相似文献   
29.
In the contemporary multicentric world, sovereign states have to manage carefully the construction of their image, defining their role and aspirations. With the re-definition of the state centric politics, stories become relevant: communication is a form of power, and networked forms of communication are becoming progressively a way to conquer the transnational public spheres. Through strategic narratives of foreign politics, states try to set up the ‘tales’ of international affairs and foreign strategies, to suggest a world vision, a causal interpretation, determining frames that affect transnational actors’ position in the international environment. Sovereign states develop these kind of frame using tools and theories referred to the commercial branding tradition to promote and support their own policies and identity. We decided to investigate how that process is made through information diffusion on digital platforms.

In this work, it has been analyzed the content presented through Twitter posts by the Foreign Ministries accounts of four different States dissimilar for geopolitical positioning and security concerns (USA; Israel; France; Sweden), for a period of three months (9/1/2015-11/30/2015); leading to the identification of different models and characteristic patterns of self-representation.

The thematic content analysis, based on the identification of macrocategories and micro-issues, has led to the identification of different models and characteristic patterns of self-representation, determined by domestic vicissitudes, and has shown some regularities, caused by the branding vocation of autobiographical online contents.  相似文献   

30.
This study examined how Turkey uses social media as a tool for public diplomacy and how the state’s soft-power efforts have recently changed on the global stage. The researchers constructed a dataset of 2769 Twitter posts by the Turkish government’s most influential public diplomacy accounts. The analyses revealed that the focus of Turkey’s Twitter public diplomacy has become concentrated on the Middle East and North Africa (MENA) region and is thematically focused on the political values embodied by the Turkish president. The findings suggest that public diplomacy remains to be the diplomacy of the government, not of the public, and social media is used as just another tool for propaganda, not as a means of engagement with foreign publics. Further, the findings indicate the emergence of a “new” cult of personality in public diplomacy and point out the instrumental role of social media in changing the dynamics of leader-follower relationship. The study contributes to public relations theory and practice by advancing the burgeoning public diplomacy scholarship at the intersection of social media and relational approaches.  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