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   1837篇
  免费   46篇
  国内免费   12篇
管理学   101篇
民族学   5篇
人口学   129篇
丛书文集   33篇
理论方法论   20篇
综合类   516篇
社会学   21篇
统计学   1070篇
  2024年   1篇
  2023年   9篇
  2022年   13篇
  2021年   20篇
  2020年   34篇
  2019年   31篇
  2018年   60篇
  2017年   78篇
  2016年   52篇
  2015年   47篇
  2014年   66篇
  2013年   479篇
  2012年   145篇
  2011年   82篇
  2010年   67篇
  2009年   73篇
  2008年   89篇
  2007年   73篇
  2006年   70篇
  2005年   57篇
  2004年   52篇
  2003年   48篇
  2002年   35篇
  2001年   37篇
  2000年   35篇
  1999年   17篇
  1998年   22篇
  1997年   14篇
  1996年   8篇
  1995年   12篇
  1994年   11篇
  1993年   5篇
  1992年   7篇
  1991年   9篇
  1990年   7篇
  1989年   8篇
  1988年   6篇
  1987年   1篇
  1985年   2篇
  1984年   1篇
  1983年   3篇
  1982年   3篇
  1980年   2篇
  1978年   2篇
  1976年   1篇
  1975年   1篇
排序方式: 共有1895条查询结果,搜索用时 156 毫秒
111.
杨悠  范忠才 《现代妇女》2014,(2):200-200,211
目的:研究血栓弹力图在经皮冠状动脉介入治疗(PCI)患者中,使用血栓弹力图所测定的血小板抑制率的波动及临床疗效作用。方法:选取我院2012年1月份至2013年12月份收治的200例冠心病PCI治疗患者,应用血栓弹力图分析仪测定其二磷酸腺苷(ADP)途径诱导的血小板抑制率数据,根据抑制率差异分为3组,抑制率70%的为合格组,抑制率30%的为不合格组,入选不合格组再次分为2组,1组保持常规剂量治疗不变,另一组为大剂量治疗组。结果:随访半年的记录,记录一般情况及严重心脏不良事件发生情况。结果:随访的6个月中,共发生不良事件28例,其中合格组10例(9.6%),常规治疗组11例(22.4%),大剂量治疗组7例(14.9%),3组中不良事件发生率比常规治疗组大于大剂量治疗组,大剂量治疗组大于合格组,统计学上有明显差异(P0.05)。结论:血栓弹力图在PCI患者抗血小板治疗中应用具有一定的指导意义。  相似文献   
112.
李扬 《科学发展》2014,(10):5-8
中国地方政府债务问题形成的主要原因,一是政府过多地、直接地参与经济活动,二是城市化加速导致地方政府举债。对于中国地方政府债务问题,总体判断仍为风险可控。一是地方政府加上中央政府的债务占GDP的比例在40%以内,远低于60%的债务率标准。二是中央政府有非常强的控制能力,在各级政府间平衡债权债务,使得中国加总的净债务率较低。三是中国整体的资产负债表仍然健康,尤其是中央政府保持相当健康的资产负债表。对地方政府债务问题,体制性的解决办法是治本之道。要从根本上解决中国地方政府不规范借债问题,须建立规范化的地方政府举债融资机制。  相似文献   
113.
由于经济体系中的流动性过剩问题日趋严重,中国人民银行连续上调存款准备金率,以期通过这种重量级的货币政策来收缩银行体系的货币供给,从而有效地控制流动性过剩.存款准备金率政策的最终政策效应,有赖于通过银行体系内部商业银行的资产负债管理行为而达成.然而,这一货币政策传导机制本身充满着诸多相互作用的变量和相应的行为选择.本文就这一问题出发,深入地解析了存款准备金率政策通过商业银行资产负债管理而起作用的内在微观结构.  相似文献   
114.
The objective of this paper is to study the Phase I monitoring and change point estimation of autocorrelated Poisson profiles where the response values within each profile are autocorrelated. Two charts, the SLRT and the Hotelling's T2, are proposed along with an algorithm for parameter estimation. The detecting power of the proposed charts is compared using simulations in terms of the signal probability criterion. The performance of the SLRT method in estimating the change point in the regression parameters is also evaluated. Moreover, a real data example is presented to illustrate the application of the methods.  相似文献   
115.
The aim of this paper is to introduce an efficient Bayesian sampling procedure for exponential distribution with type-I censoring. An online inspection method is suggested to reach a Bayes decision prior the termination time of life test. Bayesian sampling plans (BSPs) with quadratic loss function are established to illustrate the use of the proposed method. Some BSPs are tabulated, and the performance of the proposed BSPs is compared with two existing competitive methods. Numerical results indicate that a significant reduction in the experimental time over the conventional BSP can be achieved when the online inspection method is applied.  相似文献   
116.
The likelihood ratio method is used to construct a confidence interval for a population mean when sampling from a population with certain characteristics found in many applications, such as auditing. Specifically, a sample taken from this type of population usually consists of a very large number of zero values, plus a small number of nonzero values that follow some continuous distribution. In this situation, the traditional confidence interval constructed for the population mean is known to be unreliable. This article derives confidence intervals based on the likelihood-ratio-test approach by assuming (1) a normal distribution (normal algorithm) and (2) an exponential distribution (exponential algorithm). Because the error population distribution is usually unknown, it is important to study the robustness of the proposed procedures. We perform an extensive simulation study to compare the percentage of confidence intervals containing the true population mean using the two proposed algorithms with the percentage obtained from the traditional method based on the central limit theorem. It is shown that the normal algorithm is the most robust procedure against many different distributional error assumptions.  相似文献   
117.
We study a hypothesis testing problem involving the location model suggested by Olkin and Tate (1961). Specifically, we derive a likelihood ratio lest of the associated location hypothesis as an alternative to the conventional method of carrying out separate tests for each of the parameters. A small sample Monte Carlo comparison indicates the general superiority of the former in terms of statistical power. We also comment briefly on the properties of the test.  相似文献   
118.
The generalized standard two-sided power (GTSP) distribution was mentioned only in passing by Kotz and van Dorp Beyond Beta, Other Continuous Families of Distributions with Bounded Support and Applications, World Scientific Press, Singapore, 2004. In this paper, we shall further investigate this three-parameter distribution by presenting some novel properties and use its more general form to contrast the chronology of developments of various authors on the two-parameter TSP distribution since its initial introduction. GTSP distributions allow for J-shaped forms of its pdf, whereas TSP distributions are limited to U-shaped and unimodal forms. Hence, GTSP distributions possess the same three distributional shapes as the classical beta distributions. A novel method and algorithm for the indirect elicitation of the two-power parameters of the GTSP distribution is developed. We present a Project Evaluation Review Technique example that utilizes this algorithm and demonstrates the benefit of separate powers for the two branches of activity GTSP distributions for project completion time uncertainty estimation.  相似文献   
119.
The paper derives Bartlett corrections for improving the chisquare approximation to the likelihood ratio statistics in a class of location-scale family of distributions, which encompasses the elliptical family of distributions and also asymmetric distributions such as the extreme value distributions. We present, in matrix notation, a Bartlett corrected likelihood ratio statistic for testing that a subset of the nonlinear regression coefficients in this class of models equals a given vector of constants. The formulae derived are simple enough to be used analytically to obtain several Bartlett corrections in a variety of important models. We show that these formulae generalize a number of previously published results. We also present simulation results comparing the sizes and powers of the usual likelihood ratio tests and their Bartlett corrected versions when the scale parameter is considered known and when this parameter is uncorrectly specified.  相似文献   
120.
For square contingency tables with ordered categories, there may be some cases that one wants to analyze them by considering collapsed tables with some adjacent categories combined in the original table. This paper proposes three kinds of new models which have the structure of point-symmetry (PS), quasi point-symmetry and marginal point-symmetry for collapsed square tables. This paper also gives a decomposition of the PS model for collapsed square tables. The father's and his daughter's occupational mobility data are analyzed using new models.  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