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   4550篇
  免费   77篇
  国内免费   3篇
管理学   507篇
民族学   30篇
人才学   1篇
人口学   395篇
丛书文集   26篇
理论方法论   341篇
综合类   89篇
社会学   2007篇
统计学   1234篇
  2023年   30篇
  2021年   25篇
  2020年   77篇
  2019年   143篇
  2018年   121篇
  2017年   202篇
  2016年   125篇
  2015年   103篇
  2014年   124篇
  2013年   949篇
  2012年   154篇
  2011年   125篇
  2010年   85篇
  2009年   105篇
  2008年   98篇
  2007年   90篇
  2006年   80篇
  2005年   78篇
  2004年   72篇
  2003年   58篇
  2002年   95篇
  2001年   93篇
  2000年   79篇
  1999年   92篇
  1998年   78篇
  1997年   69篇
  1996年   59篇
  1995年   77篇
  1994年   55篇
  1993年   59篇
  1992年   69篇
  1991年   70篇
  1990年   76篇
  1989年   61篇
  1988年   44篇
  1987年   44篇
  1986年   51篇
  1985年   59篇
  1984年   59篇
  1983年   42篇
  1982年   39篇
  1981年   34篇
  1980年   41篇
  1979年   46篇
  1978年   37篇
  1977年   26篇
  1976年   21篇
  1974年   22篇
  1972年   20篇
  1971年   21篇
排序方式: 共有4630条查询结果,搜索用时 15 毫秒
81.
This paper reports the results of a prospective experiment in which a group of approximately 4,000 participants in the Transcendental Meditation and TM-Sidhi programs of Maharishi Mahesh Yogi assembled in Washington, D.C., from June 7 to July 30, 1993. It was hypothesized that levels of violent crime in the District of Columbia would fall substantially during the Demonstration Project, as a result of the group's effect of increasing coherence and reducing stress in the collective consciousness of the District. A 27-member Project Review Board comprising independent scientists and leading citizens approved the research protocol and monitored the research process. Weekly crime data was derived from database records provided by the District of Columbia Metropolitan Police Department (DCMPD), which are used in the FBI Uniform Crime Reports. Statistical analysis considered the effect of weather variables, daylight, historical crime trends and annual patterns in the District of Columbia, as well as trends in neighboring cities. Consistent with previous research, levels of homicides, rapes and assaults (HRA crimes) correlated with average weekly temperature. Robberies approximately followed an annually recurring cycle. Time series analysis of 1993 data, controlling for temperature, showed that HRA crimes dropped significantly during the Demonstration Project, corresponding with increases in the size of the group; the maximum decrease was 23.3% (p < 2 × 10–9) [24.6% using a longer baseline, with 1988--1993 data (p < 3 × 10–5)], coincident with the peak number of participants in the group during the final week of the assembly. When the same period in each of the five previous years was examined, no significant decreases in HRA crimes were found. Robberies did not decrease significantly. However, a model that jointly estimated the effect of the Demonstration Project on both HRA crimes and robberies showed a significant reduction in violent crimes overall of 15.6% (p = 0.0008). Further analysis showed that the effect of the coherence-creating group on reducing HRA crimes could not be accounted for by additional police staffing. The time series analysis for HRA crimes gave results that are highly robust to alternative model specifications, and showed that the effect of the group size was cumulative and persisted after the Demonstration Project ended. Also, calculation of the steady state gain based on the time series model predicted that a permanent group of 4,000 coherence-creating experts in the District would have a long-term effect of reducing HRA crimes by 48%.  相似文献   
82.
In this article, we first propose the modified Hannan–Rissanen Method for estimating the parameters of autoregressive moving average (ARMA) process with symmetric stable noise and symmetric stable generalized autoregressive conditional heteroskedastic (GARCH) noise. Next, we propose the modified empirical characteristic function method for the estimation of GARCH parameters with symmetric stable noise. Further, we show the efficiency, accuracy and simplicity of our methods with Monte-Carlo simulation. Finally, we apply our proposed methods to model the financial data.  相似文献   
83.
84.
Using a multi‐informant approach, this study examined emotion regulation within the social context of White and Black adolescent peer groups by assessing two aspects of sadness expression management (i.e., inhibition, disinhibition) and their linkages to peer acceptance and social functioning as a function of gender and ethnicity. Seventh‐ and eighth‐grade adolescents (N = 155, 52 percent female, 54.8 percent Black) completed self‐reports and peer nominations of sadness management and sociometric ratings of peer acceptance. Parents rated their child's social competence and social problems. Results revealed specific patterns of sadness regulation across informants that were associated with social functioning and varied by gender, but not ethnicity. Boys were more likely than girls to minimize sadness displays; boys who violated this pattern had lower peer acceptance and higher parent‐rated social problems. In contrast, although girls were rated as displaying overt sadness more frequently than boys, this was unrelated to peer acceptance.  相似文献   
85.
86.
Bistrategic resource control entails using both coercive and prosocial strategies in competition for resources. The present study sought to clarify whether bistrategic involves more than simply using both strategies some of the time. Examining 88 preschoolers' coercion and prosociality over an entire school year, results showed that coercive resource control was used most frequently at the start of the school year, presumably to access resources and establish social dominance. Rates of prosocial resource control increased over the school year, and socially dominant preschoolers showed higher rates compared with peers, presumably to maintain resource control while keeping peers as allies. Socially dominant preschoolers also used reconciliation more often than peers, resulting in higher rates of affiliation between former competitors and more positive peer regard from fall to spring. Findings are discussed in terms of resource control theory and the importance of situating social behaviors within the behavioral and relationship context in which they are embedded.  相似文献   
87.
The effect of bioaerosol size was incorporated into predictive dose‐response models for the effects of inhaled aerosols of Francisella tularensis (the causative agent of tularemia) on rhesus monkeys and guinea pigs with bioaerosol diameters ranging between 1.0 and 24 μm. Aerosol‐size‐dependent models were formulated as modification of the exponential and β‐Poisson dose‐response models and model parameters were estimated using maximum likelihood methods and multiple data sets of quantal dose‐response data for which aerosol sizes of inhaled doses were known. Analysis of F. tularensis dose‐response data was best fit by an exponential dose‐response model with a power function including the particle diameter size substituting for the rate parameter k scaling the applied dose. There were differences in the pathogen's aerosol‐size‐dependence equation and models that better represent the observed dose‐response results than the estimate derived from applying the model developed by the International Commission on Radiological Protection (ICRP, 1994) that relies on differential regional lung deposition for human particle exposure.  相似文献   
88.
89.
Abstract

The present study confirms the influential role of a positively and a negatively correlated auxiliary variables in enhancing the precision of estimates of current population mean in two occasion rotation (successive) sampling. Exponential-type estimators of current population mean have been proposed for three different situations: (i) the information on a positively correlated auxiliary variable is readily available on both occasions (ii) the information on a negatively correlated auxiliary variable is readily available on both occasions and (iii) the information on both positively and negatively correlated auxiliary variables are readily available on both the occasions. The characteristics of the proposed estimators have been explored and their efficacious performances are compared with the natural and recent contemporary estimators. Optimum replacement strategies of the proposed estimation procedures have been formulated. Simulation and empirical studies are carried out to justify the proposition of the proposed estimators and appropriate recommendations have been put forward to the survey practitioners.  相似文献   
90.
In this article, we propose a new class of distributions defined by a quantile function, which nests several distributions as its members. The quantile function proposed here is the sum of the quantile functions of the generalized Pareto and Weibull distributions. Various distributional properties and reliability characteristics of the class are discussed. The estimation of the parameters of the model using L-moments is studied. Finally, we apply the model to a real life dataset.  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