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   8250篇
  免费   221篇
  国内免费   1篇
管理学   1128篇
民族学   33篇
人口学   742篇
丛书文集   31篇
理论方法论   706篇
综合类   138篇
社会学   3734篇
统计学   1960篇
  2020年   118篇
  2019年   178篇
  2018年   179篇
  2017年   281篇
  2016年   187篇
  2015年   161篇
  2014年   195篇
  2013年   1556篇
  2012年   255篇
  2011年   206篇
  2010年   193篇
  2009年   162篇
  2008年   233篇
  2007年   226篇
  2006年   183篇
  2005年   160篇
  2004年   138篇
  2003年   130篇
  2002年   144篇
  2001年   186篇
  2000年   164篇
  1999年   147篇
  1998年   129篇
  1997年   129篇
  1996年   125篇
  1995年   111篇
  1994年   83篇
  1993年   126篇
  1992年   137篇
  1991年   119篇
  1990年   131篇
  1989年   108篇
  1988年   107篇
  1987年   111篇
  1986年   99篇
  1985年   84篇
  1984年   115篇
  1983年   98篇
  1982年   94篇
  1981年   63篇
  1980年   93篇
  1979年   105篇
  1978年   72篇
  1977年   82篇
  1976年   70篇
  1975年   85篇
  1974年   68篇
  1973年   54篇
  1972年   62篇
  1971年   53篇
排序方式: 共有8472条查询结果,搜索用时 781 毫秒
321.
Multivariate control charts are used to monitor stochastic processes for changes and unusual observations. Hotelling's T2 statistic is calculated for each new observation and an out‐of‐control signal is issued if it goes beyond the control limits. However, this classical approach becomes unreliable as the number of variables p approaches the number of observations n, and impossible when p exceeds n. In this paper, we devise an improvement to the monitoring procedure in high‐dimensional settings. We regularise the covariance matrix to estimate the baseline parameter and incorporate a leave‐one‐out re‐sampling approach to estimate the empirical distribution of future observations. An extensive simulation study demonstrates that the new method outperforms the classical Hotelling T2 approach in power, and maintains appropriate false positive rates. We demonstrate the utility of the method using a set of quality control samples collected to monitor a gas chromatography–mass spectrometry apparatus over a period of 67 days.  相似文献   
322.
Robust parameter designs (RPDs) enable the experimenter to discover how to modify the design of the product to minimize the effect due to variation from noise sources. The aim of this article is to show how this amount of work can be reduced under modified central composite design (MCCD). We propose a measure of extended scaled prediction variance (ESPV) for evaluation of RPDs on MCCD. Using these measures, we show that we can check the error or bias associated with estimating the model parameters and suggest the values of α recommended for MCCS under minimum ESPV.  相似文献   
323.
We investigate the exact coverage and expected length properties of the model averaged tail area (MATA) confidence interval proposed by Turek and Fletcher, CSDA, 2012, in the context of two nested, normal linear regression models. The simpler model is obtained by applying a single linear constraint on the regression parameter vector of the full model. For given length of response vector and nominal coverage of the MATA confidence interval, we consider all possible models of this type and all possible true parameter values, together with a wide class of design matrices and parameters of interest. Our results show that, while not ideal, MATA confidence intervals perform surprisingly well in our regression scenario, provided that we use the minimum weight within the class of weights that we consider on the simpler model.  相似文献   
324.
This paper complements evidence on the Allais paradox from advanced countries and educated people by a novel investigation in a poor rural area. The share of Allais-type behavior is indeed high and related to indicators of “lacking ability,” such as poor education, unemployment, and little financial sophistication. Based on prospective reference theory, we extend these characteristics by biased processing of probabilistic information. Finally, we reveal that Allais-type behavior is linked to risk-related characteristics, such as risk tolerance and optimism. This indicates a potential problem as exactly the more dynamic among the poor tend to make inconsistent decisions under uncertainty.  相似文献   
325.
Mainstream approaches to chronic condition management and prevention inadequately address the needs of Māori, the Indigenous people of New Zealand. Māori health service providers (MHSPs) are uniquely placed to address the critical gap in the prevention of chronic conditions. In this paper, we report qualitative research findings investigating how prevention was being modelled, practiced and measured in selected MHSP settings. Results indicate barriers to achieving wellbeing through health service delivery. The dominant individualistic, medical conditions-focused discourse, along with responding to acute need, is a driver of service delivery norms.There are examples of shifts in organisational structure and delivery configurations that demonstrate that these norms are being challenged and reframed, in some form, by MHSPs. Consolidation of these approaches requires significant work and increased resources as well as a broader systems-level response that prioritises prevention.  相似文献   
326.
Political tolerance—the willingness to extend civil liberties to traditionally stigmatized groups—is pivotal to the functioning of democracy and the well‐being of members of stigmatized groups. Although political tolerance has traditionally been more common among American elites, we argue that as tolerance has increased, it has also diffused to less educated and less affluent segments of the population. The relative stability of political attitudes over the life course and the socialization of more recent birth cohorts in contexts of increased tolerance suggest that this diffusion of tolerance occurs across birth cohorts rather than time periods. Using age‐period‐cohort models and more than three and a half decades of repeated cross‐sectional survey data, we find persistent and robust across‐cohort declines in the importance of both income and higher education in determining levels of political tolerance. Declines in the effects of socioeconomic status are evident with tolerance toward all five out‐groups in the analysis—anti‐religionists, gays and lesbians, communists, militarists, and racists—but to varying degrees. These findings fit with a model of changes in public opinion, particularly views of civil and political rights, through processes of cultural diffusion and cohort replacement.  相似文献   
327.
The study purpose was to develop and pilot an undue influence screening tool for California’s Adult Protective Services (APS) personnel based on the definition of undue influence enacted into California law January 1, 2014. Methods included four focus groups with APS providers (n = 33), piloting the preliminary tool by APS personnel (n = 15), and interviews with four elder abuse experts and two APS administrators. Social service literature—including existing undue influence models—was reviewed, as were existing screening and assessment tools. Using the information from these various sources, the California Undue Influence Screening Tool (CUIST) was developed. It can be applied to APS cases and potentially adapted for use by other professionals and for use in other states. Implementation of the tool into APS practice, policy, procedures, and training of personnel will depend on the initiative of APS management. Future work will need to address the reliability and validity of CUIST.  相似文献   
328.
329.
Among their many responsibilities, foster parents are tasked with providing healthy food and proper nutrition to children with a variety of physical, psychological, and emotional needs. Using the lens of symbolic interactionism, this exploratory mixed methods study examined how foster parents attend to the nutritional needs of abused and neglected children. Methods used included both quantitative surveys and qualitative follow-up interviews. Surveys were completed by 23 foster parents in a large, Midwest metropolitan area. Parents reported they provided their children balanced meals, although one-third of households reported instances of food insecurity. During qualitative interviews, foster parents (N = 9) described how children arrived at their home with a variety of unhealthy eating habits, some severe in nature. Parents discussed strategies used to modify and improve eating patterns, including offering healthy food choices, having children plan meals, and gathering as a family for daily dinners. In general, parents understood the link between unhealthy eating and past childhood trauma, but also reported being unprepared for more serious eating problems like hoarding. Findings indicate that foster parents need food assistance to increase food security as well as training in assessing and responding a variety of unhealthy child eating behaviors.  相似文献   
330.
Objective: The ways that college students cope with stress, particularly interpersonal stress, may be a critical factor in determining which students are at risk for impairing mental health disorders. Using a control-based model of coping, the present study examined associations between interpersonal stress, coping strategies, and symptoms. Participants: A total of 135 undergraduate students from 2 universities. Methods: Interpersonal stress, coping strategies, depression, anxiety, and somatization were assessed via self-report. Results: Students reporting more interpersonal stress reported more depression, anxiety, and somatization, and they reported less use of engagement coping strategies and greater use of disengagement coping strategies. Engagement coping strategies accounted for a significant portion of the association between interpersonal stress and mental health symptoms. Unexpectedly, coping strategies did not moderate the association between stress and mental health symptoms. Conclusion: Interventions designed to improve students' coping strategies may be an effective way to reduce mental health problems on college campuses.  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