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   19486篇
  免费   597篇
  国内免费   1篇
管理学   2594篇
民族学   111篇
人口学   1725篇
丛书文集   74篇
教育普及   1篇
理论方法论   1746篇
综合类   181篇
社会学   9900篇
统计学   3752篇
  2023年   130篇
  2022年   80篇
  2021年   133篇
  2020年   347篇
  2019年   513篇
  2018年   607篇
  2017年   790篇
  2016年   609篇
  2015年   407篇
  2014年   569篇
  2013年   3512篇
  2012年   731篇
  2011年   681篇
  2010年   498篇
  2009年   403篇
  2008年   531篇
  2007年   484篇
  2006年   522篇
  2005年   406篇
  2004年   418篇
  2003年   350篇
  2002年   363篇
  2001年   468篇
  2000年   412篇
  1999年   402篇
  1998年   311篇
  1997年   261篇
  1996年   278篇
  1995年   288篇
  1994年   246篇
  1993年   256篇
  1992年   299篇
  1991年   294篇
  1990年   288篇
  1989年   253篇
  1988年   238篇
  1987年   201篇
  1986年   229篇
  1985年   249篇
  1984年   216篇
  1983年   191篇
  1982年   159篇
  1981年   130篇
  1980年   155篇
  1979年   170篇
  1978年   133篇
  1977年   114篇
  1976年   87篇
  1975年   91篇
  1974年   93篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
941.
Optimum experimental design theory has recently been extended for parameter estimation in copula models. The use of these models allows one to gain in flexibility by considering the model parameter set split into marginal and dependence parameters. However, this separation also leads to the natural issue of estimating only a subset of all model parameters. In this work, we treat this problem with the application of the \(D_s\)-optimality to copula models. First, we provide an extension of the corresponding equivalence theory. Then, we analyze a wide range of flexible copula models to highlight the usefulness of \(D_s\)-optimality in many possible scenarios. Finally, we discuss how the usage of the introduced design criterion also relates to the more general issue of copula selection and optimal design for model discrimination.  相似文献   
942.
943.
ABSTRACT

Incarcerated parents have complex life histories that often remain unresolved during incarceration, can continue to create barriers to prosocial success on release, and present similar intergenerational challenges for their children. This study examines the life histories of incarcerated fathers and mothers from the Pacific Northwest and how their experiences vary based on race and ethnicity. Five areas examined were exposure to trauma, child welfare involvement, mental health and substance abuse problems, juvenile justice and adult criminal justice involvement, and intergenerational criminal justice involvement. The sample comprised 359 incarcerated parents, and their racial/ethnic composition was 59% White, 14% African American, 11% multiracial, 8% Native American, and 7% Latino. Few differences were found across racial and ethnic groups. Mothers appeared more similar to each other across groups than fathers. Results illustrated similarities yet some surprising differences with national trends on key study variables. Implications for future research and intervention and prevention are discussed.  相似文献   
944.
ABSTRACT

The Washington State Legislature created the Parenting Sentencing Alternative in 2010, authorizing a substitute to total confinement for parents of minor children. The Alternative is designed to strengthen family bonds and improve parenting skills to encourage successful reintegration. An overview of the Alternative’s history, design, and implementation is presented, followed by preliminary results from an impact evaluation. A case study of a successful participant is presented, and implications for the findings are discussed.  相似文献   
945.
946.
Research shows that few foster care alumni enroll and complete post-secondary education. For those who do enroll, many experience challenges associated with academic and social adjustment and are at risk of dropping out. Many college-based programs are being developed and are available to foster care alumni to support them during their post-secondary education. This study used pre-tests, post-tests, and journal entries of seventeen participants to evaluate a strengths-based, resilience-oriented early-start program for newly enrolled students at a large public university that provides knowledge about the institution, resources (e.g., tutoring), and social support necessary for foster care alumni to make a smooth transition into college life and to increase short and long-term student success. Quantitative and qualitative findings indicate that students who participated in the early-start program showed increased confidence and competency in academic and social adjustment. Findings also showed personal growth (e.g., building resiliency) and an increased connectedness among students who participated in the program. Study findings can inform the development of new on-campus support programs and help enhance existing programming. Future research should address short and long-term outcomes and experiences of students who are former foster youth who have participated in on-campus support programs.  相似文献   
947.
The drivers of public support for redistributive policy have stimulated academic debate around the world. The majority of studies use cross‐country surveys conducted in the Organisation for Economic Co‐operation and Development countries to contribute to the debate on whether self‐interest or social values have more influence on public attitudes towards redistribution. Drawing on a phone survey conducted in 2013, this study advances the discussion by investigating public attitudes towards redistribution and social policy changes against the backdrop of buoyant government revenues in Hong Kong. The Hong Kong welfare model, best seen as a parallel to the liberal welfare state, is selective and residual. Contrary to the usual assumption, the social values hypothesis, viewing poverty as societal problems instead of individual reasons, has been supported in the Hong Kong context. It lends support to greater redistribution in a residual welfare state. The policy implications of the findings are also discussed.  相似文献   
948.
We propose a phase I clinical trial design that seeks to determine the cumulative safety of a series of administrations of a fixed dose of an investigational agent. In contrast with traditional phase I trials that are designed solely to find the maximum tolerated dose of the agent, our design instead identifies a maximum tolerated schedule that includes a maximum tolerated dose as well as a vector of recommended administration times. Our model is based on a non-mixture cure model that constrains the probability of dose limiting toxicity for all patients to increase monotonically with both dose and the number of administrations received. We assume a specific parametric hazard function for each administration and compute the total hazard of dose limiting toxicity for a schedule as a sum of individual administration hazards. Throughout a variety of settings motivated by an actual study in allogeneic bone marrow transplant recipients, we demonstrate that our approach has excellent operating characteristics and performs as well as the only other currently published design for schedule finding studies. We also present arguments for the preference of our non-mixture cure model over the existing model.  相似文献   
949.
Data envelopment analysis (DEA) is a deterministic econometric model for calculating efficiency by using data from an observed set of decision-making units (DMUs). We propose a method for calculating the distribution of efficiency scores. Our framework relies on estimating data from an unobserved set of DMUs. The model provides posterior predictive data for the unobserved DMUs to augment the frontier in the DEA that provides a posterior predictive distribution for the efficiency scores. We explore the method on a multiple-input and multiple-output DEA model. The data for the example are from a comprehensive examination of how nursing homes complete a standardized mandatory assessment of residents.  相似文献   
950.
Robust tests for the common principal components model   总被引:1,自引:0,他引:1  
When dealing with several populations, the common principal components (CPC) model assumes equal principal axes but different variances along them. In this paper, a robust log-likelihood ratio statistic allowing to test the null hypothesis of a CPC model versus no restrictions on the scatter matrices is introduced. The proposal plugs into the classical log-likelihood ratio statistic robust scatter estimators. Using the same idea, a robust log-likelihood ratio and a robust Wald-type statistic for testing proportionality against a CPC model are considered. Their asymptotic distributions under the null hypothesis and their partial influence functions are derived. A small simulation study allows to compare the behavior of the classical and robust tests, under normal and contaminated data.  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