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   7376篇
  免费   177篇
  国内免费   1篇
管理学   990篇
民族学   33篇
人口学   760篇
丛书文集   32篇
理论方法论   661篇
综合类   90篇
社会学   3575篇
统计学   1413篇
  2023年   40篇
  2020年   97篇
  2019年   141篇
  2018年   168篇
  2017年   253篇
  2016年   178篇
  2015年   124篇
  2014年   160篇
  2013年   1301篇
  2012年   228篇
  2011年   206篇
  2010年   147篇
  2009年   134篇
  2008年   148篇
  2007年   141篇
  2006年   170篇
  2005年   152篇
  2004年   148篇
  2003年   136篇
  2002年   153篇
  2001年   164篇
  2000年   168篇
  1999年   173篇
  1998年   137篇
  1997年   133篇
  1996年   127篇
  1995年   110篇
  1994年   107篇
  1993年   110篇
  1992年   116篇
  1991年   128篇
  1990年   125篇
  1989年   144篇
  1988年   85篇
  1987年   109篇
  1986年   93篇
  1985年   114篇
  1984年   96篇
  1983年   103篇
  1982年   80篇
  1981年   81篇
  1980年   76篇
  1979年   81篇
  1978年   83篇
  1977年   60篇
  1976年   66篇
  1975年   61篇
  1974年   59篇
  1973年   48篇
  1971年   41篇
排序方式: 共有7554条查询结果,搜索用时 984 毫秒
251.
The main objective of this work is to evaluate the performance of confidence intervals, built using the deviance statistic, for the hyperparameters of state space models. The first procedure is a marginal approximation to confidence regions, based on the likelihood test, and the second one is based on the signed root deviance profile. Those methods are computationally efficient and are not affected by problems such as intervals with limits outside the parameter space, which can be the case when the focus is on the variances of the errors. The procedures are compared to the usual approaches existing in the literature, which includes the method based on the asymptotic distribution of the maximum likelihood estimator, as well as bootstrap confidence intervals. The comparison is performed via a Monte Carlo study, in order to establish empirically the advantages and disadvantages of each method. The results show that the methods based on the deviance statistic possess a better coverage rate than the asymptotic and bootstrap procedures.  相似文献   
252.
The concept of reciprocal coordinate subtangent (RCST) has been used as a useful tool to study the monotone behavior of a continuous density function and for characterizing probability distributions. In this paper, we propose a non-parametric estimator for RCST based on the censored dependent data. Asymptotic properties of the estimator are established under suitable regularity conditions. A simulation study is carried out to examine the performance of the estimator. The usefulness of the estimator is also examined through a real data.  相似文献   
253.
Statistics and Computing - In this paper, we develop a very efficient approach to the Monte Carlo estimation of the expected value of partial perfect information (EVPPI) that measures the average...  相似文献   
254.
We present an algorithm for learning oblique decision trees, called HHCART(G). Our decision tree combines learning concepts from two classification trees, HHCART and Geometric Decision Tree (GDT). HHCART(G) is a simplified HHCART algorithm that uses linear structure in the training examples, captured by a modified GDT angle bisector, to define splitting directions. At each node, we reflect the training examples with respect to the modified angle bisector to align this linear structure with the coordinate axes. Searching axis parallel splits in this reflected feature space provides an efficient and effective way of finding oblique splits in the original feature space. Our method is much simpler than HHCART because it only considers one reflected feature space for node splitting. HHCART considers multiple reflected feature spaces for node splitting making it more computationally intensive to build. Experimental results show that HHCART(G) is an effective classifier, producing compact trees with similar or better results than several other decision trees, including GDT and HHCART trees.  相似文献   
255.
We examine how soda sales changed due to the campaign attention and election outcome of a local excise tax on sugar‐sweetened beverages. Using panel data of beverage sales from university retailers in Berkeley, California, we estimate that soda purchases relative to control beverages significantly dropped immediately after the election, months before the tax was implemented in the city of Berkeley or on campus. Supplemental scanner data from off‐campus retailers reveal this result is not unique to the university setting. Our findings suggest soda tax media coverage and election outcomes can have larger effects on purchasing behavior than the tax itself. (JEL D12, H20, C23, I38, Q18)  相似文献   
256.
In this content analysis, researchers examine articles published from 2000 to 2015 in three family therapy journals, yielding a total of 948 empirical articles. The purpose is to provide an overview of the research being published, assess who is publishing, and investigate the current state of clinical effectiveness research in marriage and family therapy (MFT). Most first authors were affiliated with MFT programs and primarily included diversity and couples in their research. There was a significant increase of research on clinical process—though the number of clinical outcome studies held steady. There were no significant changes with regard to research funding. Implications support the use of innovative research methods to provide evidence of clinical effectiveness.  相似文献   
257.
Urban Ecosystems - Urbanization-induced habitat loss and alteration causes significant challenges for the survival of many species. Identifying how species respond to urbanization can yield...  相似文献   
258.
Urban Ecosystems - Loss and fragmentation of semi-natural grasslands have had negative consequences for grassland biodiversity, such as butterflies. Urban parks and other urban green spaces have so...  相似文献   
259.
While there is a global shift towards smaller families, some groups maintain relatively high fertility rates. The 2013 New Zealand census data were used to investigate the nature of fertility between ethnicities in New Zealand. The NZ Deprivation Index 2013 was used as a measure of socioeconomic status to determine the relationships with fertility. The results mirror research outside of New Zealand in that socioeconomic status is inversely correlated to fertility. Using crude average fertility rates, sole-ethnicity Pasifika and Māori ethnic groups still have substantially higher fertility than sole-ethnicity Europeans and Asians ethnic groups, even when simultaneously accounting for age, socioeconomic status, education, and religious affiliation. Christians have more children than individuals reportedly without any religion, and fertility rates drop on average for mothers who have higher formal qualifications. Our findings suggest that cultural, or other ethnic-specific factors differentially affect fertility for Māori, Pasifika, New Zealand European, and Asians as aggregated ethnic categories, respectively.  相似文献   
260.
One of the core goals of intercultural education is to develop critical and empathic reflection on social justice, particularly as related to humanistic choices and how individuals can counteract exclusion. The present article analyses the Values and Knowledge Education (VaKE) approach, which is aimed at raising awareness about implicit value-oriented priorities in decision-making. Through the Human Development and Capability Approach, the applicability of VaKE’s didactic principles is analysed in relation to young people’s perspectives on resettlement in Europe. The VaKE method was used at a 2013 summer camp in Austria with a culturally diverse group of young Europeans who were presented with a dilemma story that highlighted the complex issue of providing assistance to asylum seekers. The participants engaged in various knowledge and moral viability checks that enabled them to engage with opposing arguments. The participants evidenced critical reflection and self-scrutiny, as well as affiliation and empathic imagination, regarding problems that are encountered by asylum seekers.  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