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   22248篇
  免费   360篇
  国内免费   2篇
管理学   3088篇
民族学   151篇
人口学   3469篇
丛书文集   49篇
理论方法论   1533篇
综合类   455篇
社会学   9702篇
统计学   4163篇
  2023年   86篇
  2021年   80篇
  2020年   233篇
  2019年   308篇
  2018年   2000篇
  2017年   2088篇
  2016年   1379篇
  2015年   309篇
  2014年   378篇
  2013年   2354篇
  2012年   778篇
  2011年   1450篇
  2010年   1306篇
  2009年   1022篇
  2008年   1128篇
  2007年   1304篇
  2006年   256篇
  2005年   436篇
  2004年   444篇
  2003年   373篇
  2002年   286篇
  2001年   249篇
  2000年   229篇
  1999年   203篇
  1998年   167篇
  1997年   170篇
  1996年   190篇
  1995年   143篇
  1994年   125篇
  1993年   162篇
  1992年   187篇
  1991年   167篇
  1990年   162篇
  1989年   139篇
  1988年   157篇
  1987年   128篇
  1986年   123篇
  1985年   121篇
  1984年   144篇
  1983年   137篇
  1982年   118篇
  1981年   85篇
  1980年   115篇
  1979年   127篇
  1978年   111篇
  1977年   98篇
  1976年   93篇
  1975年   106篇
  1974年   79篇
  1972年   74篇
排序方式: 共有10000条查询结果,搜索用时 640 毫秒
431.
To recover a low-rank structure from a noisy matrix, truncated singular value decomposition has been extensively used and studied. Recent studies suggested that the signal can be better estimated by shrinking the singular values as well. We pursue this line of research and propose a new estimator offering a continuum of thresholding and shrinking functions. To avoid an unstable and costly cross-validation search, we propose new rules to select two thresholding and shrinking parameters from the data. In particular we propose a generalized Stein unbiased risk estimation criterion that does not require knowledge of the variance of the noise and that is computationally fast. A Monte Carlo simulation reveals that our estimator outperforms the tested methods in terms of mean squared error on both low-rank and general signal matrices across different signal-to-noise ratio regimes. In addition, it accurately estimates the rank of the signal when it is detectable.  相似文献   
432.
433.
This paper will illuminate one dimension of self-disclosure as it relates to the inescapable presence of the body in treatment, and the female clinician’s ability to bring her physical body into clinical discussions during an encounter with a female client with an eating disorder. Although the clinical literature on eating disorders validates that transference and countertransference issues are particularly powerful, it generally neglects the exploration of these issues specific to the body’s physical presentation. Since body dissatisfaction is increasingly normative for women today, female clinicians need to have a theoretical road map on which to rely when they encounter a shared body experience. Thus, in order to encourage discussions of the therapist’s body in clinical social work practice, the body needs to be situated in a larger theoretical framework within which it can be explained and located; this framework is object relations theory viewed through an intersubjective lens. Concepts from object relations theory will demonstrate the importance of the body in the clinical exchange by highlighting the parallel between Winnicott’s ‘good enough’ mother and the ‘good enough’ therapist’s body. When the therapist is able to judiciously invite discussions of her body into the clinical arena, the client is given the opportunity to move from object relating to object usage. A case presentation exemplifies how this conceptual framework can be applied to clinical social work practice, strengthening the relationship between knowing and doing.  相似文献   
434.
This paper contributes to the discussion on the effects of the number of children on female employment in Europe. Most previous research has either (1) compared these effects across countries, assuming an exogeneity of family size; or (2) used methods that dealt with endogeneity of family size, but that focused on single countries. We combine these two approaches by taking a cross-country comparative perspective and applying quasi-experimental methods. We use instrumental variable models, with multiple births as instruments, and the harmonized data from the European Survey on Income and Living Conditions (EU-SILC). We examine the cross-country variation in the effects of family size on maternal employment across groups of European countries with different welfare state regimes. This step gives us an opportunity to investigate whether the revealed cross-country differences in the magnitude of the effect of the family size on maternal employment can be attributed to the diversity of European institutional arrangements, as well as the cultural and the structural conditions for combining work and family duties.  相似文献   
435.
Self-Rated Health (SRH) is becoming one of the most popular indicator of population health. Nevertheless, a limited understanding still remains about the elements to which individuals refer when evaluating their health and how those elements act and interact in the evaluation process. In this study we use a structural equation model with latent variables to identify direct and indirect influences of various health dimensions (chronic morbidity, functional abilities and emotional health) and socio-demographic covariates (age, gender and education) on poor SRH. The sample consists of 25,183 Italian elderly aged 65 years and over, interviewed in the 2005 National Health Interview Survey. The results have pointed out the higher direct effect of psychological and emotional health on SRH, while the higher total effect is caused by chronic morbidity, which influences SRH both directly and altering functional and emotional health. Growing older, being a woman and having a low education negatively impacts on SRH. However, this is almost completely the result of the indirect effect exerted by the covariates, while their direct effect is not significant (gender), negative (age) or very modest (education).  相似文献   
436.
Inconsistent censoring in the public‐use March Current Population Survey (CPS) limits its usefulness in measuring labor earnings trends, as previous approaches for imputing topcoded earnings systematically understate top earnings. Using Pareto estimation methods with less‐censored internal data, we create an enhanced cell‐mean series to capture top earnings in the public‐use data. Annual earnings inequality trends since 1963 using our series largely mirror those found by Kopczuk, Saez, and Song using social security administration data for commerce and industry workers. When we extend our analysis to 2013 and consider all workers, earnings inequality levels are higher but its growth is more modest. (JEL C81, D31, J01)  相似文献   
437.
An analytic methodology for patient enrollment modeling using a Poisson-gamma model is developed by Anisimov & Fedorov (2005–2007). For modeling hierarchic processes associated with enrollment, a new methodology using evolving stochastic processes is proposed. This provides rather general and unified framework to describe various operational processes associated with enrollment. The technique for calculating predictive distributions, mean, and credibility bounds for evolving processes is developed. Some applications to modeling operational characteristics in clinical trials are considered with focus to modeling events associated with incoming and follow-up patients in different settings. For these models, predictive characteristics are derived in a closed form.  相似文献   
438.
Availability of free public education induces a transfer in kind among households with school age children. We provide evidence of the redistributive character of public education provision. We estimate structural quantile treatment effects of household income on the distribution of expected educational transfers in kind. Under the assumption that education quality is a normal good, better services (ancillary to the core education mission) supplied by private schools increase quality therein and reduce the incentives for wealthy households to enroll in public education. Because of these incentives, rich families benefit less from educational transfers in kind and the public education system is redistributive. Using household survey data from Italy, we find that an increase in net income reduces the value of the expected educational in kind transfers for compulsory education.  相似文献   
439.
Using a rich longitudinal data set of married couples from the Korean Labor and Income Panel Study, this article seeks to uncover the intramarital allocation of experienced utility and its drivers. We find both substantial gains from marriage and effects of relative predicted earnings outside of marriage on relative gains from marriage. These findings are consistent with cooperative bargaining models and with models viewing individuals as having a demand for household production services by a spouse, with market forces influencing the price of such services. In addition, we find that men benefit more from marriage than women and that this gender gap is more pronounced for older couples. This is likely to be due to social norms and prescribed gender roles which are more prevalent within the older generation.  相似文献   
440.
Previous empirical literature on the relation between intergenerational transfer of assets and services has mostly focused on contemporary exchanges. By contrast, we provide novel evidence showing that parents who helped their adult children in the past are rewarded by higher chances of receiving informal care later in life. To this end we use Italian data containing precise retrospective information about the help with housing that couples received from their parents when they got married, such as a real estate donation or down payment. Our estimates show that this type of past help is positively associated with the current provision of informal care to the parents. This result is robust to controlling for a large set of individual and family characteristics and is only partially due to increased geographical proximity. We suggest that this finding can be explained by mixed self-interest motives, related to theories based on either bilateral exchange or the presence of a third generation (grandchildren), such as the demonstration effect model or the family constitution model.  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