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   2966篇
  免费   168篇
管理学   365篇
民族学   37篇
人口学   321篇
丛书文集   7篇
理论方法论   286篇
综合类   61篇
社会学   1483篇
统计学   574篇
  2023年   40篇
  2022年   36篇
  2021年   44篇
  2020年   119篇
  2019年   115篇
  2018年   216篇
  2017年   240篇
  2016年   193篇
  2015年   122篇
  2014年   137篇
  2013年   532篇
  2012年   229篇
  2011年   127篇
  2010年   109篇
  2009年   93篇
  2008年   83篇
  2007年   69篇
  2006年   62篇
  2005年   52篇
  2004年   47篇
  2003年   49篇
  2002年   43篇
  2001年   34篇
  2000年   21篇
  1999年   22篇
  1998年   17篇
  1997年   14篇
  1996年   11篇
  1995年   12篇
  1994年   14篇
  1993年   11篇
  1992年   12篇
  1991年   12篇
  1990年   12篇
  1989年   10篇
  1988年   12篇
  1987年   9篇
  1986年   10篇
  1985年   14篇
  1984年   8篇
  1983年   8篇
  1982年   11篇
  1980年   7篇
  1979年   10篇
  1978年   9篇
  1977年   10篇
  1976年   12篇
  1975年   10篇
  1974年   7篇
  1973年   11篇
排序方式: 共有3134条查询结果,搜索用时 93 毫秒
41.
42.
43.
44.
Several colorectal cancer (CRC) screening models have been developed describing the progression of adenomas to CRC. Currently, there is increasing evidence that serrated lesions can also develop into CRC. It is not clear whether screening tests have the same test characteristics for serrated lesions as for adenomas, but lower sensitivities have been suggested. Models that ignore this type of colorectal lesions may provide overly optimistic predictions of the screen‐induced reduction in CRC incidence. To address this issue, we have developed the Adenoma and Serrated pathway to Colorectal CAncer (ASCCA) model that includes the adenoma‐carcinoma pathway and the serrated pathway to CRC as well as characteristics of colorectal lesions. The model structure and the calibration procedure are described in detail. Calibration resulted in 19 parameter sets for the adenoma‐carcinoma pathway and 13 for the serrated pathway that match the age‐ and sex‐specific adenoma and serrated lesion prevalence in the COlonoscopy versus COlonography Screening (COCOS) trial, Dutch CRC incidence and mortality rates, and a number of other intermediate outcomes concerning characteristics of colorectal lesions. As an example, we simulated outcomes for a biennial fecal immunochemical test screening program and a hypothetical one‐time colonoscopy screening program. Inclusion of the serrated pathway influenced the predicted effectiveness of screening when serrated lesions are associated with lower screening test sensitivity or when they are not removed. To our knowledge, this is the first model that explicitly includes the serrated pathway and characteristics of colorectal lesions. It is suitable for the evaluation of the (cost)effectiveness of potential screening strategies for CRC.  相似文献   
45.
The objective of this work was to summarise and evaluate the evidence showing that physical activity is a protector factor as regards falls in older people. Relevant studies were identified through a systematic search in the MEDLINE and Cochrane Library, under the keywords of accidental fall/numerical data and risk factors, and with the bibliographies of retrieved papers. The combined odds ratio (OR) [95% confidence interval] for physical activity was 0.75 [0.64, 0.88] with moderate heterogeneity (I 2?=?33%). For fall injury, it was 0.59 [0.47, 0.74] and, for falls in general, it rose to 0.94 [0.76, 1.17] with nil heterogeneity. The combined OR for sedentary factors was 1.14 [1.10, 1.82] with moderate heterogeneity (I 2?=?36%). Regular physical activity in daily life yields significant reduction in falls in older people, especially falls with injuries.  相似文献   
46.
Efforts to improve child survival in lower-income countries typically focus on fundamental factors such as economic resources and infrastructure provision, even though research from post-industrial countries confirms that family instability has important health consequences. We tested the association between maternal union instability and children’s mortality risk in Africa, Latin America and the Caribbean, and Asia using children’s actual experience of mortality (discrete-time probit hazard models) as well as their experience of untreated morbidity (probit regression). Children of divorced/separated mothers experience compromised survival chances, but children of mothers who have never been in a union generally do not. Among children of partnered women, those whose mothers have experienced prior union transitions have a higher mortality risk. Targeting children of mothers who have experienced union instability—regardless of current union status—may augment ongoing efforts to reduce childhood mortality, especially in Africa and Latin America where union transitions are common.  相似文献   
47.
By adopting a multidimensional approach to environmental attitudes (apathy, anthropocentrism, connectedness and emotional affinity with nature), this study explores the relationships between these dimensions, social dominance orientation (SDO) and political orientation. Two hundred and sixty-two Chilean university students filled out an ad hoc online questionnaire. Two confirmatory factorial analyses showed the four typologies of environmental attitudes and the two factors for SDO, which are labelled group dominance and opposition to equality. Through hierarchical regressions, group dominance showed higher explanatory power of environmental attitudes than political orientation. Furthermore, using the bootstrap procedure we showed that group dominance mediated between political orientation and attitudes of apathy, anthropocentrism and connectedness, while opposition to equality mediated between apathy and emotional affinity. We conclude that SDO is an important variable for measuring political ideology while also providing new nuances when analysing the relationships with environmental attitudes.  相似文献   
48.
The skew-generalized-normal distribution [Arellano-Valle, RB, Gómez, HW, Quintana, FA. A new class of skew-normal distributions. Comm Statist Theory Methods 2004;33(7):1465–1480] is a class of asymmetric normal distributions, which contains the normal and skew-normal distributions as special cases. The main virtues of this distribution is that it is easy to simulate from and it also supplies a genuine expectation–maximization (EM) algorithm for maximum likelihood estimation. In this paper, we extend the EM algorithm for linear regression models assuming skew-generalized-normal random errors and we develop a diagnostics analyses via local influence and generalized leverage, following Zhu and Lee's approach. This is because Cook's well-known approach would be more complicated to use to obtain measures of local influence. Finally, results obtained for a real data set are reported, illustrating the usefulness of the proposed method.  相似文献   
49.
The purpose of this article is to explore the origins of dissent public relations and to establish its emergence in the context of the ancient Greek comedy represented by Aristophanes. Indeed, Attic Comedy (also known as Old Comedy) was the first great example of today’s mass communication, in which political satire was used to dissent and protest against political and social circumstances in fifth-century BC Athens. This situation was conditioned by the Peloponnesian War and its political, economic and social consequences. From this perspective, this article also constitutes an investigation into the intellectual history of public relations, of which Aristophanes can be considered to be one of the first practitioners.  相似文献   
50.
Social Indicators Research - Considerable literature exists on the acculturation and adaptation of immigrants. For the most part, studies looked at their psychological and social adaptation to the...  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