全文获取类型
收费全文 | 4518篇 |
免费 | 236篇 |
专业分类
管理学 | 638篇 |
民族学 | 34篇 |
人才学 | 2篇 |
人口学 | 373篇 |
丛书文集 | 26篇 |
理论方法论 | 604篇 |
综合类 | 33篇 |
社会学 | 2491篇 |
统计学 | 553篇 |
出版年
2023年 | 45篇 |
2022年 | 25篇 |
2021年 | 52篇 |
2020年 | 115篇 |
2019年 | 171篇 |
2018年 | 163篇 |
2017年 | 211篇 |
2016年 | 201篇 |
2015年 | 137篇 |
2014年 | 173篇 |
2013年 | 713篇 |
2012年 | 185篇 |
2011年 | 178篇 |
2010年 | 174篇 |
2009年 | 145篇 |
2008年 | 159篇 |
2007年 | 158篇 |
2006年 | 162篇 |
2005年 | 125篇 |
2004年 | 143篇 |
2003年 | 123篇 |
2002年 | 116篇 |
2001年 | 90篇 |
2000年 | 71篇 |
1999年 | 77篇 |
1998年 | 76篇 |
1997年 | 71篇 |
1996年 | 48篇 |
1995年 | 64篇 |
1994年 | 59篇 |
1993年 | 53篇 |
1992年 | 48篇 |
1991年 | 54篇 |
1990年 | 33篇 |
1989年 | 28篇 |
1988年 | 26篇 |
1987年 | 21篇 |
1986年 | 18篇 |
1985年 | 30篇 |
1984年 | 28篇 |
1983年 | 25篇 |
1982年 | 23篇 |
1981年 | 15篇 |
1980年 | 22篇 |
1979年 | 20篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 16篇 |
1975年 | 11篇 |
1974年 | 7篇 |
排序方式: 共有4754条查询结果,搜索用时 15 毫秒
121.
For many continuous distributions, a closed-form expression for their quantiles does not exist. Numerical approximations for their quantiles are developed on a distribution-by-distribution basis. This work develops a general approximation for quantiles using the Taylor expansion. Our method only requires that the distribution has a continuous probability density function and its derivatives can be derived to a certain order (usually 3 or 4). We demonstrate our unified approach by approximating the quantiles of the normal, exponential, and chi-square distributions. The approximation works well for these distributions. 相似文献
122.
Bayesian adaptive dose‐escalation designs for simultaneously estimating the optimal and maximum safe dose based on safety and efficacy
下载免费PDF全文
![点击此处可从《Pharmaceutical statistics》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Wai Yin Yeung Bruno Reigner Ulrich Beyer Cheikh Diack Daniel Sabanés bové Giuseppe Palermo Thomas Jaki 《Pharmaceutical statistics》2017,16(6):396-413
The main purpose of dose‐escalation trials is to identify the dose(s) that is/are safe and efficacious for further investigations in later studies. In this paper, we introduce dose‐escalation designs that incorporate both the dose‐limiting events and dose‐limiting toxicities (DLTs) and indicative responses of efficacy into the procedure. A flexible nonparametric model is used for modelling the continuous efficacy responses while a logistic model is used for the binary DLTs. Escalation decisions are based on the combination of the probabilities of DLTs and expected efficacy through a gain function. On the basis of this setup, we then introduce 2 types of Bayesian adaptive dose‐escalation strategies. The first type of procedures, called “single objective,” aims to identify and recommend a single dose, either the maximum tolerated dose, the highest dose that is considered as safe, or the optimal dose, a safe dose that gives optimum benefit risk. The second type, called “dual objective,” aims to jointly estimate both the maximum tolerated dose and the optimal dose accurately. The recommended doses obtained under these dose‐escalation procedures provide information about the safety and efficacy profile of the novel drug to facilitate later studies. We evaluate different strategies via simulations based on an example constructed from a real trial on patients with type 2 diabetes, and the use of stopping rules is assessed. We find that the nonparametric model estimates the efficacy responses well for different underlying true shapes. The dual‐objective designs give better results in terms of identifying the 2 real target doses compared to the single‐objective designs. 相似文献
123.
Daniel Perkins 《The Australian journal of social issues》2010,45(2):267-287
The last two decades have seen an increasing focus on the activation of individuals receiving welfare benefits. This has entailed an attempt to transform employment assistance and social security systems to make them more employment‐friendly through the development of explicit linkages between social protection policies, labour market participation and labour market programs. At the same time there has been a growing interest in the concept of social inclusion, and social inclusion has been a commonly stated goal of activation programs. However, despite some synergies between these two approaches, in other respects it is not clear that they are always compatible. This paper explores the extent to which activation programs are central to the social inclusion approach and the similarities and differences between these approaches. It then briefly examines the evidence regarding the ability of activation programs to enhance social inclusion. 相似文献
124.
A number of studies have suggested breastfed infants have improved bonding and attachment or cognitive development outcomes.
However, mechanisms by which these differences might develop are poorly understood. We used maternal time use data to examine
whether exclusively breastfeeding mothers spend more time in close interactive behaviors with their infants than mothers who
have commenced or completed weaning. Mothers (188) participating in a time use survey recorded infant feeding activities for
24 h over a 7 day period using an electronic device. Tracking was conducted at 3, 6, and 9 months postpartum. Data was collected
for maternal activities including infant feeding and time spent in emotional care. The mothers of exclusively breastfed infants
aged 3–6 months fed them frequently and total time spent in breastfeeding averaged around 17 h a week. Maternal time spent
in emotional care was also substantial, and found to correlate positively with time spent breastfeeding. Exclusively breastfed
infants received greatest amounts of emotional care from their mother, and exclusively formula fed infants the least. Mixed
fed infants received more emotional care time than formula fed infants, but less than fully breastfed infants. These findings
may help explain the differential cognitive developmental outcomes reported in the medical literature for breastfed and non
breastfed infants. 相似文献
125.
This article takes a first look at the distribution of returns to education for people with disabilities, a particularly disadvantaged group whose labor market performances have not been well studied or documented. Using a nonparametric approach, we uncover significant heterogeneity in the returns to education for these workers, which is drastically masked by conventional parametric methods. Based on these estimates, we construct the Sharpe ratio of human capital investment (taking into account its substantial risk), and our results corroborate the claimed importance of human capital in improving these workers’ wages. Our stochastic dominance tests show that the returns to education for workers with disabilities, as a group, may have been affected more adversely in the most recent recession, relative to their non-disabled counterparts. 相似文献
126.
Mark Cooney 《The British journal of sociology》2009,60(3):473-492
Despite growing awareness of the limitations of group‐level analyses in ethnic studies, research on ethnic conflict has paid virtually no systematic attention to variation at the individual or micro level. Addressing that gap, the present paper draws upon data from interviews conducted with members of two broadly‐defined categories recently arrived in the Republic of Ireland, Muslims and Nigerians. Results indicate that while members of both immigrant categories experience a good deal of ethnic conflict or hostility, such conflict is rarely collective and invariably varies across individuals. The research data are consistent with Donald Black's theory of moralism. Black's theory, based on his theoretical system known as pure sociology, predicts that ethnic hostility increases with the social inferiority and cultural distance of the immigrant, and that higher status immigrants are more assertive in responding to hostility, though they experience less of it (the status paradox). 相似文献
127.
128.
Mark Morey 《Australian Social Work》2013,66(3):51-56
Abstract Limited research has been conducted in relation to the impact of private policing on young people. Research has primarily focused on young people and their use of public space, their use of the street or the policing of working class families and their children. This paper outlines an investigation of young peoples use of public spaces and their experiences of security guards within the greater Sydney metropolitan area of New South Wales. The paper also outlines the experiences of shopping centre managers in relation to the management of young people within their centres. The research found that young people are over policed within public spaces and especially in shopping complexes. Young people are primarily over policed within these spaces because of the perceived fears other groups within the community hold in relation to young people, especially those in groups. 相似文献
129.
130.