全文获取类型
收费全文 | 15413篇 |
免费 | 372篇 |
国内免费 | 2篇 |
学科分类
社会科学 | 15787篇 |
出版年
2023年 | 89篇 |
2020年 | 218篇 |
2019年 | 333篇 |
2018年 | 350篇 |
2017年 | 533篇 |
2016年 | 387篇 |
2015年 | 284篇 |
2014年 | 369篇 |
2013年 | 2869篇 |
2012年 | 465篇 |
2011年 | 448篇 |
2010年 | 344篇 |
2009年 | 331篇 |
2008年 | 408篇 |
2007年 | 391篇 |
2006年 | 367篇 |
2005年 | 532篇 |
2004年 | 350篇 |
2003年 | 286篇 |
2002年 | 304篇 |
2001年 | 372篇 |
2000年 | 351篇 |
1999年 | 315篇 |
1998年 | 255篇 |
1997年 | 235篇 |
1996年 | 216篇 |
1995年 | 185篇 |
1994年 | 209篇 |
1993年 | 207篇 |
1992年 | 237篇 |
1991年 | 237篇 |
1990年 | 225篇 |
1989年 | 202篇 |
1988年 | 180篇 |
1987年 | 195篇 |
1986年 | 183篇 |
1985年 | 164篇 |
1984年 | 195篇 |
1983年 | 161篇 |
1982年 | 154篇 |
1981年 | 104篇 |
1980年 | 145篇 |
1979年 | 156篇 |
1978年 | 112篇 |
1977年 | 122篇 |
1976年 | 102篇 |
1975年 | 124篇 |
1974年 | 97篇 |
1972年 | 80篇 |
1971年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Dennis Wagenaar Tiaravanni Hermawan Marc J. C. van den Homberg Jeroen C. J. H. Aerts Heidi Kreibich Hans de Moel Laurens M. Bouwer 《Risk analysis》2021,41(1):37-55
Damage models for natural hazards are used for decision making on reducing and transferring risk. The damage estimates from these models depend on many variables and their complex sometimes nonlinear relationships with the damage. In recent years, data‐driven modeling techniques have been used to capture those relationships. The available data to build such models are often limited. Therefore, in practice it is usually necessary to transfer models to a different context. In this article, we show that this implies the samples used to build the model are often not fully representative for the situation where they need to be applied on, which leads to a “sample selection bias.” In this article, we enhance data‐driven damage models by applying methods, not previously applied to damage modeling, to correct for this bias before the machine learning (ML) models are trained. We demonstrate this with case studies on flooding in Europe, and typhoon wind damage in the Philippines. Two sample selection bias correction methods from the ML literature are applied and one of these methods is also adjusted to our problem. These three methods are combined with stochastic generation of synthetic damage data. We demonstrate that for both case studies, the sample selection bias correction techniques reduce model errors, especially for the mean bias error this reduction can be larger than 30%. The novel combination with stochastic data generation seems to enhance these techniques. This shows that sample selection bias correction methods are beneficial for damage model transfer. 相似文献
2.
In this article, we propose a novel approach for testing the equality of two log-normal populations using a computational approach test (CAT) that does not require explicit knowledge of the sampling distribution of the test statistic. Simulation studies demonstrate that the proposed approach can perform hypothesis testing with satisfying actual size even at small sample sizes. Overall, it is superior to other existing methods. Also, a CAT is proposed for testing about reliability of two log-normal populations when the means are the same. Simulations show that the actual size of this new approach is close to nominal level and better than the score test. At the end, the proposed methods are illustrated using two examples. 相似文献
3.
Cancho Vicente G. Macera Márcia A. C. Suzuki Adriano K. Louzada Francisco Zavaleta Katherine E. C. 《Lifetime data analysis》2020,26(2):221-244
Lifetime Data Analysis - Frailty models are generally used to model heterogeneity between the individuals. The distribution of the frailty variable is often assumed to be continuous. However, there... 相似文献
4.
Researchers have been developing various extensions and modified forms of the Weibull distribution to enhance its capability for modeling and fitting different data sets. In this note, we investigate the potential usefulness of the new modification to the standard Weibull distribution called odd Weibull distribution in income economic inequality studies. Some mathematical and statistical properties of this model are proposed. We obtain explicit expressions for the first incomplete moment, quantile function, Lorenz and Zenga curves and related inequality indices. In addition to the well-known stochastic order based on Lorenz curve, the stochastic order based on Zenga curve is considered. Since the new generalized Weibull distribution seems to be suitable to model wealth, financial, actuarial and especially income distributions, these findings are fundamental in the understanding of how parameter values are related to inequality. Also, the estimation of parameters by maximum likelihood and moment methods is discussed. Finally, this distribution has been fitted to United States and Austrian income data sets and has been found to fit remarkably well in compare with the other widely used income models. 相似文献
5.
Cathy W. S. Chen Hong Than-Thi Mike K. P. So 《Journal of Statistical Computation and Simulation》2019,89(2):191-210
This paper proposes a new hysteretic vector autoregressive (HVAR) model in which the regime switching may be delayed when the hysteresis variable lies in a hysteresis zone. We integrate an adapted multivariate Student-t distribution from amending the scale mixtures of normal distributions. This HVAR model allows for a higher degree of flexibility in the degrees of freedom for each time series. We use the proposed model to test for a causal relationship between any two target time series. Using posterior odds ratios, we overcome the limitations of the classical approach to multiple testing. Both simulated and real examples herein help illustrate the suggested methods. We apply the proposed HVAR model to investigate the causal relationship between the quarterly growth rates of gross domestic product of United Kingdom and United States. Moreover, we check the pairwise lagged dependence of daily PM2.5 levels in three districts of Taipei. 相似文献
6.
Bartlett correction constitutes one of the attractive features of empirical likelihood because it enables the construction of confidence regions for parameters with improved coverage probabilities. We study the Bartlett correction of spatial frequency domain empirical likelihood (SFDEL) based on general spectral estimating functions for regularly spaced spatial data. This general formulation can be applied to testing and estimation problems in spatial analysis, for example testing covariance isotropy, testing covariance separability as well as estimating the parameters of spatial covariance models. We show that the SFDEL is Bartlett correctable. In particular, the improvement in coverage accuracies of the Bartlett‐corrected confidence regions depends on the underlying spatial structures. The Canadian Journal of Statistics 47: 455–472; 2019 © 2019 Statistical Society of Canada 相似文献
7.
8.
9.
Mary K. Fagan 《Infancy》2019,24(3):338-355
Infant development has rarely been informed by the behavior of infants with sensory differences despite increasing recognition that infant behavior itself creates sensory learning opportunities. The purpose of this study of object exploration was to compare the behavior of hearing and deaf infants, with and without cochlear implants, in order to identify the effects of profound sensorineural hearing loss on infant exploration before cochlear implantation, the behavioral effects of access to auditory feedback after cochlear implantation, and the sensory motivation for exploration behaviors performed by hearing infants as well. The results showed that 9‐month‐old deaf infants explored objects as often as hearing infants but they used systematically different approaches and less variation before compared to after cochlear implantation. Potential associations between these early experiences and later learning are discussed in the context of embodied developmental theory, comparative studies, and research with adults. The data call for increased recognition of the active sensorimotor nature of infant learning and future research that investigates differences in sensorimotor experience as potential mechanisms in later learning and sequential memory development. 相似文献
10.
More than 100 pieces of anti-lesbian, gay, bisexual, transgender (LGBT) legislation are active in 2018. In this current political climate of “conscience clause” legislation, counselor educators and supervisors are poised to adopt more holistic practices in assessing and evaluating student and supervisee readiness to work with LGBT queer (Q) clients. The purpose of this article is to present a dispositional framework for assessment and evaluation and introduce the flexibility, integrity, awareness, stability, compassion, and openness (FIASCO) rubric of professional counseling dispositions. Two court cases, Keeton v. Anderson-Wiley and Ward v. Wilbanks, are used as case examples for applying the FIASCO rubric to situations involving LGBTQ clients. 相似文献