全文获取类型
收费全文 | 22929篇 |
免费 | 297篇 |
专业分类
管理学 | 3161篇 |
民族学 | 147篇 |
人才学 | 1篇 |
人口学 | 3444篇 |
丛书文集 | 78篇 |
教育普及 | 2篇 |
理论方法论 | 1636篇 |
综合类 | 624篇 |
社会学 | 10670篇 |
统计学 | 3463篇 |
出版年
2021年 | 67篇 |
2020年 | 190篇 |
2019年 | 221篇 |
2018年 | 1881篇 |
2017年 | 1989篇 |
2016年 | 1334篇 |
2015年 | 264篇 |
2014年 | 288篇 |
2013年 | 2079篇 |
2012年 | 713篇 |
2011年 | 1445篇 |
2010年 | 1253篇 |
2009年 | 1010篇 |
2008年 | 1074篇 |
2007年 | 1257篇 |
2006年 | 216篇 |
2005年 | 571篇 |
2004年 | 540篇 |
2003年 | 473篇 |
2002年 | 350篇 |
2001年 | 318篇 |
2000年 | 307篇 |
1999年 | 314篇 |
1998年 | 209篇 |
1997年 | 204篇 |
1996年 | 241篇 |
1995年 | 188篇 |
1994年 | 204篇 |
1993年 | 177篇 |
1992年 | 236篇 |
1991年 | 232篇 |
1990年 | 211篇 |
1989年 | 219篇 |
1988年 | 204篇 |
1987年 | 185篇 |
1986年 | 189篇 |
1985年 | 174篇 |
1984年 | 207篇 |
1983年 | 200篇 |
1982年 | 165篇 |
1981年 | 137篇 |
1980年 | 139篇 |
1979年 | 166篇 |
1978年 | 136篇 |
1977年 | 119篇 |
1976年 | 102篇 |
1975年 | 101篇 |
1974年 | 95篇 |
1973年 | 93篇 |
1971年 | 64篇 |
排序方式: 共有10000条查询结果,搜索用时 218 毫秒
81.
We employ vector autoregressive techniques to determine the current state of the labor queue. Unemployment rate differentials
have narrowed in recent years, potentially due to a change in the queue ordering, though a tight labor market and a stable
queue would yield similar results. We find no evidence that the queue ordering has changed, which brings into question the
resiliency of gains made by minority groups. We employ the same techniques to reveal the state of the queue across geographic
regions and find that substantial differences exist across regions, implying variation in the relative labor force status
of demographic groups. 相似文献
82.
土木工程类复合型执业人才培养的研究与实践 总被引:1,自引:0,他引:1
根据复合型执业人才培养模式的要求,对土木工程专业理论课程教学内容进行合并、增删、优化组合;在实践教学环节方面,安排大四学生在施工现场实践近1年,由项目经理、工程监理和发包方驻地工程师进行综合指导。理论与实践紧密结合的复合型执业人才培养的改革实践获得了极好的效果。 相似文献
83.
Generalized additive models for location, scale and shape 总被引:10,自引:0,他引:10
R. A. Rigby D. M. Stasinopoulos 《Journal of the Royal Statistical Society. Series C, Applied statistics》2005,54(3):507-554
Summary. A general class of statistical models for a univariate response variable is presented which we call the generalized additive model for location, scale and shape (GAMLSS). The model assumes independent observations of the response variable y given the parameters, the explanatory variables and the values of the random effects. The distribution for the response variable in the GAMLSS can be selected from a very general family of distributions including highly skew or kurtotic continuous and discrete distributions. The systematic part of the model is expanded to allow modelling not only of the mean (or location) but also of the other parameters of the distribution of y , as parametric and/or additive nonparametric (smooth) functions of explanatory variables and/or random-effects terms. Maximum (penalized) likelihood estimation is used to fit the (non)parametric models. A Newton–Raphson or Fisher scoring algorithm is used to maximize the (penalized) likelihood. The additive terms in the model are fitted by using a backfitting algorithm. Censored data are easily incorporated into the framework. Five data sets from different fields of application are analysed to emphasize the generality of the GAMLSS class of models. 相似文献
84.
Point processes are the stochastic models most suitable for describing physical phenomena that appear at irregularly spaced
times, such as the earthquakes. These processes are uniquely characterized by their conditional intensity, that is, by the
probability that an event will occur in the infinitesimal interval (t, t+Δt), given the history of the process up tot. The seismic phenomenon displays different behaviours on different time and size scales; in particular, the occurrence of
destructive shocks over some centuries in a seismogenic region may be explained by the elastic rebound theory. This theory
has inspired the so-called stress release models: their conditional intensity translates the idea that an earthquake produces
a sudden decrease in the amount of strain accumulated gradually over time along a fault, and the subsequent event occurs when
the stress exceeds the strength of the medium. This study has a double objective: the formulation of these models in the Bayesian
framework, and the assignment to each event of a mark, that is its magnitude, modelled through a distribution that depends
at timet on the stress level accumulated up to that instant. The resulting parameter space is constrained and dependent on the data,
complicating Bayesian computation and analysis. We have resorted to Monte Carlo methods to solve these problems. 相似文献
85.
Christian P. Robert Xiao-Li Meng Jesper Møller Jeffrey S Rosenthal C Jennison M. A Hurn F Al-Awadhi Peter McCullagh Christophe Andrieu Arnaud Doucet Petros Dellaportas Ioulia Papageorgiou Ricardo S Ehlers Elena A Erosheva Stephen E Fienberg Jonathan J Forster Roger C Gill Nial Friel Peter Green David Hastie R King Hans R Künsch N. A. Lazar C Osinski 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2003,65(1):39-55
86.
The Measurement of Multidimensional Poverty 总被引:14,自引:0,他引:14
Many authors have insisted on the necessity of defining poverty as a multidimensional concept rather than relying on income or consumption expenditures per capita. Yet, not much has actually been done to include the various dimensions of deprivation into the practical definition and measurement of poverty. Existing attempts along that direction consist of aggregating various attributes into a single index through some arbitrary function and defining a poverty line and associated poverty measures on the basis of that index. This is merely redefining more generally the concept of poverty, which then essentially remains a one dimensional concept. The present paper suggests that an alternative way to take into account the multi-dimensionality of poverty is to specify a poverty line for each dimension of poverty and to consider that a person is poor if he/she falls below at least one of these various lines. The paper then explores how to combine these various poverty lines and associated one-dimensional gaps into multidimensional poverty measures. An application of these measures to the rural population in Brazil is also given with poverty defined on income and education. 相似文献
87.
Michael S. Rendall Ryan Admiraal Alessandra DeRose Paola DiGiulio Mark S. Handcock Filomena Racioppi 《Statistical Methods and Applications》2008,17(4):519-539
In non-experimental research, data on the same population process may be collected simultaneously by more than one instrument.
For example, in the present application, two sample surveys and a population birth registration system all collect observations
on first births by age and year, while the two surveys additionally collect information on women’s education. To make maximum
use of the three data sources, the survey data are pooled and the population data introduced as constraints in a logistic
regression equation. Reductions in standard errors about the age and birth-cohort parameters of the regression equation in
the order of three-quarters are obtained by introducing the population data as constraints. A halving of the standard errors
about the education parameters is achieved by pooling observations from the larger survey dataset with those from the smaller
survey. The percentage reduction in the standard errors through imposing population constraints is independent of the total
survey sample size. 相似文献
88.
89.
90.