全文获取类型
收费全文 | 8425篇 |
免费 | 161篇 |
国内免费 | 38篇 |
专业分类
管理学 | 388篇 |
民族学 | 28篇 |
人口学 | 150篇 |
丛书文集 | 269篇 |
理论方法论 | 126篇 |
综合类 | 2045篇 |
社会学 | 83篇 |
统计学 | 5535篇 |
出版年
2024年 | 6篇 |
2023年 | 30篇 |
2022年 | 65篇 |
2021年 | 66篇 |
2020年 | 125篇 |
2019年 | 235篇 |
2018年 | 266篇 |
2017年 | 515篇 |
2016年 | 179篇 |
2015年 | 196篇 |
2014年 | 285篇 |
2013年 | 2357篇 |
2012年 | 634篇 |
2011年 | 334篇 |
2010年 | 261篇 |
2009年 | 279篇 |
2008年 | 300篇 |
2007年 | 292篇 |
2006年 | 245篇 |
2005年 | 285篇 |
2004年 | 223篇 |
2003年 | 211篇 |
2002年 | 204篇 |
2001年 | 190篇 |
2000年 | 164篇 |
1999年 | 98篇 |
1998年 | 80篇 |
1997年 | 66篇 |
1996年 | 50篇 |
1995年 | 39篇 |
1994年 | 35篇 |
1993年 | 41篇 |
1992年 | 34篇 |
1991年 | 31篇 |
1990年 | 29篇 |
1989年 | 27篇 |
1988年 | 18篇 |
1987年 | 20篇 |
1986年 | 10篇 |
1985年 | 14篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 9篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 6篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 5篇 |
排序方式: 共有8624条查询结果,搜索用时 343 毫秒
21.
针对串联型稳压器,设计了一种应用于串联型稳压器具有自建基准的新型误差放大电路。该电路具有构思巧妙,结构优化,易于集成及较高的开环增益,共模抑制比及交流特性的优点。通过验证,实测数据与仿真结果基本一致。 相似文献
22.
杨曼英 《湖南人文科技学院学报》2004,(2):78-79
通过定义、定理、正反对比的例题论述了函数列收敛、一致收敛、内闭一致收敛及其之间的关系与差异。 相似文献
23.
Peter Hall Qiwei Yao 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2003,65(2):425-442
Summary. We develop a general methodology for tilting time series data. Attention is focused on a large class of regression problems, where errors are expressed through autoregressive processes. The class has a range of important applications and in the context of our work may be used to illustrate the application of tilting methods to interval estimation in regression, robust statistical inference and estimation subject to constraints. The method can be viewed as 'empirical likelihood with nuisance parameters'. 相似文献
24.
Diagnostics for dependence within time series extremes 总被引:1,自引:0,他引:1
Anthony W. Ledford Jonathan A. Tawn 《Journal of the Royal Statistical Society. Series B, Statistical methodology》2003,65(2):521-543
Summary. The analysis of extreme values within a stationary time series entails various assumptions concerning its long- and short-range dependence. We present a range of new diagnostic tools for assessing whether these assumptions are appropriate and for identifying structure within extreme events. These tools are based on tail characteristics of joint survivor functions but can be implemented by using existing estimation methods for extremes of univariate independent and identically distributed variables. Our diagnostic aids are illustrated through theoretical examples, simulation studies and by application to rainfall and exchange rate data. On the basis of these diagnostics we can explain characteristics that are found in the observed extreme events of these series and also gain insight into the properties of events that are more extreme than those observed. 相似文献
25.
We propose some estimators of noncentrality parameters which improve upon usual unbiased estimators under quadratic loss. The distributions we consider are the noncentral chi-square and the noncentral F. However, we give more general results for the family of elliptically contoured distributions and propose a robust dominating estimator. 相似文献
26.
Impacts of complex emergencies or relief interventions have often been evaluated by absolute mortality compared to international standardized mortality rates. A better evaluation would be to compare with local baseline mortality of the affected populations. A projection of population-based survival data into time of emergency or intervention based on information from before the emergency may create a local baseline reference. We find a log-transformed Gaussian time series model where standard errors of the estimated rates are included in the variance to have the best forecasting capacity. However, if time-at-risk during the forecasted period is known then forecasting might be done using a Poisson time series model with overdispersion. Whatever, the standard error of the estimated rates must be included in the variance of the model either in an additive form in a Gaussian model or in a multiplicative form by overdispersion in a Poisson model. Data on which the forecasting is based must be modelled carefully concerning not only calendar-time trends but also periods with excessive frequency of events (epidemics) and seasonal variations to eliminate residual autocorrelation and to make a proper reference for comparison, reflecting changes over time during the emergency. Hence, when modelled properly it is possible to predict a reference to an emergency-affected population based on local conditions. We predicted childhood mortality during the war in Guinea-Bissau 1998-1999. We found an increased mortality in the first half-year of the war and a mortality corresponding to the expected one in the last half-year of the war. 相似文献
27.
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
28.
29.
Discrete time modelling of disease incidence time series by using Markov chain Monte Carlo methods 总被引:1,自引:0,他引:1
Alexander Morton Bärbel F. Finkenstädt 《Journal of the Royal Statistical Society. Series C, Applied statistics》2005,54(3):575-594
Summary. A stochastic discrete time version of the susceptible–infected–recovered model for infectious diseases is developed. Disease is transmitted within and between communities when infected and susceptible individuals interact. Markov chain Monte Carlo methods are used to make inference about these unobserved populations and the unknown parameters of interest. The algorithm is designed specifically for modelling time series of reported measles cases although it can be adapted for other infectious diseases with permanent immunity. The application to observed measles incidence series motivates extensions to incorporate age structure as well as spatial epidemic coupling between communities. 相似文献
30.
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