全文获取类型
收费全文 | 3183篇 |
免费 | 114篇 |
国内免费 | 38篇 |
专业分类
管理学 | 257篇 |
劳动科学 | 2篇 |
民族学 | 18篇 |
人口学 | 177篇 |
丛书文集 | 158篇 |
理论方法论 | 102篇 |
综合类 | 1503篇 |
社会学 | 61篇 |
统计学 | 1057篇 |
出版年
2024年 | 2篇 |
2023年 | 14篇 |
2022年 | 25篇 |
2021年 | 34篇 |
2020年 | 66篇 |
2019年 | 60篇 |
2018年 | 91篇 |
2017年 | 125篇 |
2016年 | 88篇 |
2015年 | 74篇 |
2014年 | 144篇 |
2013年 | 444篇 |
2012年 | 210篇 |
2011年 | 188篇 |
2010年 | 156篇 |
2009年 | 163篇 |
2008年 | 184篇 |
2007年 | 199篇 |
2006年 | 171篇 |
2005年 | 178篇 |
2004年 | 126篇 |
2003年 | 121篇 |
2002年 | 105篇 |
2001年 | 83篇 |
2000年 | 58篇 |
1999年 | 39篇 |
1998年 | 29篇 |
1997年 | 31篇 |
1996年 | 21篇 |
1995年 | 27篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 11篇 |
1991年 | 13篇 |
1990年 | 8篇 |
1989年 | 4篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 3篇 |
1982年 | 4篇 |
1979年 | 1篇 |
排序方式: 共有3335条查询结果,搜索用时 407 毫秒
181.
182.
The traditional Cobb–Douglas production function uses the compact mathematical form to describe the relationship between the production results and production factors in the production technology process. However, in macro-economic production, multi-structured production exists universally. In order to better demonstrate such input–output relation, a composite production function model is proposed in this article. In aspect of model parameter estimation, artificial fish swarm algorithm is applied. The algorithm has satisfactory performance in overcoming local extreme value and acquiring global extreme value. Moreover, realization of the algorithm does not need the gradient value of the objective function. For this reason, it is adaptive to searching space. Through the improved artificial fish swarm algorithm, convergence rate and precision are both considerably improved. In aspect of model application, the composite production function model is mainly used to calculate economic growth factor contribution rate. In this article, a relatively more accurate calculating method is proposed. In the end, empirical analysis on economic growth contribution rate of China is implemented. 相似文献
183.
Adriano K. Suzuki Gladys D. C. Barriga Francisco Louzada Vicente G. Cancho 《统计学通讯:理论与方法》2017,46(6):3080-3098
In this paper we propose a general cure rate aging model. Our approach enables different underlying activation mechanisms which lead to the event of interest. The number of competing causes of the event of interest is assumed to follow a logarithmic distribution. The model is parameterized in terms of the cured fraction which is then linked to covariates. We explore the use of Markov chain Monte Carlo methods to develop a Bayesian analysis for the proposed model. Moreover, some discussions on the model selection to compare the fitted models are given, as well as case deletion influence diagnostics are developed for the joint posterior distribution based on the ψ-divergence, which has several divergence measures as particular cases, such as the Kullback–Leibler (K-L), J-distance, L1 norm, and χ2-square divergence measures. Simulation studies are performed and experimental results are illustrated based on a real malignant melanoma data. 相似文献
184.
In this article, based on generalized order statistics from a family of proportional hazard rate model, we use a statistical test to generate a class of preliminary test estimators and shrinkage preliminary test estimators for the proportionality parameter. These estimators are compared under Pitman measure of closeness (PMC) as well as MSE criteria. Although the PMC suffers from non transitivity, in the first class of estimators, it has the transitivity property and we obtain the Pitman-closest estimator. Analytical and graphical methods are used to show the range of parameter in which preliminary test and shrinkage preliminary test estimators perform better than their competitor estimators. Results reveal that when the prior information is not too far from its real value, the proposed estimators are superior based on both mentioned criteria. 相似文献
185.
Tang Qingguo 《统计学通讯:理论与方法》2017,46(8):3782-3800
This paper studies M-estimation in functional linear regression in which the dependent variable is scalar while the covariate is a function. An estimator for the slope function is obtained based on the functional principal component basis. The global convergence rate of the M-estimator of unknown slope function is established. The convergence rate of the mean-squared prediction error for the proposed estimators is also established. Monte Carlo simulation studies are conducted to examine the finite-sample performance of the proposed procedure. Finally, the proposed method is applied to analyze the Berkeley growth data. 相似文献
186.
Amarjit Kundu 《统计学通讯:理论与方法》2017,46(9):4163-4180
Recently, the concept of cumulative residual entropy (CRE) has been studied by many researchers in higher dimensions. In this article, we extend the definition of (dynamic) cumulative past entropy (DCPE), a dual measure of (dynamic) CRE, to bivariate setup and obtain some of its properties including bounds. We also look into the problem of extending DCPE for conditionally specified models. Several properties, including monotonicity, and bounds of DCPE are obtained for conditional distributions. It is shown that the proposed measure uniquely determines the distribution function. Moreover, we also propose a stochastic order based on this measure. 相似文献
187.
In this paper, the researchers attempt to introduce a new generalization of the Weibull-geometric distribution. The failure rate function of the new model is found to be increasing, decreasing, upside-down bathtub, and bathtub-shaped. The researchers obtained the new model by compounding Weibull distribution and discrete generalized exponential distribution of a second type, which is a generalization of the geometric distribution. The new introduced model contains some previously known lifetime distributions as well as a new one. Some basic distributional properties and moments of the new model are discussed. Estimation of the parameters is illustrated and the model with two known real data sets is examined. 相似文献
188.
Sexual abuse has physiological and emotional implications. The purpose of this study is to evaluate the neurobiological sequels of childhood sexual trauma by monitoring physiological variables among sexually abused girls and women compared to controls. We assessed posttrauma and traumatic life events of 35 females sexually abused in their childhood (age range 7–51 years) and 25 control females (age range 7–54 years). Electroencephalography, frontalis electromyography, electrodermal activity, and heart rate parameters were recorded while watching sets of pictures representing neutral and trauma-suggestive stimuli. A minority of participants met the Diagnostic and Statistical Manual of Mental Disorders criteria for post-traumatic stress disorder. Abused females displayed significant elevations in heart rate, electromyography, and electroencephalography while viewing allusive stimuli and elevated heart rate while viewing neutral stimuli. The dysfunctional regulation of the physiological stress system associated with child sexual abuse may endanger the victims with various stress and anxiety disorders. 相似文献
189.
文章根据陕西省历次人口普查、部分人口抽样调查资料及公安、教育、计生统计报表数据,时全省出生人口性别失衡程度、女婴缺失数量和分因素贡献率等几个问题进行定量分析,并对出生人口性别比综合治理和科学决策提出建议。 相似文献
190.
针对相干光正交频分复用(coherent optical orthogonal frequency division multiplexing,CO-OFDM)系统中相位噪声引起的载波间干扰(inter-carrier interference,ICI)问题,提出了一种基于线性预处理的新判决反馈相位噪声抑制算法。该新算法改进了线性预处理部分,利用循环前缀与OFDM符号固有的相关性,在时域进行简单的线性组合运算,充分利用了OFDM符号中冗余信息。仿真分析表明,在激光器线宽为200 kHz且误码率(bit error rate, BER)为10-4时,与判决反馈相位噪声抑制算法和一次迭代的判决反馈相位噪声抑制算法相比,该新算法BER曲线的信噪比(signal to noise ratio,SNR)分别改善了3 dB和1 dB,有效地降低由ICI引起的错误平层。 相似文献