全文获取类型
收费全文 | 17664篇 |
免费 | 717篇 |
国内免费 | 239篇 |
专业分类
管理学 | 2306篇 |
劳动科学 | 2篇 |
民族学 | 64篇 |
人才学 | 4篇 |
人口学 | 335篇 |
丛书文集 | 895篇 |
理论方法论 | 397篇 |
综合类 | 8612篇 |
社会学 | 543篇 |
统计学 | 5462篇 |
出版年
2024年 | 26篇 |
2023年 | 148篇 |
2022年 | 256篇 |
2021年 | 262篇 |
2020年 | 393篇 |
2019年 | 496篇 |
2018年 | 567篇 |
2017年 | 703篇 |
2016年 | 618篇 |
2015年 | 633篇 |
2014年 | 988篇 |
2013年 | 2239篇 |
2012年 | 1296篇 |
2011年 | 1163篇 |
2010年 | 970篇 |
2009年 | 934篇 |
2008年 | 1015篇 |
2007年 | 986篇 |
2006年 | 952篇 |
2005年 | 771篇 |
2004年 | 648篇 |
2003年 | 540篇 |
2002年 | 478篇 |
2001年 | 416篇 |
2000年 | 264篇 |
1999年 | 198篇 |
1998年 | 104篇 |
1997年 | 112篇 |
1996年 | 77篇 |
1995年 | 66篇 |
1994年 | 47篇 |
1993年 | 43篇 |
1992年 | 42篇 |
1991年 | 41篇 |
1990年 | 24篇 |
1989年 | 22篇 |
1988年 | 19篇 |
1987年 | 10篇 |
1986年 | 7篇 |
1985年 | 13篇 |
1984年 | 8篇 |
1983年 | 9篇 |
1982年 | 5篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
利用扩展的线性支出系统模型(ELES),采用最小二乘法估计计算了我国农村居民的短期医疗服务需求价格弹性。研究结果表明:农村居民的短期医疗服务需求价格缺乏弹性。由于农村居民的短期医疗服务需求价格缺乏弹性,加上我国目前医疗体制存在的以药养医和医疗机构的逐利行为以及医疗市场缺乏有效的监管等问题,导致农村居民看病难、看病贵。解决这个问题,需要国家增加对卫生领域的投入,降低农民看病时自费的比例,增强卫生市场的竞争性,适当使医疗卫生资源向农村地区倾斜,并逐渐把医疗机构办成非盈利机构。 相似文献
52.
Backfitting Random Varying-Coefficient Models with Time-Dependent Smoothing Covariates 总被引:1,自引:0,他引:1
Abstract. In this paper, we propose a random varying-coefficient model for longitudinal data. This model is different from the standard varying-coefficient model in the sense that the time-varying coefficients are assumed to be subject-specific, and can be considered as realizations of stochastic processes. This modelling strategy allows us to employ powerful mixed-effects modelling techniques to efficiently incorporate the within-subject and between-subject variations in the estimators of time-varying coefficients. Thus, the subject-specific feature of longitudinal data is effectively considered in the proposed model. A backfitting algorithm is proposed to estimate the coefficient functions. Simulation studies show that the proposed estimation methods are more efficient in finite-sample performance compared with the standard local least squares method. An application to an AIDS clinical study is presented to illustrate the proposed methodologies. 相似文献
53.
对基础研究投入问题的思考 总被引:3,自引:0,他引:3
夏光育 《郑州航空工业管理学院学报(社会科学版)》2007,26(3):190-192
文章首先从公共财政的角度对基础研究的投入进行分析,其次从布什和斯托克斯的科研模式角度对基础研究的投入进行分析。在此基础上对加大我国基础研究的投入提出了相关建议。 相似文献
54.
The authors study the local influence of observations in multilevel regression models. To this end, they perturb simultaneously the variances, responses and design matrix. To measure the local change caused by these perturbations, they use generalized Cook statistics for the fixed and random parameter estimates. Closed form local influence measures also allow them to assess the joint influence of various observations. They suggest a simple computation method and illustrate their results using two examples. 相似文献
55.
Yosihiko Ogata Koichi Katsura Masaharu Tanemura 《Journal of the Royal Statistical Society. Series C, Applied statistics》2003,52(4):499-509
Summary. Earthquake intensities are modelled as a function of previous activity whose specific form is based on established empirical laws in seismology, but whose parameter values can vary from place to place. This model is used for characterizing regional features of seismic activities in and around Japan, and also for exploring regions where the actual seismicity rate systematically deviates from that of the modelled rate. 相似文献
56.
肖升 《湖南人文科技学院学报》2004,(2):41-43
关系数据模型是基于记录的基本数据模型;面向对象数据模型是基于对象的基本数据模型;两种数据模型在某种程度上应存在相互映射和相互转变的可能性,它们的相互映射和相互转变将使关系数据库和面向对象数据库之间的转变成为可能。 相似文献
57.
Bias Correction in the Dynamic Panel Data Model with a Nonscalar Disturbance Covariance Matrix 总被引:1,自引:0,他引:1
Maurice J. G. Bun 《Econometric Reviews》2003,22(1):29-58
Approximation formulae are developed for the bias of ordinary and generalized Least Squares Dummy Variable (LSDV) estimators in dynamic panel data models. Results from Kiviet [Kiviet, J. F. (1995), on bias, inconsistency, and efficiency of various estimators in dynamic panel data models, J. Econometrics68:53-78; Kiviet, J. F. (1999), Expectations of expansions for estimators in a dynamic panel data model: some results for weakly exogenous regressors, In: Hsiao, C., Lahiri, K., Lee, L-F., Pesaran, M. H., eds., Analysis of Panels and Limited Dependent Variables, Cambridge: Cambridge University Press, pp. 199-225] are extended to higher-order dynamic panel data models with general covariance structure. The focus is on estimation of both short- and long-run coefficients. The results show that proper modelling of the disturbance covariance structure is indispensable. The bias approximations are used to construct bias corrected estimators which are then applied to quarterly data from 14 European Union countries. Money demand functions for M1, M2 and M3 are estimated for the EU area as a whole for the period 1991: I-1995: IV. Significant spillovers between countries are found reflecting the dependence of domestic money demand on foreign developments. The empirical results show that in general plausible long-run effects are obtained by the bias corrected estimators. Moreover, finite sample bias, although of moderate magnitude, is present underlining the importance of more refined estimation techniques. Also the efficiency gains by exploiting the heteroscedasticity and cross-correlation patterns between countries are sometimes considerable. 相似文献
58.
名词性复合词的意义建构是一个看似简单,实际上非常复杂的过程。传统语法把这一意义建构过程简单化,认为名词性复合词的意义等于各组成部分名词的意义总和。转换生成语言学家 意义特征理论学家也都提出了各自的理论解释,但都有很大的缺陷。概念合成语言学理论对名词性复合词的意义建构做出了比较完整的理论解释,但也有待于进一步的改进。 相似文献
59.
肖柯则 《内蒙古工业大学学报》1996,15(3):7-12
等温淬火球墨铸铁的机械性能与其声学性能相关。本文将两种碳当量球铁在845,899和945℃温度进行奥氏体处理,在260,316和371℃温度进行等温淬火得到证实。声学性能测量包括共振频率,声速和内耗。由共振频率转换成动态模量表示出这种关系可以用来预报球墨铸铁不同热处理条件下的机械性能。 相似文献
60.
John S. J. HSU 《Revue canadienne de statistique》1995,23(4):399-410
This paper presents a new Laplacian approximation to the posterior density of η = g(θ). It has a simpler analytical form than that described by Leonard et al. (1989). The approximation derived by Leonard et al. requires a conditional information matrix Rη to be positive definite for every fixed η. However, in many cases, not all Rη are positive definite. In such cases, the computations of their approximations fail, since the approximation cannot be normalized. However, the new approximation may be modified so that the corresponding conditional information matrix can be made positive definite for every fixed η. In addition, a Bayesian procedure for contingency-table model checking is provided. An example of cross-classification between the educational level of a wife and fertility-planning status of couples is used for explanation. Various Laplacian approximations are computed and compared in this example and in an example of public school expenditures in the context of Bayesian analysis of the multiparameter Fisher-Behrens problem. 相似文献