全文获取类型
收费全文 | 2096篇 |
免费 | 72篇 |
国内免费 | 13篇 |
专业分类
管理学 | 165篇 |
民族学 | 2篇 |
人口学 | 16篇 |
丛书文集 | 43篇 |
理论方法论 | 11篇 |
综合类 | 422篇 |
社会学 | 33篇 |
统计学 | 1489篇 |
出版年
2024年 | 2篇 |
2023年 | 12篇 |
2022年 | 13篇 |
2021年 | 22篇 |
2020年 | 43篇 |
2019年 | 61篇 |
2018年 | 66篇 |
2017年 | 126篇 |
2016年 | 64篇 |
2015年 | 60篇 |
2014年 | 64篇 |
2013年 | 575篇 |
2012年 | 161篇 |
2011年 | 65篇 |
2010年 | 53篇 |
2009年 | 68篇 |
2008年 | 67篇 |
2007年 | 66篇 |
2006年 | 54篇 |
2005年 | 73篇 |
2004年 | 55篇 |
2003年 | 36篇 |
2002年 | 59篇 |
2001年 | 53篇 |
2000年 | 31篇 |
1999年 | 28篇 |
1998年 | 31篇 |
1997年 | 27篇 |
1996年 | 17篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1993年 | 16篇 |
1992年 | 18篇 |
1991年 | 10篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 5篇 |
1984年 | 8篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1975年 | 3篇 |
排序方式: 共有2181条查询结果,搜索用时 15 毫秒
11.
赵德钧 《绍兴文理学院学报》2002,22(9):9-14
该文给出了一类多元Gauss-Weierstrass算子线性组合加Jacobi权在一致逼近下的正、逆定理和逼近阶的特征刻划 相似文献
12.
Kepher Henry Makambi 《Statistical Methods and Applications》2002,11(1):127-138
The standard hypothesis testing procedure in meta-analysis (or multi-center clinical trials) in the absence of treatment-by-center
interaction relies on approximating the null distribution of the standard test statistic by a standard normal distribution.
For relatively small sample sizes, the standard procedure has been shown by various authors to have poor control of the type
I error probability, leading to too many liberal decisions. In this article, two test procedures are proposed, which rely
on thet—distribution as the reference distribution. A simulation study indicates that the proposed procedures attain significance
levels closer to the nominal level compared with the standard procedure. 相似文献
13.
顾黎诚 《绍兴文理学院学报》2002,(7)
证明了Cusich提出的猜想 (I) .对于任给的n个正整数a1,a2 ,… ,an 总存在一个实数x ,使得‖aix‖ 1n+ 1,i=1,2 ,…n成立 .其中‖x‖表示x到其最近整数的距离 相似文献
14.
SONET (Synchronous Optical NETworks) add-drop multiplexers (ADMs) are the dominant cost factor in the WDM(Wavelength Division Multiplexing)/SONET rings. The number of SONET ADMs required by a set of traffic streams is determined by the routing and wavelength assignment of the traffic streams. Previous works took as input the traffic streams with routings given a priori and developed various heuristics for wavelength assignment to minimize the SONET ADM costs. However, little was known about the performance guarantees of these heuristics. This paper contributes mainly in two aspects. First, in addition to the traffic streams with pre-specified routing, this paper also studies minimizing the ADM requirement by traffic streams without given routings, a problem which is shown to be NP-hard. Several heuristics for integrated routing and wavelength assignment are proposed to minimize the SONET ADM costs. Second, the approximation ratios of those heuristics for wavelength assignment only and those heuristics for integrated routing and wavelength assignment are analyzed. The new Preprocessed Iterative Matching heuristic has the best approximation ratio: at most 3/2. 相似文献
15.
Michael Weba 《Statistical Papers》2002,43(3):445-452
n possibly different success probabilities p
1, p
2, ..., p
n
is frequently approximated by a Poisson distribution with parameter λ = p
1 + p
2 + ... + p
n
. LeCam's bound p
2
1 + p
2
2 + ... + p
n
2 for the total variation distance between both distributions is particularly useful provided the success probabilities are
small.
The paper presents an improved version of LeCam's bound if a generalized d-dimensional Poisson binomial distribution is to be approximated by a compound Poisson distribution.
Received: May 10, 2000; revised version: January 15, 2001 相似文献
16.
郜军才 《石家庄铁道学院学报(社会科学版)》2006,(2):120-123
针对济阳黄河公路大桥钻孔灌注桩桩身长、孔壁易失稳垮塌、单桩混凝土灌注量大等施工难题,通过合理机械选型和控制护壁泥浆配比,取得了良好效果。以4″主墩为例介绍了施工条件及钻孔灌注桩施工技术措施,总结了施工效果。 相似文献
17.
In this paper, the task of determining expected values of sample moments, where the sample members have been selected based on noisy information, is considered. This task is a recurring problem in the theory of evolution strategies. Exact expressions for expected values of sums of products of concomitants of selected order statistics are derived. Then, using Edgeworth and Cornish-Fisher approximations, explicit results that depend on coefficients that can be determined numerically are obtained. While the results are exact only for normal populations, it is shown experimentally that including skewness and kurtosis in the calculations can yield greatly improved results for other distributions. 相似文献
18.
Sample selection in radiocarbon dating 总被引:1,自引:0,他引:1
J. A. Christen & C. E. Buck 《Journal of the Royal Statistical Society. Series C, Applied statistics》1998,47(4):543-557
Archaeologists working on the island of O'ahu, Hawai'i, use radiocarbon dating of samples of organic matter found trapped in fish-pond sediments to help them to learn about the chronology of the construction and use of the aquicultural systems created by the Polynesians. At one particular site, Loko Kuwili, 25 organic samples were obtained and funds were available to date an initial nine. However, on calibration to the calendar scale, the radiocarbon determinations provided date estimates that had very large variances. As a result, major issues of chronology remained unresolved and the archaeologists were faced with the prospect of another expensive programme of radiocarbon dating. This paper presents results of research that tackles the problems associated with selecting samples from those which are still available. Building on considerable recent research that utilizes Markov chain Monte Carlo methods to aid archaeologists in their radiocarbon calibration and interpretation, we adopt the standard Bayesian framework of risk functions, which allows us to assess the optimal samples to be sent for dating. Although rather computer intensive, our algorithms are simple to implement within the Bayesian radiocarbon framework that is already in place and produce results that are capable of direct interpretation by the archaeologists. By dating just three more samples from Loko Kuwili the expected variance on the date of greatest interest could be substantially reduced. 相似文献
19.
Approximation of a density by another density is considered in the case of different dimensionalities of the distributions. The results have been derived by inverting expansions of characteristic functions with the help of matrix techniques. The approximations obtained are all functions of cumulant differences and derivatives of the approximating density. The multivariate Edgeworth expansion follows from the results as a special case. Furthermore, the density functions of the trace and eigenvalues of the sample covariance matrix are approximated by the multivariate normal density and a numerical example is given 相似文献
20.
我国上市公司独立审计质量的博弈模型刻画及其分析 总被引:2,自引:0,他引:2
本文分析了我国上市公司独立审计中会计师事务所、公司管理当局、独立董事、监管部门在审计行为中的博弈关系,应用博弈经济理论研究了在信息不对称条件下四方互动博弈策略的选择,并针对多方博弈的影响因素提出了提高独立审计质量的策略,以期对改进我国上市公司独立审计质量有所裨益. 相似文献