全文获取类型
收费全文 | 1978篇 |
免费 | 49篇 |
国内免费 | 9篇 |
专业分类
管理学 | 151篇 |
民族学 | 3篇 |
人口学 | 11篇 |
丛书文集 | 28篇 |
理论方法论 | 11篇 |
综合类 | 319篇 |
社会学 | 65篇 |
统计学 | 1448篇 |
出版年
2024年 | 2篇 |
2023年 | 14篇 |
2022年 | 13篇 |
2021年 | 17篇 |
2020年 | 42篇 |
2019年 | 78篇 |
2018年 | 82篇 |
2017年 | 136篇 |
2016年 | 67篇 |
2015年 | 49篇 |
2014年 | 77篇 |
2013年 | 471篇 |
2012年 | 139篇 |
2011年 | 52篇 |
2010年 | 72篇 |
2009年 | 60篇 |
2008年 | 57篇 |
2007年 | 65篇 |
2006年 | 58篇 |
2005年 | 50篇 |
2004年 | 34篇 |
2003年 | 44篇 |
2002年 | 52篇 |
2001年 | 46篇 |
2000年 | 30篇 |
1999年 | 29篇 |
1998年 | 29篇 |
1997年 | 32篇 |
1996年 | 19篇 |
1995年 | 18篇 |
1994年 | 10篇 |
1993年 | 13篇 |
1992年 | 14篇 |
1991年 | 5篇 |
1990年 | 12篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 6篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 2篇 |
排序方式: 共有2036条查询结果,搜索用时 359 毫秒
41.
《Journal of Statistical Computation and Simulation》2012,82(2):324-334
When we are given only a transform such as the moment-generating function of a distribution, it is rare that we can efficiently simulate random variables. Possible approaches such as the inverse transform using numerical inversion of the transform are computationally very expensive. However, the saddlepoint approximation is known to be exact for the Normal, Gamma, and inverse Gaussian distribution and remarkably accurate for a large number of others. We explore the efficient use of the saddlepoint approximation for simulating distributions and provide three examples of the accuracy of these simulations. 相似文献
42.
Due to destructiveness of natural disasters, restriction of disaster scenarios and some human causes, missing data usually occur in disaster decision-making problems. In order to estimate missing values of alternatives, this paper focuses on imputing heterogeneous attribute values of disaster based on an improved K nearest neighbor imputation (KNNI) method. Firstly, some definitions of trapezoidal fuzzy numbers (TFNs) are introduced and three types of attributes (i.e. linguistic term sets, intervals and real numbers) are converted to TFNs. Then the correlated degree model is utilized to extract related attributes to form instances that will be used in K nearest neighbor algorithm, and a novel KNNI method merging with correlated degree model is presented. Finally, an illustrative example is given to verify the proposed method and to demonstrate its feasibility and effectiveness. 相似文献
43.
ABDOLLAH JALILIAN YONGTAO GUAN RASMUS WAAGEPETERSEN 《Scandinavian Journal of Statistics》2013,40(1):119-137
Abstract. Spatial Cox point processes is a natural framework for quantifying the various sources of variation governing the spatial distribution of rain forest trees. We introduce a general criterion for variance decomposition for spatial Cox processes and apply it to specific Cox process models with additive or log linear random intensity functions. We moreover consider a new and flexible class of pair correlation function models given in terms of normal variance mixture covariance functions. The proposed methodology is applied to point pattern data sets of locations of tropical rain forest trees. 相似文献
44.
Consider a random variable S being the sum of a number N of independent and identically distributed random variables Xj (j = 1, 2, ...) where the number N is itself a non-negative integer-valued random variable independent of the Xj An explicit expression of the r-th cumulant of S is given in terms of the cumulants of N and Xj, Asymptotic properties of the distribution of S are also discussed. 相似文献
45.
Christopher S. Withers 《Statistics》2013,47(1):159-166
H. Kres Statistisehe Tafeln zur multlvariaten Analysis. Springer-Verlag, Berlin- Heidel-berg-New York 1975, XVIII, 431 S., 26 Tab., DM 48. D. Rasch: Einführung in die mathematische Statistik - WahrscheinUcllkeitsrechnung und Grundlagen der mathematlsehan Statistlk. VEB Deutscher Verlag delr Wissenschaften, Berlin 1976, 371 S., 37 Abb., 46 'I'ab., 40,– M. D. Rasch: Einführung in die muthematisehe Statlstik - II .Anweuduugen, VEB Deutscher Verlag der Wissenschaften, Berlin 1976. Donald L. Snyder: Random Point Processes. -JohnWiley &; Sons, New York 1975,485 S. 相似文献
46.
ABSTRACTThe recent evolution of asylum and refugee policies in developed countries has been characterised by two apparently contradictory dynamics. Efforts to limit the number of asylum applicants have coincided with the strengthening of rights for asylum seekers and refugees inside existing protection systems. The ‘numbers vs. rights’ model seeks to explain such counter-veiling trends as a trade-off, as the result of attempts to manage costs within given budget constraints. The model suggests that high numbers of migrants will tend to go hand in hand with attempts to restrict their rights, while low numbers will typically be associated with more rights. This paper provides a critical analysis of the model when applied to asylum and refugee policies and examines its explanatory purchase through the analysis of longitudinal data on visa and asylum statistics. We argue that while the model provides an interesting framework through which to analyse executive decisions in this field, it underestimates the opportunities and constraints provided by the institutional context in which policy choices are made. We argue that ‘over-time’ variation in the influence of non-majoritarian institutions (in Europe, increasingly those operating at the EU level) provide a more compelling account of the dynamics of asylum and refugee policies over time than the political economy predictions of a ‘number vs. rights’ trade-off. 相似文献
47.
Ning Zhang 《统计学通讯:理论与方法》2020,49(21):5252-5272
AbstractUnder non‐additive probabilities, cluster points of the empirical average have been proved to quasi-surely fall into the interval constructed by either the lower and upper expectations or the lower and upper Choquet expectations. In this paper, based on the initiated notion of independence, we obtain a different Marcinkiewicz-Zygmund type strong law of large numbers. Then the Kolmogorov type strong law of large numbers can be derived from it directly, stating that the closed interval between the lower and upper expectations is the smallest one that covers cluster points of the empirical average quasi-surely. 相似文献
48.
Tree algorithms are a well-known class of random access algorithms with a provable maximum stable throughput under the infinite population model (as opposed to ALOHA or the binary exponential backoff algorithm). In this article, we propose a tree algorithm for opportunistic spectrum usage in cognitive radio networks. A channel in such a network is shared among so-called primary and secondary users, where the secondary users are allowed to use the channel only if there is no primary user activity. The tree algorithm designed in this article can be used by the secondary users to share the channel capacity left by the primary users.
We analyze the maximum stable throughput and mean packet delay of the secondary users by developing a tree structured Quasi-Birth Death Markov chain under the assumption that the primary user activity can be modeled by means of a finite state Markov chain and that packets lengths follow a discrete phase-type distribution.
Numerical experiments provide insight on the effect of various system parameters and indicate that the proposed algorithm is able to make good use of the bandwidth left by the primary users. 相似文献
49.
Wolfgang Panny 《随机性模型》2016,32(1):160-178
Two-periodic random walks have up-steps and down-steps of one unit as usual, but the probability of an up-step is α after an even number of steps and β = 1 ? α after an odd number of steps, and reversed for down-steps. This concept was studied by Böhm and Hornik[2]. We complement this analysis by using methods from (analytic) combinatorics. By using two steps at once, we can reduce the analysis to the study of Motzkin paths, with up-steps, down-steps, and level-steps. Using a proper substitution, we get the generating functions of interest in an explicit and neat form. The parameters that are discussed here are the (one-sided) maximum (already studied by Böhm and Hornik[2]) and the two-sided maximum. For the asymptotic evaluation of the average value of the two-sided maximum after n random steps, more sophisticated methods from complex analysis (Mellin transform, singularity analysis) are required. The approach to transfer the analysis to Motzkin paths is, of course, not restricted to the two parameters under consideration. 相似文献
50.
文章选取随机变量为系统的随机变量研究含有随机参数混沌系统的Hopf分岔,利用Chebyshev正交多项式逼近理论将含有随机变量的系统转化为等价的确定性系统,通过Hopf分岔定理和Lyapunov系数讨论了随机参数系统的Hopf分岔及稳定性,发现随机系统的渐进稳定性参数区间大小不仅和确定性参数有关,还与随机参数有非常密切的关系. 相似文献