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71.
There is a natural order to most events in life: Everything from learning to read to DNA sequences in molecular biology follows some predetermined, structured methodology that has been refined to yield improved results. Likewise, it would seem that firms could benefit by adopting and implementing technologies in some logical way so as to increase their overall performance. In this study of 555 hospitals, we investigate the order in which medical technologies are transformed into information technologies through a process of converting them from stand‐alone technologies to interoperable, integrated information systems and whether certain configurations of sequences of integration yield additional value. We find that sequence does matter and that hospitals that integrated foundational technologies first—which in this case are known to be more complex—tend to perform better. Theoretical and practical implications of this finding and others are discussed.  相似文献   
72.
In this work we present a flexible class of linear models to treat observations made in discrete time and continuous space, where the regression coefficients vary smoothly in time and space. This kind of model is particularly appealing in situations where the effect of one or more explanatory processes on the response present substantial heterogeneity in both dimensions. We describe how to perform inference for this class of models and also how to perform forecasting in time and interpolation in space, using simulation techniques. The performance of the algorithm to estimate the parameters of the model and to perform prediction in time is investigated with simulated data sets. The proposed methodology is used to model pollution levels in the Northeast of the United States.  相似文献   
73.
Any continuous bivariate distribution can be expressed in terms of its margins and a unique copula. In the case of extreme‐value distributions, the copula is characterized by a dependence function while each margin depends on three parameters. The authors propose a Bayesian approach for the simultaneous estimation of the dependence function and the parameters defining the margins. They describe a nonparametric model for the dependence function and a reversible jump Markov chain Monte Carlo algorithm for the computation of the Bayesian estimator. They show through simulations that their estimator has a smaller mean integrated squared error than classical nonparametric estimators, especially in small samples. They illustrate their approach on a hydrological data set.  相似文献   
74.
本文研究了带有不连续项的 Volterra积分方程的最小和最大解 ,并证明了参考文献 [1]中的主要结果的条件可被较弱条件代替  相似文献   
75.
利用最小化代价函数的方法推导了一种谱分析的多窗口。性能分析的结果表明,此方法与离散长球序列多窗口谱分析方法具有相当的估计偏差与方差性能。与离散长球序列多窗口相比,此方法得到的多窗口具有直观的解析表达式而无须求解矩阵的特征分解问题,因而具有较小的计算量。通过对离散白噪声与AR过程进行的多窗口谱分析对比实验,验证了此方法的有效性和正确性。  相似文献   
76.
This paper presents a limited assessment of the conservatism of the Accident Sequence Evaluation Program (ASEP) human reliability analysis (HRA) procedure described in NUREG/CR-4772. The data for this study are derived from simulator examination reports from the NRC requalification examination cycle for nuclear power plant operators. The ASEP procedure was used to estimate human error probability (HEP) values for critical tasks, and the HEP results were compared with the failure rates observed in the examinations. The ASEP procedure was applied by PNNL operator license examiners who supplemented the limited information in the examination reports with expert judgment based upon their extensive simulator examination experience. Comparison of the average of the ASEP HEP values with the fraction of the population actually failed and demonstrated that the ASEP HEP values are larger (conservative) by a statistically significant average factor of two. Partitioning of tasks into subgroups based on the ASEP HEP values and comparison of the subgroup average ASEP HEP values with observed subgroup failure rates showed little or no conservatism for small ASEP HEP values, but considerable conservatism for larger ASEP HEP values.  相似文献   
77.
In this paper, we introduce two new modified scrambled Faure sequences based on linear digit scrambling method with good two-dimensional projections in consecutive dimensions using two new linear digit scrambling matrices for linear and nonlinear scrambled Faure sequences. Also, we present performance of our two new scrambling methods by two-dimensional projections and test-integrals.  相似文献   
78.
In this paper, the author examines the different uses and meanings of the usual expression “post-apartheid.” It has been used extensively in the social sciences, political discourse and the media since the mid-1980s. But what does it refer to, and has it always meant the same thing over the last 20 years? To answer that question, the author reviews the different ways she has used the notion in her research into workers’ forms of thinking and political subjectivities in South Africa since 1996. She distinguishes between its use as a chronological marker, an academic concept open to various problematics and epistemological decisions and a notion used by interviewees under various acceptations. She concentrates more specifically on the sequential implications of the adverb “post” in her work and argues that there have been political sequences in what she (with others) has named “post-apartheid.” She concludes that she intends to stop using this term in order to concentrate on identifying the current political sequence in South Africa.  相似文献   
79.
未来的移动通信系统要求提供的数据传输速率将高达100Mb/s以上,支持的业务也将从语音业务扩展到多媒体业务(包括实时的流媒体业务)。该文提出采用m序列的不同循环移位来构建CCSK序列,并在前导CAZAC序列上叠加CCSK序列,以用于隐含承载接入信息。为了减少两个序列之间的相互影响,调整两种序列之间的能量比例以及采用干扰消除,将显著提高两种序列的检测性能。  相似文献   
80.
直接序列扩频信号PN序列盲估计方法   总被引:3,自引:0,他引:3  
在非协作信息侦测情况下,提出了一种实用的直接序列扩频(DS-SS)通信信号PN码序列的快速盲估计方法。该方法根据DS-SS基带信号的特点,首先采用二阶循环统计量估计PN码周期,然后利用分段互相关平均估计PN码同步始点;并在准确预估计这2个参数的基础上,将接收信号以PN码周期分成多个时段,利用多重互相关方法估计PN码序列。理论分析与仿真表明,该方法在截获信号信噪比很低的情况下有很好的估计性能,且无需任何先验知识,对PN码码型也没有任何限制,是一种有效的快速盲估计方法。  相似文献   
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