全文获取类型
收费全文 | 1212篇 |
免费 | 23篇 |
国内免费 | 25篇 |
专业分类
管理学 | 225篇 |
民族学 | 3篇 |
人口学 | 3篇 |
丛书文集 | 69篇 |
理论方法论 | 10篇 |
综合类 | 882篇 |
社会学 | 8篇 |
统计学 | 60篇 |
出版年
2024年 | 2篇 |
2023年 | 5篇 |
2022年 | 6篇 |
2021年 | 15篇 |
2020年 | 20篇 |
2019年 | 15篇 |
2018年 | 16篇 |
2017年 | 28篇 |
2016年 | 33篇 |
2015年 | 48篇 |
2014年 | 69篇 |
2013年 | 61篇 |
2012年 | 63篇 |
2011年 | 87篇 |
2010年 | 85篇 |
2009年 | 79篇 |
2008年 | 84篇 |
2007年 | 74篇 |
2006年 | 85篇 |
2005年 | 67篇 |
2004年 | 56篇 |
2003年 | 49篇 |
2002年 | 37篇 |
2001年 | 40篇 |
2000年 | 39篇 |
1999年 | 22篇 |
1998年 | 14篇 |
1997年 | 16篇 |
1996年 | 8篇 |
1995年 | 12篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1983年 | 1篇 |
排序方式: 共有1260条查询结果,搜索用时 15 毫秒
1.
2.
Box–Cox together with our newly proposed transformation were implemented in three different real world empirical problems to alleviate noisy and the volatility effect of them. Consequently, a new domain was constructed. Subsequently, universe of discourse for transformed data was established and an approach for calculating effective length of the intervals was then proposed. Considering the steps above, the initial forecasts were performed using frequently used fuzzy time series (FTS) methods on transformed data. Final forecasts were retrieved from initial forecasted values by proper inverse operation. Comparisons of the results demonstrate that the proposed method produced more accurate forecasts compared with existing FTS on original data. 相似文献
3.
4.
The present article intends to develop some imputation methods to reduce the impact of non response at both the occasions in two-occasion successive (rotation) sampling. Utilizing the auxiliary information, which is only available at the current occasion, estimators have been proposed for estimating the population mean at the current occasion. Estimators for the current occasion are also derived as a particular case when there is non response either on the first occasion or second occasion. Behaviors of the proposed estimators are studied and their respective optimum replacement policies are also discussed. To study the effectiveness of the suggested imputation methods, performances of the proposed estimators are compared in two different situations, with and without non response. The results obtained are demonstrated with the help of empirical studies. 相似文献
5.
Bo-Yan Jou 《统计学通讯:理论与方法》2013,42(10):1730-1740
For a drifted multiple-input and multiple-output (MIMO) system, the double multivariate exponentially weighted moving average (dMEWMA) controller is a popular run-to-run (RTR) controller for adjusting the process mean to a desired target. The stability and performance of dMEWMA controller had been widely studied in literature. Although the dMEWMA controller (with suitable discount matrices) can guarantee long-term stability, it usually requires a moderately large number of runs to bring the process output to approach its desired target if the initial recipe is not chosen appropriately. Due to the initial recipe possibly having an infinite number of feasible solutions for MIMO systems, “how to determine an optimal setting for the initial recipe” turns out to be an interesting research topic. In this article, by solving a constrained optimization problem, we first obtain an optimal initial setting for the input recipe. Then, motivated by this setting, we propose an enhanced dMEWMA controller. The long-term stability conditions and short-term performance of the proposed controller are also addressed. Given a fixed and finite production run, it reveals that the proposed controller has the ability of reducing total mean squared error (TMSE) better than the conventional dMEWMA controller. 相似文献
6.
研究模糊语义必须以查德的“模糊集”理论作指导.运用现代语言学和现代语义学以及相关学科的研究成果来进行研究。这样也就使得研究方法具有多角度、多层次的特点,从而形成一个方法论系统:从整体方法上看,可实行宏观研究与微观分析相结合、定性研究与定量描述相结合、一般规律研究与特殊规律研究相结合的方法;从具体方法上看,应该注重模糊语义学的“综合性的边缘学科”属性,强调不同学科之间的渗透,融合各相关学科的理论和知识,来对模糊语义展开全面而深入的研究。 相似文献
7.
现代的膜式水冷壁制造工艺要求多达20台焊接电源同时工作,当外网原因使车间供电电压波动的时候,焊接电源群同时进行调整。群焊接电源的冲击性载荷对电网进行反激,导致电网的更大波动。文章引入优先级的概念,将自适应神经模糊推理系统(ANFIS)应用到焊接电源群的优先级控制上,设计了自适应神经模糊推理网络,并利用MATLAB平台进行整个焊接系统的建模和仿真。结果表明应用该优先级群控策略,各焊机调整能力加强,调整时间缩短,动态性能得到改善。 相似文献
8.
采用单片机实现了焊管机生产线钢管自动定长切割的控制,并使其具有结构小、功能强控制精度高等优点;介绍了控制器的软硬件设计思想和设计方法. 相似文献
9.
基于Simulink的模糊PID参数自整定控制器的设计与仿真 总被引:1,自引:0,他引:1
针对PID控制器参数整定问题,介绍了一种运用模糊推理实现对PID参数自整定的控制方法,并运用S imu link进行仿真分析,仿真结果表明:模糊PID参数自整定控制较常规PID控制具有较小的超调量和较短的调节时间,以及较好的动态响应特性和稳态特性。 相似文献
10.
针对Ziegler-Nichols算法设计的PID控制器阶跃响应不理想,不具有灵活性等缺点,提出基于粒子群算法与改进
Ziegler-Nichols算法的PID整定方法。采用粒子群算法优化了Ziegler-Nichols算法中的幅值和相角,设计了具有更好性能
指标的PID控制器。实验结果表明采用该方法进行参数整定后的PID控制器响应速度较快,降低了系统的超调量。 相似文献