全文获取类型
收费全文 | 4310篇 |
免费 | 507篇 |
国内免费 | 314篇 |
专业分类
电工技术 | 519篇 |
综合类 | 756篇 |
化学工业 | 535篇 |
金属工艺 | 174篇 |
机械仪表 | 241篇 |
建筑科学 | 351篇 |
矿业工程 | 78篇 |
能源动力 | 247篇 |
轻工业 | 290篇 |
水利工程 | 53篇 |
石油天然气 | 22篇 |
武器工业 | 11篇 |
无线电 | 336篇 |
一般工业技术 | 499篇 |
冶金工业 | 43篇 |
原子能技术 | 5篇 |
自动化技术 | 971篇 |
出版年
2024年 | 44篇 |
2023年 | 215篇 |
2022年 | 221篇 |
2021年 | 267篇 |
2020年 | 226篇 |
2019年 | 147篇 |
2018年 | 84篇 |
2017年 | 165篇 |
2016年 | 172篇 |
2015年 | 173篇 |
2014年 | 396篇 |
2013年 | 474篇 |
2012年 | 625篇 |
2011年 | 654篇 |
2010年 | 467篇 |
2009年 | 384篇 |
2008年 | 153篇 |
2007年 | 40篇 |
2006年 | 34篇 |
2005年 | 22篇 |
2004年 | 10篇 |
2003年 | 6篇 |
2002年 | 18篇 |
2001年 | 11篇 |
2000年 | 12篇 |
1999年 | 11篇 |
1998年 | 7篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 21篇 |
1986年 | 15篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1976年 | 1篇 |
排序方式: 共有5131条查询结果,搜索用时 11 毫秒
81.
基于交往理念的儿童家具设计研究 总被引:1,自引:0,他引:1
目的研究促进儿童交往的家具设计,以培养儿童的交往能力为目的,满足他们的情感需要。方法引入交互设计的研究方法,以行为为对象,通过分析儿童不同时期的交往行为特征,总结归纳儿童交往的行为模式,研究儿童、家具、同伴之间的互动,探索儿童交往行为模式下的儿童家具设计的新思路。结论研究儿童交往行为模式下的家具设计更具有适用性,能促进儿童间的交往,为儿童家具设计的发展提供新的借鉴。 相似文献
82.
83.
84.
人工智能课程设计问题的探讨 总被引:1,自引:0,他引:1
人工智能课程设计是人工智能课程中重要的综合性实践环节,对提高学生理解和掌握人工智能基本概念和算法的能力、对培养学生从智能设计的角度考虑和解决问题的素养都具有重要的作用。结合多年教学实践,从课程设计的重要性、设计的选题、指导方式以及设计报告撰写等方面进行探讨和总结。 相似文献
85.
With consideration that the controller parameters may vary from the designed value when the controller is realized, based on Lyapunov stability theory, a design method of nonfragile guaranteed cost control for a class of Delta operator-formulated uncertain time-delay systems is studied. A sufficient condition for the existence of the nonfragile guaranteed cost controller is given. A numeric example is then given to illustrate the effectiveness and the feasibility of the designed method. The results show that even if the parameters of the designed controller are of variations, the closed-loop system is still asymptotically stable and the super value of the cost function can also be obtained, while the closed-loop system will be unstable if the variations of the controller parameters are not considered when the controller is designed. The nonfragile guaranteed cost controller derived from the traditional shift operator method may cause the closed-loop system to be unstable, while the nonfragile guaranteed cost controller based on Delta operator method can avoid the unstable problem of the closed-loop system. 相似文献
86.
Partner selection is a major issue in the formation of a virtual enterprise. In practice, in the partner selection process, the information about the candidates and their performances are incomplete and uncertain. Vague sets theory is one of the methods used to deal with uncertain information. In this paper, a new method based on vague sets is proposed to deal with the partner selection problem in the formation of a virtual enterprise while the factors of satisfaction degree, due date, cost and the precedence of tasks are taken into account. On the basis of the agreement index of satisfaction degree, the formulated partner selection problems are interpreted so as to maximize the minimum agreement index. To solve the problem, an improved particle swarm optimization (PSO) algorithm is proposed. Finally, the simulation of a numerical example demonstrates that the method is effective. 相似文献
87.
A hybrid data-fusion system using modal data and probabilistic neural network for damage detection 总被引:1,自引:0,他引:1
This paper addresses a novel hybrid data-fusion system for damage detection by integrating the data fusion technique, probabilistic neural network (PNN) models and measured modal data. The hybrid system proposed consists of three models, i.e. a feature-level fusion model, a decision-level fusion model and a single PNN classifier model without data fusion. Underlying this system is the idea that we can choose any of these models for damage detection under different circumstances, i.e. the feature-level model is preferable to other models when enormous data are made available through multi-sensors, whereas the confidence level for each of multi-sensors must be determined (as a prerequisite) before the adoption of the decision-level model, and lastly, the single model is applicable only when data collected is somehow limited as in the cases when few sensors have been installed or are known to be functioning properly. The hybrid system is suitable for damage detection and identification of a complex structure, especially when a huge volume of measured data, often with uncertainties, are involved, such as the data available from a large-scale structural health monitoring system. The numerical simulations conducted by applying the proposed system to detect both single- and multi-damage patterns of a 7-storey steel frame show that the hybrid data-fusion system cannot only reliably identify damage with different noise levels, but also have excellent anti-noise capability and robustness. 相似文献
88.
数据中心内的文件服务存在未授权访问等安全威胁。针对该问题,提出一种基于会话的安全Web文件服务模型,通过分离文件资源数据及其原数据,实现计算资源与存储资源的独立计算,并建立相应的安全模型和安全协议。利用BAN逻辑对协议进行安全性分析,结果证明其可以抵御多种常见攻击。基于Apache的性能测试结果表明,该模型具有较高的安全性及实用性。 相似文献
89.
A neutral data envelopment analysis (DEA) model for cross-efficiency evaluation was recently proposed by Wang and Chin [Wang and Chin (2010b). A neutral DEA model for cross-efficiency evaluation and its extension. Expert Systems with Applications, 37(5), 3666–3675], which maximinimizes the relative efficiency of each output and effectively reduces the number of zero weights of outputs. Since a large number of zero weights may still exist among inputs, this paper proposes a simultaneously input- and output-oriented weight determination DEA model for the cross-efficiency evaluation. The new DEA model proves to reduce the number of zero weights for both inputs and outputs very significantly, as illustrated by numerical examples. The weights determined by the new DEA model are neutral, neither aggressive nor benevolent. 相似文献
90.
Fuzzy quality function deployment (QFD) has been extensively used for translating customer requirements (CRs) into product design requirements (DRs) in fuzzy environments. Existing approaches, however, for rating technical importance of DRs in fuzzy environments are found problematic, either incorrect or inappropriate. This paper investigates how the technical importance of DRs can be correctly rated in fuzzy environments. A pair of nonlinear programming models and two equivalent pairs of linear programming models are developed, respectively, to rate the technical importance of DRs. The developed models are examined and illustrated with two numerical examples. 相似文献