全文获取类型
收费全文 | 251650篇 |
免费 | 20680篇 |
国内免费 | 14876篇 |
专业分类
电工技术 | 37548篇 |
技术理论 | 23篇 |
综合类 | 27968篇 |
化学工业 | 12090篇 |
金属工艺 | 10341篇 |
机械仪表 | 24318篇 |
建筑科学 | 19577篇 |
矿业工程 | 10624篇 |
能源动力 | 8727篇 |
轻工业 | 7420篇 |
水利工程 | 6809篇 |
石油天然气 | 7133篇 |
武器工业 | 4074篇 |
无线电 | 23978篇 |
一般工业技术 | 13540篇 |
冶金工业 | 8244篇 |
原子能技术 | 2367篇 |
自动化技术 | 62425篇 |
出版年
2024年 | 951篇 |
2023年 | 2621篇 |
2022年 | 5089篇 |
2021年 | 6202篇 |
2020年 | 6600篇 |
2019年 | 4817篇 |
2018年 | 4366篇 |
2017年 | 6078篇 |
2016年 | 7172篇 |
2015年 | 8373篇 |
2014年 | 15748篇 |
2013年 | 13257篇 |
2012年 | 18576篇 |
2011年 | 19674篇 |
2010年 | 14829篇 |
2009年 | 14851篇 |
2008年 | 15082篇 |
2007年 | 19333篇 |
2006年 | 17518篇 |
2005年 | 15593篇 |
2004年 | 12703篇 |
2003年 | 11424篇 |
2002年 | 8749篇 |
2001年 | 7394篇 |
2000年 | 6096篇 |
1999年 | 4912篇 |
1998年 | 3670篇 |
1997年 | 2996篇 |
1996年 | 2614篇 |
1995年 | 2248篇 |
1994年 | 1867篇 |
1993年 | 1259篇 |
1992年 | 1049篇 |
1991年 | 760篇 |
1990年 | 630篇 |
1989年 | 532篇 |
1988年 | 389篇 |
1987年 | 207篇 |
1986年 | 139篇 |
1985年 | 132篇 |
1984年 | 108篇 |
1983年 | 104篇 |
1982年 | 82篇 |
1981年 | 69篇 |
1980年 | 56篇 |
1979年 | 52篇 |
1978年 | 38篇 |
1977年 | 30篇 |
1976年 | 24篇 |
1959年 | 24篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
11.
12.
Torsten Bohlin Stefan F. Graebe 《International Journal of Adaptive Control and Signal Processing》1995,9(6):465-490
Grey box identification refers to the practice of identifying dynamical systems in model structures exploiting partial prior information. This contribution reviews a method for stochastic grey box identification and surveys experiences and lessons of applying it to a number of industrial processes. Issues to be addressed include advantages and costs of introducing stochastics into the model, the question of what contribution must be expected from the model designer as opposed to what can be formalized in computer algorithms, and an outlook on future plans to resolve present shortcomings. 相似文献
13.
This paper presents an efficient method which provides the optimal generation mix and the optimal generation construction process. The approximation method in which the dynamic programming technique and gradient method are combined is applied to determine the optimal generation mix with hydropower generation technologies. The successive approximations dynamic programming (SADP) technique, which is very suitable for high-dimensional multistage decision process problems, is used for obtaining the optimal generation construction process. The effectiveness and feasibility of the developed technique are demonstrated on a practical power system model which has five types of generation technologies including a hydropower generation technology. 相似文献
14.
介绍了引黄工程五座泵站的火灾自动报警系统的组成及功能,对泵站的火灾探测系统、报警系统、联动控制系统、灭火系统、控制台等原理进行了详细说明,供同行参考借鉴。 相似文献
15.
Shunsuke Ohashi 《Electrical Engineering in Japan》2005,150(1):71-77
Magnetic bearing using pinning force of a permanent magnet and a high‐temperature superconductor has been developed. Additional permanent magnet is introduced to increase the levitation force of the magnetic bearing. In this hybrid magnetic bearing system, levitation force is mainly given by the repulsive force of the permanent magnets, and stability for the lateral direction is given by pinning force of the superconductor. The experimental device is developed. A ring‐type superconductor and a bulk one are examined. Levitation characteristics of the hybrid magnetic bearing are measured. The bulk superconductor shows better characteristics of both levitation and lateral stability than the ring one. Levitation force of the hybrid system becomes about twice as large as that of the nonhybrid one. Although, the repulsive force of the permanent magnet decreases the lateral stability of the system, its influence becomes small by choosing an adequate position of the permanent magnets and the superconductor. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(1): 71–77, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10350 相似文献
16.
Kotaro Matsuuchi Tadashi Fukami Nobuyuki Naoe Ryoichi Hanaoka Shinzo Takata Toshio Miyamoto 《Electrical Engineering in Japan》2005,150(2):43-49
This paper presents a method of predicting the steady‐state performance of a new hybrid‐excitation synchronous machine (HESM) theoretically. The field pole of this HESM is axially divided into two parts; one is an excitation part and the other a permanent‐magnet (PM) part. A nonlinear equivalent circuit, which can include the saliency of the rotor and the magnetic saturation due to the iron core, is derived. Based on this equivalent circuit, the steady‐state performance of the HESM is calculated, and the results are confirmed through experiments. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 43–49, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20033 相似文献
17.
大型水轮发电机组励磁变压器参数及绝缘方式的选择--由三峡机组励磁系统投运引起的思考 总被引:1,自引:0,他引:1
结合三峡机组励磁系统的调试及投运经验,对大型水电机组静止自励系统选型中存在的一些关键性技术课题进行分析与论证,期望得出的结论有助于在大型水轮发电机组励磁系统参数选择和在提高机组运行安全、可靠性方面提供有益的借鉴。文中提出的励磁系统设计新理念仅代表个人的观点。 相似文献
18.
对中、美两国高校高水平运动队管理体制的探讨 总被引:15,自引:0,他引:15
彭中东 《武汉工业学院学报》2003,22(2):125-128
通过调查和查阅了大量的资料,对中、美两国的高校高水平运动队的管理体制进行了比较,旨在通过学习和借鉴将我国高校的高水平运动队管理体制不断的完善,提供一定的参考。 相似文献
19.
John Tsinias 《Systems & Control Letters》1991,17(1)
In this paper we generalize the Vidyasagar's well known theorem on the local stabilizability problem of nonlinear systems using state detection [11]. Our purpose is to prove that if a system is weakly detectable and stabilizable by means of a continuous state feedback u = γ(x), for which no differentiability assumption is imposed, then the system is also stabilized by the law u = γ(z), where z is the output of a weak detector for the state x. The result above is applicable to several cases not covered by other works. 相似文献
20.
Udayan Nandkeolyar David P. Christy 《International Journal of Flexible Manufacturing Systems》1992,4(3-4):267-292
Evaluating the design of flexible manufacturing systems is complex. Developing a measure of performance useful for evaluating alternate designs continues to be interesting. Here, total productivity of the system is proposed as an appropriate measure. Specification of parameters based upon strategic considerations for this measure are discussed. Finally, the usefulness of the measure is demonstrated through an example. 相似文献