全文获取类型
收费全文 | 341741篇 |
免费 | 24717篇 |
国内免费 | 16128篇 |
专业分类
电工技术 | 40579篇 |
技术理论 | 28篇 |
综合类 | 35602篇 |
化学工业 | 19584篇 |
金属工艺 | 12585篇 |
机械仪表 | 31441篇 |
建筑科学 | 46831篇 |
矿业工程 | 12712篇 |
能源动力 | 11135篇 |
轻工业 | 9775篇 |
水利工程 | 10452篇 |
石油天然气 | 10613篇 |
武器工业 | 5118篇 |
无线电 | 29116篇 |
一般工业技术 | 24393篇 |
冶金工业 | 9815篇 |
原子能技术 | 2924篇 |
自动化技术 | 69883篇 |
出版年
2024年 | 1183篇 |
2023年 | 3182篇 |
2022年 | 5930篇 |
2021年 | 7458篇 |
2020年 | 8180篇 |
2019年 | 6094篇 |
2018年 | 5716篇 |
2017年 | 7823篇 |
2016年 | 9140篇 |
2015年 | 10496篇 |
2014年 | 22489篇 |
2013年 | 18513篇 |
2012年 | 24782篇 |
2011年 | 26499篇 |
2010年 | 20925篇 |
2009年 | 21298篇 |
2008年 | 20711篇 |
2007年 | 25920篇 |
2006年 | 22719篇 |
2005年 | 20275篇 |
2004年 | 16475篇 |
2003年 | 15096篇 |
2002年 | 11626篇 |
2001年 | 9770篇 |
2000年 | 8051篇 |
1999年 | 6440篇 |
1998年 | 4942篇 |
1997年 | 4099篇 |
1996年 | 3557篇 |
1995年 | 2942篇 |
1994年 | 2435篇 |
1993年 | 1656篇 |
1992年 | 1373篇 |
1991年 | 1030篇 |
1990年 | 780篇 |
1989年 | 687篇 |
1988年 | 501篇 |
1987年 | 312篇 |
1986年 | 192篇 |
1985年 | 212篇 |
1984年 | 218篇 |
1983年 | 165篇 |
1982年 | 159篇 |
1981年 | 96篇 |
1980年 | 86篇 |
1979年 | 66篇 |
1978年 | 48篇 |
1977年 | 37篇 |
1976年 | 26篇 |
1959年 | 30篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
41.
Joshua Vaughan Joel Fortgang William Singhose Jeffrey Donnell Thomas Kurfess 《Mechatronics》2008,18(4):179-186
It is commonly accepted that hands-on experiences increase both learning and enjoyment during coursework. Mechatronics projects provide both interesting and relevant hands-on experiences for a wide range of topics including design processes, basic mechatronics concepts, technical communication, and working in a group environment. ME2110: Creative Decisions and Design at Georgia Tech integrates mechatronics and technical communication into a sophomore level mechanical design class. This paper describes the course in detail, highlighting the course goals and layout, tools provided to the students, industry involvement, and the main challenges of administering such a course. 相似文献
42.
Optimal synthesis of tunable elastic wave-guides 总被引:1,自引:0,他引:1
Anton Evgrafov Cory J. Rupp 《Computer Methods in Applied Mechanics and Engineering》2008,198(2):292-301
Topology optimization, or control in the coefficients of partial differential equations, has been successfully utilized for designing wave-guides with precisely tailored functionalities. For many applications it would be desirable to have the possibility of drastically altering the wave-guiding properties of a device “on the fly,” in a controllable manner as an influence of some external input. This would enable wave-guides with highly non-linear input-output mappings, such as for example controllable wave switches.In this paper, we propose using finite elastic pre-straining for the purpose of tuning a wave-guide. In order to systematically formulate and solve the wave-guide synthesis problems we utilize mathematical programming methods in conjunction with topology optimization for parametrizing the design space. The resulting extremal problem is, from a practical point, equivalent to finding an optimal subdivision of a given control volume into two disjoint subsets occupied by two different materials, normally resulting in a highly heterogeneous elastic body with desired wave-guiding functionalities in the original and finitely deformed configurations.The proposed methodology is illustrated with numerical examples. 相似文献
43.
44.
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
45.
The introduction of multiple, independent production lines has helped many firms to increase their production flexibility, provide for redundancy when equipment breaks down, reduce idle time and labor costs, and achieve many other benefits. This paper introduces and formalizes the multiple U-line balancing problem. Optimal solution methodologies are provided for Type I (minimize the number of stations for a given cycle time), Type II (minimize the cycle time for a given number of stations), and cost-minimization line-balancing problems. A branch-and-bound algorithm is also developed for the situation in which equipment requirements are dependent on the line configuration and the task assignment to stations. Computational results indicate that the greatest benefit of exploiting multiple lines occurs for smaller cycle-time problems that require higher output. 相似文献
46.
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
47.
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
48.
室内设计中绿色设计的功效 总被引:1,自引:0,他引:1
绿色设计是一种将功能主义与可持续发展思想相结合的设计。文中就其形成的背景、设计原理及在室内设计领域中的应用进行一些探讨。 相似文献
49.
利用Excel表格进行供暖系统计算 总被引:2,自引:0,他引:2
利用Excel表格进行供暖工程设计计算,可以减少工作量,提高工作效率。介绍了房间热负荷和供暖管道水力计算方法。 相似文献
50.
This paper reports the findings of a detailed study of Web-based systems design (WBSD) practices in Ireland based on data
collected over a 3-year period (2002–2005), the objectives of which were to (1) contribute towards a richer understanding
of the current “real-world” context of WBSD by characterising the profile of a typical project (team size, timeframe, nature
of requirements, etc.) and identifying the key challenges, constraints, and imperatives (i.e. “mediating factors”) faced by
Web-based system designers, and (2) understand how those contextual parameters and mediating factors influence the activity
of WBSD as regards the selection and enactment of whatever design practices are therefore engaged (i.e. the use of methods,
procedures, etc.). Data was gathered through a survey which yielded 165 usable responses, and later through a series of semi-structured
qualitative interviews. Using grounded theory, an explanatory conceptual framework is derived, based on an extension of the
“method-in-action” model, the application of which to WBSD has not been previously investigated in depth. It is proposed that
this framework of WBSD issues is valuable in a number of ways to educators, researchers, practitioners, and method engineers. 相似文献