全文获取类型
收费全文 | 111636篇 |
免费 | 13051篇 |
国内免费 | 7579篇 |
专业分类
电工技术 | 11492篇 |
技术理论 | 4篇 |
综合类 | 11414篇 |
化学工业 | 9903篇 |
金属工艺 | 8748篇 |
机械仪表 | 11731篇 |
建筑科学 | 7443篇 |
矿业工程 | 6709篇 |
能源动力 | 6228篇 |
轻工业 | 1849篇 |
水利工程 | 4178篇 |
石油天然气 | 6068篇 |
武器工业 | 3685篇 |
无线电 | 12671篇 |
一般工业技术 | 10277篇 |
冶金工业 | 3623篇 |
原子能技术 | 1698篇 |
自动化技术 | 14545篇 |
出版年
2024年 | 540篇 |
2023年 | 1570篇 |
2022年 | 3111篇 |
2021年 | 3497篇 |
2020年 | 3821篇 |
2019年 | 2829篇 |
2018年 | 2804篇 |
2017年 | 3783篇 |
2016年 | 4563篇 |
2015年 | 4963篇 |
2014年 | 7701篇 |
2013年 | 7214篇 |
2012年 | 9157篇 |
2011年 | 9717篇 |
2010年 | 7053篇 |
2009年 | 7042篇 |
2008年 | 6465篇 |
2007年 | 8086篇 |
2006年 | 6994篇 |
2005年 | 5815篇 |
2004年 | 4854篇 |
2003年 | 3993篇 |
2002年 | 3170篇 |
2001年 | 2680篇 |
2000年 | 2166篇 |
1999年 | 1749篇 |
1998年 | 1346篇 |
1997年 | 1081篇 |
1996年 | 979篇 |
1995年 | 762篇 |
1994年 | 640篇 |
1993年 | 446篇 |
1992年 | 381篇 |
1991年 | 302篇 |
1990年 | 233篇 |
1989年 | 188篇 |
1988年 | 154篇 |
1987年 | 61篇 |
1986年 | 79篇 |
1985年 | 35篇 |
1984年 | 37篇 |
1983年 | 31篇 |
1982年 | 30篇 |
1981年 | 15篇 |
1980年 | 18篇 |
1979年 | 19篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1959年 | 24篇 |
1951年 | 27篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
Chih-Wea Wang Chi-Feng Wu Jin-Fu Li Cheng-Wen Wu Tony Teng Kevin Chiu Hsiao-Ping Lin 《Journal of Electronic Testing》2002,18(6):637-647
In this paper we propose a novel built-in self-test (BIST) design for embedded SRAM cores. Our contribution includes a compact and efficient BIST circuit with diagnosis support and an automatic diagnostic system. The diagnosis module of our BIST circuit can capture the error syndromes as well as fault locations for the purposes of repair and fault/failure analysis. In addition, our design provides programmability for custom March algorithms with lower hardware cost. The combination of the on-line programming mode and diagnostic system dramatically reduces the effort in design debugging and yield enhancement. We have designed and implemented test chips with our BIST design. Experimental results show that the area overhead of the proposed BIST design is only 2.4% for a 128 KB SRAM, and 0.65% for a 2 MB one. 相似文献
32.
用快切装置替代备自投装置提高厂用电安全可靠性 总被引:3,自引:0,他引:3
指出目前厂用电切换装置存在的不足,分析了快切装置的基本原理以及厂用电事故下的成功快切对电厂安全生产的意义,说明了在厂用电切换中尽快应用快切装置的必要性。 相似文献
33.
Gabriel Wainer 《Software》2002,32(13):1261-1306
The features of a toolkit for modeling and simulation based on the DEVS formalism are presented. The tool is built as a set of independent software pieces running on different platforms. Not only are the main characteristics of the environment presented, a focus on its use is also considered by inclusion of application examples for a variety of problems. Many models can be defined in an automated fashion, simplifying the construction of new models and easing their verification. The use of this formal approach has allowed the development of safe and cost‐effective simulations, significantly reducing development time. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
34.
Alessandro Fantoni Manuela Viera Rodrigo Martins 《Solar Energy Materials & Solar Cells》2002,73(2):148
In this paper a set of one-dimensional simulations of a-Si:H p–i–n junctions under different illumination conditions and with different intrinsic layer are presented. The simulation program ASCA permits the analysis of the internal electrical behaviour of the cell allowing a comparison among the different internal configurations determined by a change in the input set. Results about the internal electric configuration will be presented and discussed outlining their influence on the current tension characteristic curve. Considerations about the drift–diffusion and the generation–recombination balance distributions, outlined by the simulation, can be used to explain the correlation between the basic device output, the i-layer characteristics (thickness and DOS), the incident radiation intensity and photon energy. 相似文献
35.
36.
文章通过分析多相流模拟井的实际工作要求 ,提出了简单实用的流量自动控制模型。应用成型的计算机数据采集和控制模块及稳定可靠的流量控制部件 ,实现了各相流量的自动控制过程。该流量自动控制系统调节精度高、速度快、整体造价低 ,在实际应用中取得了良好的效果。 相似文献
37.
38.
在KZON-50/120空分设备的安装调试和试运行过程中,对其机械和电器部分进行了多处改造,克服了原设计中存在的不足之处。改造后,机械和电器性能更加趋于合理,操作简单,便于维护,降低了制气费用,提高了制气纯度和经济效益,保证了空分设备更加安全可靠运行。 相似文献
39.
In the paper, a model typical for contact situations of automotive brakes is established based on the method of movable cellular automata. The processes taking place at local contacts in an automotive brake system are analysed. Based on microscopic and micro-analytical observations, the following contact situations were simulated: (i) a couple of ferritic steel against pearlitic steel, both covered by an oxide layer mixed with graphite nanoparticles and (ii) the same situation but without oxide layers. The results of calculated mean coefficients of friction of the oxide-on-oxide contact correspond well to expected values for a real braking system, whereas steel-on-steel contact are twice as high. This allows one to make some conclusions; for example, oxide formation will take place more quickly than friction layer elimination, and finally this is responsible for the stabilisation of the coefficient of friction. 相似文献
40.
Toshihiko Hoshide Junpei Fujita 《Journal of Materials Engineering and Performance》2008,17(5):627-632
Strength of ground ceramics may be affected by residual stress as well as surface flaws induced by grinding. Strength prediction
for ground ceramics is convenient for mechanical design of ceramic components. In this article, a numerical procedure based
on fracture mechanics was proposed to estimate strength distribution of ground ceramics by considering grinding-induced residual
stress. Bending strength and residual stress of ground ceramics were measured for three grinding-conditions. By comparison
of simulated results with experimental ones, it was revealed that strength characteristics in experiments were well simulated
by using the proposed procedure. 相似文献