全文获取类型
收费全文 | 9879篇 |
免费 | 1215篇 |
国内免费 | 997篇 |
专业分类
电工技术 | 463篇 |
技术理论 | 2篇 |
综合类 | 1054篇 |
化学工业 | 587篇 |
金属工艺 | 225篇 |
机械仪表 | 465篇 |
建筑科学 | 1068篇 |
矿业工程 | 185篇 |
能源动力 | 97篇 |
轻工业 | 489篇 |
水利工程 | 189篇 |
石油天然气 | 196篇 |
武器工业 | 69篇 |
无线电 | 899篇 |
一般工业技术 | 609篇 |
冶金工业 | 682篇 |
原子能技术 | 43篇 |
自动化技术 | 4769篇 |
出版年
2024年 | 68篇 |
2023年 | 227篇 |
2022年 | 353篇 |
2021年 | 472篇 |
2020年 | 404篇 |
2019年 | 346篇 |
2018年 | 321篇 |
2017年 | 366篇 |
2016年 | 455篇 |
2015年 | 441篇 |
2014年 | 603篇 |
2013年 | 530篇 |
2012年 | 540篇 |
2011年 | 581篇 |
2010年 | 455篇 |
2009年 | 497篇 |
2008年 | 580篇 |
2007年 | 536篇 |
2006年 | 542篇 |
2005年 | 542篇 |
2004年 | 444篇 |
2003年 | 362篇 |
2002年 | 360篇 |
2001年 | 286篇 |
2000年 | 269篇 |
1999年 | 208篇 |
1998年 | 164篇 |
1997年 | 168篇 |
1996年 | 134篇 |
1995年 | 123篇 |
1994年 | 129篇 |
1993年 | 99篇 |
1992年 | 97篇 |
1991年 | 81篇 |
1990年 | 57篇 |
1989年 | 55篇 |
1988年 | 33篇 |
1987年 | 15篇 |
1986年 | 27篇 |
1985年 | 23篇 |
1984年 | 19篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 4篇 |
1980年 | 11篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1964年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 10 毫秒
41.
Knowledge-based computing, in general, suffers from an inherent open-endedness that precludes its application in time-bounded domains where an answer must be computed within a stipulated time limit. We examine a two-way improvement of the shortcomings: a knowledge representation scheme that provides easy access to relevant knowledge and thereby reduces search time, and a reasoning scheme that is algorithmic in nature and thus makes computational requirements meaningfully estimable.In this work, we offer a cache-based architecture that is capable of both storing knowledge in different formats (e.g. rules, cases), and invoking an appropriate reasoning scheme to fit the available computing time. The cache helps in retrieving the most relevant pieces of knowledge (not only exact matches) required for solving a given problem. This cache relies on a reasoning tactic, knowledge interpolation, that can generate a solution from two near-matches in an algorithmic way, to generate time-bounded solutions. We illustrate the design of such a cache for solving resource allocation problems in the domain of shortwave radio transmission and evaluate its performance in observing imposed temporal bounds. 相似文献
42.
文章分析了二次绕组带有抽头的套管电流互感器(CT),其二次端子接线错误对CT变比的影响。指出在实际工作当中应当正确理解“CT二次线圈严禁开路”所指含义,灵活应用,以保证保护装置可靠动作。 相似文献
43.
曹文华 《河北工程技术高等专科学校学报》2004,(1):29-31
分析介绍了消防水泵、电动防火卷帘、防烟排烟设施、非消防电源断电、电梯等设施的联动控制系统的设计方法,并提出了设计中应注意的问题和合理化建议。 相似文献
44.
Horizon control, maintaining the alignment of the shearer’s exploitation gradient with the coal seam gradient, is a key technique in longwall mining automation. To identify the coal seam gradient, a geological model of the coal seam was constructed using in-seam seismic surveying technology. By synthesizing the control resolution of the range arm and the geometric characteristics of the coal seam, a gradient identification method based on piecewise linear representation(PLR) is proposed. To achi... 相似文献
45.
李永国 《宁波工程学院学报》1996,(1)
通过控制产生框架最大剪力楼层的层间弹性位移与居高之比来确定地震作用下框架──剪力培结构中剪力墙的数量,并使得其更为经济。 相似文献
46.
本文通过对鞍山市中年人消费观念的调查,运用SPSS因子分析方法,总结了他们的消费类型,时商家、企业以及销售商具有参考价值。 相似文献
47.
Paul G. Skokowski 《Minds and Machines》1994,4(3):333-344
I examine whether it is possible for content relevant to a computer's behavior to be carried without an explicit internal representation. I consider three approaches. First, an example of a chess playing computer carrying emergent content is offered from Dennett. Next I examine Cummins response to this example. Cummins says Dennett's computer executes a rule which is inexplicitly represented. Cummins describes a process wherein a computer interprets explicit rules in its program, implements them to form a chess-playing device, then this device executes the rules in a way that exhibits them inexplicitly. Though this approach is intriguing, I argue that the chess-playing device cannot exist as imagined. The processes of interpretation and implementation produce explicit representations of the content claimed to be inexplicit. Finally, the Chinese Room argument is examined and shown not to save the notion of inexplicit information. This means the strategy of attributing inexplicit content to a computer which is executing a rule, fails.I wish to thank Fred Dretske, JOhn Perry, and an anonymous reviewer for helpful comments and suggestions. Earlier versions of this paper were read at the American Philosophical Association Pacific Division Meeting in San Francisco in March, 1993, and at the 7th International Conference on Computing and Philosophy in Orlando in August, 1992. 相似文献
48.
钢材酸洗时添加缓蚀剂是一种有效、经济的防腐蚀方法,研究缓蚀剂对其作用机理,发展和完善缓蚀剂理论,已成为研究热点.通过失重试验、动电位极化曲线、交流阻抗谱测试及扫描电镜(SEM)方法研究了新型三氮唑化合物1-(4-氟基苯)-3-[4-(1,2,4-三氮唑-1-甲氧基)-苯]-丙烯缓蚀剂(FTPP)在0.5mol/,L H2SO4溶液中对Q235钢的缓蚀作用.结果表明:FTPP对Q235钢的缓蚀效果与自身浓度有关,在0.5mol/L H2SO4中当其达到10-3 mol/,L时,缓蚀率高达92.8%,能同时抑制腐蚀的阴、阳极反应过程,它是一种混合型缓蚀剂;Q235钢的阻抗值随FTPP浓度增加而增大,FTPP在钢表面的吸附符合Langmuir等温式. 相似文献
49.
Abstract: As an improvement of the intensity correlation used widely in conventional electronic speckle photography, we propose a new technique for displacement measurement based on correlating Stokes-like parameters derivatives for transformed speckle patterns. The method is based on a Riesz transform of the intensity speckle pattern, which converts the original real-valued signal into a complex signal. In closest analogy to the polarisation of a vector wave, the Stokes-like vector constructed from the spatial derivative of the generated complex signal has been applied for correlation. Experimental results are presented that demonstrate the validity and advantage of the proposed pseudo-Stokes vector correlation technique over conventional intensity correlation technique. 相似文献
50.
纯气动步进控制回路的设计及应用 总被引:1,自引:1,他引:0
研究了Festo公司一种新型气动步进控制模块的结构、工作原理,结合实例介绍了使用这种气动步进控制模块来设计步进控制回路的方法。 相似文献