全文获取类型
收费全文 | 7892篇 |
免费 | 1024篇 |
国内免费 | 693篇 |
专业分类
电工技术 | 601篇 |
技术理论 | 3篇 |
综合类 | 1146篇 |
化学工业 | 584篇 |
金属工艺 | 190篇 |
机械仪表 | 324篇 |
建筑科学 | 1064篇 |
矿业工程 | 185篇 |
能源动力 | 86篇 |
轻工业 | 471篇 |
水利工程 | 202篇 |
石油天然气 | 182篇 |
武器工业 | 138篇 |
无线电 | 1136篇 |
一般工业技术 | 413篇 |
冶金工业 | 532篇 |
原子能技术 | 36篇 |
自动化技术 | 2316篇 |
出版年
2024年 | 58篇 |
2023年 | 178篇 |
2022年 | 268篇 |
2021年 | 341篇 |
2020年 | 288篇 |
2019年 | 281篇 |
2018年 | 216篇 |
2017年 | 277篇 |
2016年 | 296篇 |
2015年 | 328篇 |
2014年 | 545篇 |
2013年 | 484篇 |
2012年 | 558篇 |
2011年 | 639篇 |
2010年 | 504篇 |
2009年 | 488篇 |
2008年 | 473篇 |
2007年 | 487篇 |
2006年 | 441篇 |
2005年 | 456篇 |
2004年 | 335篇 |
2003年 | 284篇 |
2002年 | 271篇 |
2001年 | 209篇 |
2000年 | 168篇 |
1999年 | 153篇 |
1998年 | 97篇 |
1997年 | 85篇 |
1996年 | 77篇 |
1995年 | 39篇 |
1994年 | 61篇 |
1993年 | 48篇 |
1992年 | 35篇 |
1991年 | 24篇 |
1990年 | 22篇 |
1989年 | 25篇 |
1988年 | 10篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 6篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1980年 | 4篇 |
1979年 | 5篇 |
1962年 | 2篇 |
1961年 | 3篇 |
1960年 | 2篇 |
1959年 | 2篇 |
1955年 | 2篇 |
排序方式: 共有9609条查询结果,搜索用时 597 毫秒
31.
32.
一种适合协同工作系统的安全认证方案 总被引:2,自引:0,他引:2
针对网络化协同工作系统的安全认证需求,综合应用Kerberos协议、X.509证书和口令认证技术,借鉴PKI的思想,设计了一种适合网络化协同工作系统的灵活而易于扩展的安全认证方案。这个方案能够保证证书的安全分发,满足网络化协同工作系统对分散、动态的用户安全身份认证的要求。 相似文献
33.
A survey of CSCW systems 总被引:4,自引:0,他引:4
Tom Rodden 《Interacting with computers》1991,3(3):319-353
Over the last decade, computer supported cooperative work (CSCW) has emerged as an identifiable research area that focuses on the role of the computer in group work. CSCW is a generic term which combines the understanding of the nature of group working with the enabling technologies of computer networking, systems support and applications. The paper examines the classes of system which have emerged to support cooperative working. A framework for characterising and describing CSCW systems is presented and four major classes of cooperative system identified. Each of these classes of cooperative system are examined highlighting their general characteristics and applicability to CSCW. 相似文献
34.
35.
The aim of this study was to bring to the surface the strategic use of imitative processes in the context of a 2-route model: (a) direct imitation, used in reproducing new, meaningless actions, and (b) imitation based on stored semantic knowledge of familiar meaningful actions. Three experiments were carried out with healthy participants who reproduced meaningful and meaningless actions within an established time limit. The study investigated 3 factors that could potentially affect the selection of processes used for imitation: (a) the composition of the experimental list (blocked or mixed presentation), (b) the presence-absence of instructions (Experiments 1 and 2), and (c) the relative proportions of the stimuli (Experiment 3). Overall, the results suggest that each of these factors influences the selection of imitative strategies in healthy individuals with temporarily reduced capacities, as happens in the case of brain-damaged patients. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
36.
Previous research yielded inconsistent results regarding the memory organization of self-performed actions. The authors propose that task performance changes the very basis of memory organization. Enactment during study and test (Experiment 1) yielded stronger enactive clustering (based on motor-movement similarities), whereas verbal encoding yielded stronger conceptual clustering (based on semantic-episodic similarities). Enactment enhanced memory quantity and memory accuracy. Both measures increased with enactive clustering under self-performance instructions but with conceptual clustering under verbal instructions. Enactment only during study (Experiment 2) or only during testing (Experiment 3) also enhanced enactive clustering. It is proposed that different conditions affect the relative salience of different types of memory organization and their relative contribution to recall. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
37.
Visually perceiving an action may activate corresponding motor programs. This automatic motor activation can occur both for higher level (i.e., the goal of an action) and for lower level (i.e., the specific effector with which it is executed) aspects of an action. The authors used a tool-use action paradigm to experimentally dissociate priming effects for observing the target, the movement, or the target-to-movement mapping of a tool-use action. In 3 experiments, participants took turns in acting, observing the tool-use action of another person in trial n-1, and executing an action in trial n. Trial transitions from n-1 to n were manipulated in 4 conditions with (a) mapping repeated and movement and target changed, (b) target repeated and movement and mapping changed, (c) movement repeated and target and mapping changed, or (d) all components repeated. Results indicate priming effects for repeating the target-to-movement mapping (i.e., the action rule) of a tool-use action and suggest that a rather abstract action schema is activated during action observation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
38.
探讨了造成Φ90mm圆盘延伸机前卡钢的原因,分析了轧件轧制过程中的第一、第二次咬入的受力情况,提出了预防前卡钢的措施。该措施实施后,基本消除了前卡钢现象。 相似文献
39.
适用于实时协同编著系统的并发控制研究 总被引:5,自引:0,他引:5
实时协同编著系统是最受欢迎的实时CSCW应用系统之一,适用于实时协同编著系统的并发控制用于解决参与协同工作用户对共享对象操作时存在的冲突问题。本文对这种新的并发控制与适用于分布式数据库系统等的传统并发控制进行了比较,讨论了一些适用于实时协同编著系统并发控制方法的新评价参数,分析了传统并发控制方法应用到实时协同编著系统时所遇到的问题。最后,我们介绍了一些文献中已有原型系统所使用的并发控制方法。 相似文献
40.
钛酸酯催化环氧树脂固化动力学研究 总被引:6,自引:2,他引:4
用FTIR“原位”技术,研究了钛酸酯(Tc-114)偶联剂对环氧E-44和二氨基二苯基甲烷(DDM)固化反应的催化作用,得出固化程度与时间的关系曲线。又根据DSC曲线,分别算出加有Tc-114和不加Tc-114的两个固化体系的反应表观活化能和反应级数。结果表明,Tc-114的存在使环氧固化反应活化能降低,催化作用明显。 相似文献