全文获取类型
收费全文 | 1330篇 |
免费 | 18篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 52篇 |
金属工艺 | 13篇 |
机械仪表 | 3篇 |
建筑科学 | 30篇 |
能源动力 | 11篇 |
轻工业 | 37篇 |
水利工程 | 3篇 |
无线电 | 81篇 |
一般工业技术 | 68篇 |
冶金工业 | 984篇 |
原子能技术 | 4篇 |
自动化技术 | 56篇 |
出版年
2021年 | 5篇 |
2019年 | 6篇 |
2018年 | 12篇 |
2017年 | 9篇 |
2016年 | 5篇 |
2015年 | 8篇 |
2014年 | 12篇 |
2013年 | 35篇 |
2012年 | 12篇 |
2011年 | 19篇 |
2010年 | 10篇 |
2009年 | 8篇 |
2008年 | 12篇 |
2007年 | 13篇 |
2006年 | 16篇 |
2005年 | 14篇 |
2004年 | 8篇 |
2003年 | 15篇 |
2002年 | 13篇 |
2001年 | 10篇 |
2000年 | 9篇 |
1999年 | 32篇 |
1998年 | 259篇 |
1997年 | 167篇 |
1996年 | 115篇 |
1995年 | 78篇 |
1994年 | 51篇 |
1993年 | 58篇 |
1992年 | 14篇 |
1991年 | 17篇 |
1990年 | 21篇 |
1989年 | 22篇 |
1988年 | 33篇 |
1987年 | 16篇 |
1986年 | 15篇 |
1985年 | 21篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 15篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 25篇 |
1976年 | 63篇 |
1975年 | 5篇 |
1971年 | 6篇 |
1970年 | 3篇 |
1969年 | 4篇 |
1955年 | 3篇 |
排序方式: 共有1348条查询结果,搜索用时 0 毫秒
1.
2.
This study investigated the relationship between self-appraisals of performance, symptom severity and post-event rumination in social phobia, and evaluated the effect of treatment on these variables. A socially phobic group and a nonanxious control group performed an impromptu speech and were told that their performance would be evaluated. Participants appraised their performance immediately after the speech and 1 week later, and the frequency of post-event rumination during the week following the speech was assessed. The socially phobic group maintained the negative appraisals of their speech over the week, whereas the nonclinical group showed increased positivity about their performance The socially phobic group also engaged in more negative rumination than controls. Treatment improved perceptions of performance and reduced negative rumination. These results are discussed in the light of cognitive models of social phobia. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
3.
4.
Lopez J.F. Eshraghian K. Sarmiento R. Nunez A. Abbott D. 《Solid-State Circuits, IEEE Journal of》1997,32(8):1297-1303
A novel GaAs logic family, pseudodynamic latched logic (PDLL), is presented in this paper. It is composed of a dynamic circuit where the logic is performed and a static latch whose function is to permanently refresh the stored data on a dynamic node. Because of this hybrid structure, PDLL takes advantage of both static and dynamic families and thus, permits implementation of very complex structures with good speed-area power tradeoff. Moreover, the inclusion of the latch permits this class of logic family to be highly efficient for pipelined systems working even at high temperature without loss of data due to leakage currents. Barrel-shifters, programmable logic arrays (PLA's), and carry lookahead adders (CLA's) were verified by simulations demonstrating its feasibility for the development of high-performance very large scale integration (VLSI) systems 相似文献
5.
Learning navigational maps through potentiation and modulation of hippocampal place cells 总被引:1,自引:0,他引:1
We analyze a model of navigational map formation based on correlation-based, temporally asymmetric potentiation and depression of synapses between hippocampal place cells. We show that synaptic modification during random exploration of an environment shifts the location encoded by place cell activity in such a way that it indicates the direction from any location to a fixed target avoiding walls and other obstacles. Multiple maps to different targets can be simultaneously stored if we introduce target-dependent modulation of place cell activity. Once maps to a number of target locations in a given environment have been stored, novel maps to previously unknown target locations are automatically constructed by interpolation between existing maps. 相似文献
6.
7.
8.
LF Cooper 《Canadian Metallurgical Quarterly》1997,18(3):271-6, 278, 280-1; quiz 282
Modern restorative dentistry is confronted with many challenges related to implant use in the craniofacial region, such as attempting to place implants in esthetically critical sites or anatomically limiting regions of the jaw. To assure a successful implant placement that is satisfactory to both the patient and the dentist, four key areas need to be improved: diagnostic procedures, surgical procedures and outcomes, esthetic results, and prosthetic complications. This article discusses how an integrated approach to these areas can improve clinical practice. 相似文献
9.
10.