全文获取类型
收费全文 | 1697篇 |
免费 | 18篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 118篇 |
金属工艺 | 8篇 |
机械仪表 | 10篇 |
建筑科学 | 34篇 |
矿业工程 | 2篇 |
能源动力 | 14篇 |
轻工业 | 102篇 |
水利工程 | 10篇 |
石油天然气 | 2篇 |
无线电 | 73篇 |
一般工业技术 | 136篇 |
冶金工业 | 1095篇 |
原子能技术 | 8篇 |
自动化技术 | 94篇 |
出版年
2022年 | 11篇 |
2021年 | 16篇 |
2020年 | 15篇 |
2019年 | 20篇 |
2018年 | 7篇 |
2017年 | 15篇 |
2016年 | 13篇 |
2015年 | 19篇 |
2014年 | 14篇 |
2013年 | 45篇 |
2012年 | 24篇 |
2011年 | 23篇 |
2010年 | 26篇 |
2009年 | 17篇 |
2008年 | 28篇 |
2007年 | 26篇 |
2006年 | 19篇 |
2005年 | 24篇 |
2004年 | 16篇 |
2003年 | 19篇 |
2002年 | 23篇 |
2001年 | 15篇 |
2000年 | 15篇 |
1999年 | 50篇 |
1998年 | 281篇 |
1997年 | 187篇 |
1996年 | 121篇 |
1995年 | 76篇 |
1994年 | 80篇 |
1993年 | 70篇 |
1992年 | 24篇 |
1991年 | 24篇 |
1990年 | 25篇 |
1989年 | 32篇 |
1988年 | 25篇 |
1987年 | 24篇 |
1986年 | 24篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 13篇 |
1980年 | 11篇 |
1979年 | 7篇 |
1977年 | 31篇 |
1976年 | 51篇 |
1975年 | 6篇 |
1973年 | 8篇 |
1970年 | 8篇 |
1968年 | 6篇 |
排序方式: 共有1716条查询结果,搜索用时 15 毫秒
71.
72.
73.
Harding CM Lane RG 《Journal of the Optical Society of America. A, Optics, image science, and vision》2002,19(2):295-305
The paper describes a volumetric approach to depth estimation for robot navigation with use of only an approximately calibrated translating camera. Our approach is related to techniques for photo-realistic object reconstruction but with the emphasis on issues associated with navigation. The technique performs three-dimensional matching by a process of image interpolation and can adjust for errors in camera position. The reconstruction is achieved from a small angular range of scene views, and the technique is demonstrated to be insensitive to large errors in the camera positions. The ability to correct for more critical errors such as the camera orientation is shown to significantly improve the algorithm's performance. Our technique is demonstrated on real image sequences and compares favorably with techniques based on optical flow. 相似文献
74.
Surface-enhanced Raman scattering from individual au nanoparticles and nanoparticle dimer substrates 总被引:1,自引:0,他引:1
Talley CE Jackson JB Oubre C Grady NK Hollars CW Lane SM Huser TR Nordlander P Halas NJ 《Nano letters》2005,5(8):1569-1574
Surface-enhanced Raman scattering (SERS) intensities for individual Au nanospheres, nanoshells, and nanosphere and nanoshell dimers coated with nonresonant molecules are measured, where the precise nanoscale geometry of each monomer and dimer is identified through in situ atomic force microscopy. The observed intensities correlate with the integrated quartic local electromagnetic field calculated for each specific nanostructure geometry. In this study, we find that suitably fabricated nanoshells can provide SERS enhancements comparable to nanosphere dimers. 相似文献
75.
Hull Rachel; Martin Randi C.; Beier Margaret E.; Lane David; Hamilton A. Cris 《Canadian Metallurgical Quarterly》2008,22(4):508
Confirmatory factor analysis (CFA) and structural equation modeling (SEM) were used to study the organization of executive functions in older adults. The four primary goals were to examine (a) whether executive functions were supported by one versus multiple underlying factors, (b) which underlying skill(s) predicted performance on complex executive function tasks, (c) whether performance on analogous verbal and nonverbal tasks was supported by separable underlying skills, and (d) how patterns of performance generally compared with those of young adults. A sample of 100 older adults completed 10 tasks, each designed to engage one of three control processes: mental set shifting (Shifting), information updating or monitoring (Updating), and inhibition of prepotent responses (Inhibition). CFA identified robust Shifting and Updating factors, but the Inhibition factor failed to emerge, and there was no evidence for verbal and nonverbal factors. SEM showed that Updating was the best predictor of performance on each of the complex tasks the authors assessed (the Tower of Hanoi and the Wisconsin Card Sort). Results are discussed in terms of insight for theories of cognitive aging and executive function. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
76.
77.
78.
79.
In this study, the authors evaluated the effects of a brief personal construct group therapy on breast cancer survivors (N = 42) randomly assigned to either the treatment or wait-list control condition. The Gottschalk Gleser Content Analysis Scales were used to measure the effects for group across time (preand posttreatment, pretreatment, and 3-month posttreatment) on the personal construct states of threat, threat to existence, dislocation, and hope. Analyses showed that the beneficial effects of therapy achieved posttreatment were maintained at 3-month follow-up. The therapeutic group factors (I. D. Yalom, 1995) identified by the therapy group members as helpful in achieving these outcomes are also reported. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
80.