全文获取类型
收费全文 | 1527篇 |
免费 | 72篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 341篇 |
金属工艺 | 20篇 |
机械仪表 | 27篇 |
建筑科学 | 40篇 |
矿业工程 | 1篇 |
能源动力 | 23篇 |
轻工业 | 180篇 |
水利工程 | 6篇 |
石油天然气 | 1篇 |
无线电 | 202篇 |
一般工业技术 | 193篇 |
冶金工业 | 388篇 |
原子能技术 | 18篇 |
自动化技术 | 150篇 |
出版年
2023年 | 14篇 |
2022年 | 50篇 |
2021年 | 58篇 |
2020年 | 22篇 |
2019年 | 21篇 |
2018年 | 24篇 |
2017年 | 34篇 |
2016年 | 40篇 |
2015年 | 28篇 |
2014年 | 32篇 |
2013年 | 54篇 |
2012年 | 56篇 |
2011年 | 61篇 |
2010年 | 52篇 |
2009年 | 49篇 |
2008年 | 41篇 |
2007年 | 56篇 |
2006年 | 39篇 |
2005年 | 41篇 |
2004年 | 39篇 |
2003年 | 29篇 |
2002年 | 36篇 |
2001年 | 20篇 |
2000年 | 23篇 |
1999年 | 35篇 |
1998年 | 106篇 |
1997年 | 81篇 |
1996年 | 43篇 |
1995年 | 42篇 |
1994年 | 30篇 |
1993年 | 35篇 |
1992年 | 18篇 |
1991年 | 14篇 |
1990年 | 17篇 |
1989年 | 16篇 |
1988年 | 8篇 |
1987年 | 15篇 |
1986年 | 8篇 |
1985年 | 21篇 |
1984年 | 7篇 |
1983年 | 14篇 |
1981年 | 17篇 |
1980年 | 11篇 |
1979年 | 11篇 |
1978年 | 14篇 |
1977年 | 20篇 |
1976年 | 24篇 |
1975年 | 8篇 |
1973年 | 7篇 |
1971年 | 7篇 |
排序方式: 共有1600条查询结果,搜索用时 31 毫秒
181.
This paper assesses Concurrent Pascal against its design aims. The language is shown to be suitable for writing reliable non-trivial concurrent applications programs and operating systems. The major weakness of the language is its inability to provide an environment for other Concurrent Pascal programs. A new language construct, group, is proposed to remedy this difficulty. 相似文献
182.
Static brain images in a patient with subdural empyema showed findings similar to those of a subdural hematoma. The rapid-sequence study, however, showed increased peripheral activity on the affected side. Since this finding suggested an inflammatory process, further neuroradiologic evaluation and immediate surgical treatment were undertaken. The significance of the rapid-sequence study in subdural empyema has not been reported previously. 相似文献
183.
184.
AB Houston NL Gregory A Shaw DJ Wheatley EN Coleman 《Canadian Metallurgical Quarterly》1977,39(10):1071-1075
A wide angle (60 degrees) sector scanner producing a real-time two-dimensional echocardiogram has been used to examine healthy infants, children, and adults. Its method of use is described and findings from longitudinal and transverse scans are presented. The points of difference between the various types of electronic and mechanical two-dimensional scanning systems are discussed. This equipment minimises problems of chest contact and rib and lung interference and, by providing echocardiograms of high line density from a wide angle, is a suitable real-time two-dimensional scanning system for examining patients of all ages. 相似文献
185.
Carpenter J. Tyler; Coleman Michael J.; Waternaux Christine M.; Perry Jonathan; Wong Hazel; O'Brian Carita; Holzman Philip S. 《Canadian Metallurgical Quarterly》1993,5(1):75
Investigated whether short forms of the Rorschach Test are as effective as the standard 10-card administration in eliciting thought disorder as measured by the Thought Disorder Index. Results showed the short 4-card forms yield excellent composite indexes of total thought disorder, severity levels, and the more frequently occurring qualitative scores. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
186.
T. M. Cockerill D. V. Forbes H. Han B. A. Turkot J. A. Dantzig I. M. Robertson J. J. Coleman 《Journal of Electronic Materials》1994,23(2):115-119
Selective-area growth and regrowth using conventional atmospheric pressure metalorganic chemical vapor deposition is investigated for wavelength tuning in strained layer InxGa1-xAsGaAs-Aly Ga1-yAs quantum well lasers. Growth inhibition from a silicon dioxide mask is the mechanism used for the selective-area growth rate enhancement. By varying the width of the oxide stripe opening, differences in the growth rate yield different quantum well thicknesses, and hence different lasing wavelengths for devices on the same wafer. Both two-and three-step growth processes are utilized for selective-area epitaxy of strained layer InxGa1-xAs-GaAs quantum well active regions, with lasers successfully fabricated from the three-step growth. Scanning electron microscopy and transmission electron microscopy indicate that the absence of an oxide mask during AlyGa1-yAs growth is essential for successful device operation. A wide wavelength tuning range of over 630Å is achieved for lasers grown on the same substrate. 相似文献
187.
Beaver R. Coleman A. Draheim D. Hoffman A. 《Semiconductor Manufacturing, IEEE Transactions on》1994,7(2):127-133
This article describes the configurable MMST (Microelectronics Manufacturing Science and Technology) machine control architecture. The architecture has been developed to allow for quick insertion into current fabrication facilities while also allowing for a complete bottoms-up implementation of the machine control software. The MMST machine control is specifically designed to work with the next generation of vacuum-processing cluster tools currently under development by semiconductor equipment vendors and provides a windows based, graphical control panel for the equipment user 相似文献
188.
Jastreboff Pawel J.; Brennan James F.; Coleman John K.; Sasaki Clarence T. 《Canadian Metallurgical Quarterly》1988,102(6):811
To measure tinnitus induced by sodium salicylate injections, 84 rats were used in a conditioned suppression paradigm. In Exp 1, Ss were trained with a conditioned stimulus/stimuli (CS) consisting of the offset of a continuous background noise. One group began salicylate injections before Pavlovian training, a 2nd group started injections after training, and a control group received daily saline injections. Resistance to extinction was profound when injections started before training but minimal when initiated after training, suggesting that salicylate-induced effects acquired differential conditioned value. In Exp 2, salicylate treatments were mimicked by substituting a 7 kHz tone in place of respective injections, resulting in effects equivalent to salicylate-induced behavior. A 3rd experiment included a 3 kHz CS, and again replicated the salicylate findings. In Exp 4, we decreased the motivational level, and the sequential relation between salicylate-induced effects and suppression training was retained. Findings support the demonstration of phantom auditory sensations in animals. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
189.
190.
Jinchuan Chen Steven L Fales Gabriella A Varga Daniel J Royse 《Journal of the science of food and agriculture》1995,68(1):91-98
Treatment of crop residues with some species of white-rot fungi can enhance digestibility. This study was conducted to investigate changes in in-vitro dry matter disappearance (IVDMD) and degradation of cell wall constituents in maize (Zea maize L) stover treated with three white-rot fungi: Cyathus stercoreus, Phlebia brevispora and Phanerochaete chrysosporium. Solid fermentation of maize stover for 28 days at 27°C improved IVDMD from 409 g kg?1 (control) to 514 g kg?1 for P brevispora and 523 g kg?1 for C stercoreus. In contrast, growth of P chrysosporium reduced IVDMD from 409 to 298 g kg?1. All fungi degraded cell wall p-coumaric acid (PCA) and ferulic acid (FA), but P chrysosporium was the least effective in degrading PCA and FA. Conversely, P chrysosporium degraded lignin 1·6 times more effectively than C stercoreus and 1·4 times more than P brevispora, indicating that lignin degradation alone cannot account for the IVDMD enhancement and that degradation of PCA and FA may be important. Hemicelluloses were preferentially and highly utilized by all the fungi. Cellulose was extensively degraded only by P chrysosporium (69% lost after 28 days of incubation), while substrate colonized by the other two fungi retained more than 84% original cellulose. Incubation of C stercoreus and P brevispora decreased the concentrations of both xylose and arabinose, but increased glucose concentration, whereas P chrysosporium removed less xylose and decreased glucose concentration. Preferential removal of arabinose over xylose by the fungi caused an increase in the xylose to arabinose ratio of the treated residues. Enhanced digestibility may have resulted from cleavage of lignin-carbohydrate bonds. Results of this study suggest that digestibility enhancement of maize stover colonized by white-rot fungi is regulated by a complex combination of various factors, including the degradation of structural carbohydrates, cell wall phenolic acids and lignin. 相似文献