全文获取类型
收费全文 | 385篇 |
免费 | 25篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 65篇 |
金属工艺 | 12篇 |
机械仪表 | 8篇 |
建筑科学 | 13篇 |
矿业工程 | 1篇 |
能源动力 | 9篇 |
轻工业 | 32篇 |
水利工程 | 2篇 |
无线电 | 56篇 |
一般工业技术 | 74篇 |
冶金工业 | 48篇 |
原子能技术 | 1篇 |
自动化技术 | 85篇 |
出版年
2023年 | 6篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 8篇 |
2019年 | 9篇 |
2018年 | 18篇 |
2017年 | 18篇 |
2016年 | 17篇 |
2015年 | 10篇 |
2014年 | 22篇 |
2013年 | 33篇 |
2012年 | 30篇 |
2011年 | 31篇 |
2010年 | 26篇 |
2009年 | 25篇 |
2008年 | 23篇 |
2007年 | 20篇 |
2006年 | 15篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 14篇 |
2002年 | 11篇 |
2001年 | 4篇 |
2000年 | 4篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 6篇 |
1995年 | 2篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1984年 | 2篇 |
1982年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有410条查询结果,搜索用时 15 毫秒
61.
Enhanced goal‐oriented error assessment and computational strategies in adaptive reduced basis solver for stochastic problems
下载免费PDF全文
![点击此处可从《International journal for numerical methods in engineering》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Kevin Serafin Benoît Magnain Eric Florentin Núria Parés Pedro Díez 《International journal for numerical methods in engineering》2017,110(5):440-466
This work focuses on providing accurate low‐cost approximations of stochastic finite elements simulations in the framework of linear elasticity. In a previous work, an adaptive strategy was introduced as an improved Monte‐Carlo method for multi‐dimensional large stochastic problems. We provide here a complete analysis of the method including a new enhanced goal‐oriented error estimator and estimates of CPU (computational processing unit) cost gain. Technical insights of these two topics are presented in details, and numerical examples show the interest of these new developments. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
62.
Tian Gao Emmanuel Siéfert Antonio DeSimone Benoît Roman 《Advanced materials (Deerfield Beach, Fla.)》2020,32(47):2004515
Many active materials used in shape-morphing respond to an external stimulus by stretching or contracting along a director field. The programming of such actuators remains complex because of the single degree of freedom (the orientation) in local actuation. Here, texturing this field in zigzag patterns is shown to provide an extended family of biaxial active stretches out of an otherwise single uniaxial active deformation, opening a larger parameter space. By further modulating the zigzag patterns at the larger scale of the structure, its deployed shape can be controlled. This notion of texturing over hierarchical length scales follows geometrical principles, and is robust against changes in size and materials. The robustness of the approach is demonstrated by considering three different responsive materials: inextensible flat fabrics, channel-bearing elastomer (respectively, contracting and expanding perpendicularly to the director field when actuated pneumatically), and 3D-printed thermoplastic (composed of extruded filaments that contract when heated). It is shown that large-scale shape-morphing structures can be generated and that their geometry can be controlled with high accuracy. 相似文献
63.
Wireless Personal Communications - The wireless ad hoc networks impel the necessity for power control transmission based on interference aware to increase the throughput of the network and the... 相似文献
64.
Benoît Faugas Thomas Hawkins Courtney Kucera Klaus Bohnert John Ballato 《Journal of the American Ceramic Society》2018,101(9):4340-4349
Optical fibers possessing a crystalline oxide core have significant potential for novel and useful electro‐ or nonlinear‐optic waveguides. Presently, however, their utility suffers from the slow speed and limited cladding materials afforded by conventional crystal‐fiber‐growth techniques. Described herein is the development of single phase bismuth germanium oxide crystalline core fibers using conventional glass fiber drawing. More specifically, fibers were fabricated and evaluated based on 2 embodiments of the molten core method. In a first approach, a Bi4Ge3O12 single crystal was employed as the precursor and sleeved inside a borosilicate glass cladding. In the second approach, additional Bi2O3 was included along with the Bi4Ge3O12 precursor single crystal. Glass clad fibers drawn from the precursor Bi4Ge3O12 single crystal resulted in a polycrystalline core with various crystal morphologies (line‐like, dendrite‐like, and uniform grains) as will be discussed, while fibers drawn from the Bi4Ge3O12 single crystal surrounded by Bi2O3 resulted in a more homogeneous microstructure. The eulytine crystal structure was crystallized using both approaches, with the formation of a secondary crystal phase using the second approach. More particularly, this work aims at showing that single phase and phase pure crystalline oxide core optical fibers can be achieved using conventional glass fiber draw processes, although further optimization is necessary for obtaining single crystalline core fibers. 相似文献
65.
M. A. Sumesh S. P. Karanth Beno Thomas G. M. Rao M. Viswanathan P. Chakraborty G. N. Rao 《Journal of Infrared, Millimeter and Terahertz Waves》2017,38(2):135-142
Terahertz (THz) radiation perception using uncooled detectors are gaining importance due to the increasing demands in the areas of military, space, and industrial, medical, and surveillance applications. In spite of the efforts of researchers to fill the THz gap, there exists a need for detectors in the range between 15 THz and 30 THz. In this paper, we discuss the development of bolometric detectors whose performance is enhanced by an optical immersion technique and their characterization in the aforesaid range of frequencies. These detectors are characterized by high specific detectivity (D*) of 1.28?×?109 cmHz1/2 W?1 and high radiometric resolution (noise-equivalent temperature difference?=?26 mK) and are fast enough for bolometric detectors (time constant?=?1.7 ms), which make them suitable for spectroscopic and imaging applications. 相似文献
66.
Let f be an unknown multivariate density belonging to a set of densities \(\mathcal{F}_{k^{*}}\) of finite associated Vapnik–Chervonenkis dimension, where the complexity k * is unknown, and ? k ?? k+1 for all k. Given an i.i.d. sample of size n drawn from f, this article presents a density estimate \(\hat{f}_{K_{n}}\) yielding almost sure convergence of the estimated complexity K n to the true but unknown k * and with the property \(\mathbf{E}\{\int|\hat{f}_{K_{n}}-f|\}=\mbox{O}(1/\sqrt{n}\,)\). The methodology is inspired by the combinatorial tools developed in Devroye and Lugosi (Combinatorial methods in density estimation. Springer, New York, 2001) and it includes a wide range of density models, such as mixture models and exponential families. 相似文献
67.
Hu Z Muls B Gence L Serban DA Hofkens J Melinte S Nysten B Demoustier-Champagne S Jonas AM 《Nano letters》2007,7(12):3639-3644
We demonstrate that arrays of nanowires of conjugated polymers can be easily produced by a simple embossing protocol, compatible with very large scale integration technology. The embossing process is shown to have the supplementary virtue to increase the internal degree of order of the nanowires, significantly enhancing their performance. This is applied to the fabrication of nanowire-based devices consisting of a liquid crystalline light-emitting polymer, of a liquid crystalline semiconducting polymer, and of an amorphous conducting polymer, illustrating the versatility and wide applicability of the method. 相似文献
68.
Effects of deBDE and PCB-126 on hepatic concentrations of PBDEs and methoxy-PBDEs in Atlantic tomcod 总被引:1,自引:0,他引:1
The biotransformation of high bromosubstituted polybrominated diphenyl ethers (PBDEs) congeners contained in a commercial deca mixture (DeBDE) is of environmental concern because it might lead to the increase of toxic low brominated PBDEs in biota. A few studies have reported that freshwater fish dietary exposed to DeBDE or its main constituent, decabrominated PBDE congener (BDE-209), had their tissues enriched with PBDEs not initially present in fish or feed. In the present study, Atlantic tomcod (Microgadus tomcod) were intraperitoneally (IP) injected with DeBDE to assess hepatic concentration changes of PBDEs and methoxy polybrominated diphenyl ethers (MeO-PBDEs) in a marine fish species. Tomcod were also IP injected with polychlorinated biphenyl (PCB)-126 to evaluate the impact of cytochrome P4501A (CYP1A) induction on the biotransformation of injected PBDEs contained in DeBDE and PBDEs initially present in fish. Besides BDE-209, concentrations of BDE-203 and three other unidentified octabrominated PBDEs and the nonabrominated PBDEs (BDE-206, -207, and -208) were enriched in the liver of fish injected with DeBDE. All these PBDE congeners, essentially absent in control fish, were identified as impurities in DeBDE, and, thus, their presence could not be attributed exclusivelyto biotransformation. Despite a 4.3times increase of EROD activity in the liver of tomcod injected with both PCB-126 and DeBDE, compared to DeBDE alone, no further increases of PBDE hepatic concentrations were observed. However, depleted concentrations of BDE-17 (x 1.5) and 6-MeO-BDE-47 (x 1.4) were found in fish IP injected with DeBDE compared to control fish, likely due to activated hepatic metabolic enzymes other than CYP1A. Fish injected with PCB-126 showed an even more significant depletion of BDE-17 hepatic concentrations (x 3.5) than the one associated with the DeBDE treatment and a significantly lower proportion of fish with quantifiable concentrations of BDE-203. Thus, CYP1A inducers can promote the biotransformation of PBDEs in fish liver. This study shows that exposure of fish to DeBDE is expected to result in the enrichment of high brominated PBDEs in fish liver and that metabolic activities in fish can affect their PBDE bioaccumulation pattern and possibly the toxicity of PBDEs to fish. 相似文献
69.
Zitek Emily M.; Jordan Alexander H.; Monin Beno?t; Leach Frederick R. 《Canadian Metallurgical Quarterly》2010,98(2):245
Three experiments demonstrated that feeling wronged leads to a sense of entitlement and to selfish behavior. In Experiment 1, participants instructed to recall a time when their lives were unfair were more likely to refuse to help the experimenter with a supplementary task than were participants who recalled a time when they were bored. In Experiment 2, the same manipulation increased intentions to engage in a number of selfish behaviors, and this effect was mediated by self-reported entitlement to obtain positive (and avoid negative) outcomes. In Experiment 3, participants who lost at a computer game for an unfair reason (a glitch in the program) requested a more selfish money allocation for a future task than did participants who lost the game for a fair reason, and this effect was again mediated by entitlement. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
70.
Benoît Mazères Clara Desgranges Caroline Toffolon-Masclet Daniel Monceau 《Oxidation of Metals》2013,79(1-2):121-133
Previous studies have shown that the numerical model EKINOX-Zr was able to simulate with accuracy oxide growth and oxygen diffusion into the matrix during high-temperature oxidation of Zy-4. In this study, the aim of the development was to evaluate if the observed effect of hydrogen cladding content on the increase of oxygen solubility in the high-temperature βZr was only a thermodynamic effect. Previous experimental studies have shown that hydrogen induces an evolution of equilibrium oxygen concentration at the αZr/βZr interface. The present work showed that EKINOX-Zr linked with the thermodynamic database Zircobase reproduced the evolution induced by hydrogen during the high-temperature steam oxidation. However, the results showed also that additional studies are necessary to better understand hydrogen behavior during high-temperature oxidation of Zr. 相似文献