全文获取类型
收费全文 | 991篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 13篇 |
综合类 | 3篇 |
化学工业 | 262篇 |
金属工艺 | 29篇 |
机械仪表 | 16篇 |
建筑科学 | 32篇 |
能源动力 | 33篇 |
轻工业 | 73篇 |
水利工程 | 5篇 |
石油天然气 | 1篇 |
无线电 | 137篇 |
一般工业技术 | 185篇 |
冶金工业 | 44篇 |
原子能技术 | 16篇 |
自动化技术 | 145篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 11篇 |
2020年 | 8篇 |
2019年 | 15篇 |
2018年 | 10篇 |
2017年 | 11篇 |
2016年 | 8篇 |
2015年 | 5篇 |
2014年 | 27篇 |
2013年 | 56篇 |
2012年 | 48篇 |
2011年 | 53篇 |
2010年 | 51篇 |
2009年 | 56篇 |
2008年 | 52篇 |
2007年 | 46篇 |
2006年 | 46篇 |
2005年 | 43篇 |
2004年 | 25篇 |
2003年 | 31篇 |
2002年 | 36篇 |
2001年 | 12篇 |
2000年 | 14篇 |
1999年 | 23篇 |
1998年 | 22篇 |
1997年 | 16篇 |
1996年 | 18篇 |
1995年 | 22篇 |
1994年 | 17篇 |
1993年 | 8篇 |
1992年 | 15篇 |
1991年 | 8篇 |
1990年 | 9篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 13篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 11篇 |
1983年 | 8篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 14篇 |
1979年 | 6篇 |
1977年 | 4篇 |
1976年 | 9篇 |
1975年 | 6篇 |
1974年 | 7篇 |
1971年 | 5篇 |
排序方式: 共有994条查询结果,搜索用时 0 毫秒
11.
Given r≥n quasi-homogeneous polynomials in n variables, the existence of a certain duality is shown and made explicit in terms of generalized Morley forms. This result, that can be seen as a generalization of [Corollary 3.6.14, Jouanolou, J.-P., 1996. Résultant anisotrope, compléments et applications. Electron. J. Combin. 3 (2), Research Paper 2, approx. 91 pp. (electronic), the Foata Festschrift] where this duality is proved in the case r=n, was observed by the author at the same time. We will actually closely follow the proof of the above-cited corollary in this paper. 相似文献
12.
13.
14.
Christophe Fiter Laurentiu Hetel Wilfrid Perruquetti Jean-Pierre Richard 《Automatica》2012,48(8):1860-1867
In this work, a new state-dependent sampling control enlarges the sampling intervals of state feedback control. We consider the case of linear time invariant systems and guarantee the exponential stability of the system origin for a chosen decay rate. The approach is based on LMIs obtained thanks to sufficient Lyapunov–Razumikhin stability conditions and follows two steps. In the first step, we compute a Lyapunov–Razumikhin function that guarantees exponential stability for all time-varying sampling intervals up to some given bound. This value can be used as a lower-bound of the state-dependent sampling function. In a second step, an off-line computation provides a mapping from the state-space into the set of sampling intervals: the state is divided into a finite number of regions, and to each of these regions is associated an allowable upper-bound of the sampling intervals that will guarantee the global (exponential or asymptotic) stability of the system. The results are based on sufficient conditions obtained using convex polytopes. Therefore, they involve some conservatism with respect to necessary and sufficient conditions. However, at each of the two steps, an optimization on the sampling upper-bounds is proposed. The approach is illustrated with numerical examples from the literature for which the number of actuations is shown to be reduced with respect to the periodic sampling case. 相似文献
15.
Adnane Hamiaz Rudy Klein Xavier Ferrieres Olivier Pascal Jean-Pierre Boeuf Jean-Rene Poirier 《Computer Physics Communications》2012,183(8):1634-1640
The modelling of plasma formation during microwave breakdown is a difficult task because of the strong non-linear coupling between Maxwell?s equations and plasma equations, and of the large plasma density gradients that form during breakdown. An original Finite Volume Time Domain (FVTD) method has been developed to solve Maxwell?s equations coupled with a simplified fluid plasma model and is described in this paper. This method is illustrated with the study of the shielding of a metallic aperture by the plasma generated by an incident high power electromagnetic wave. Typical results obtained with the FVTD method for this shielding problem are shown. 相似文献
16.
We consider the problem of predictive control of uncertain stochastic discrete I/O systems. Given a model identification procedure able to give accurate output system estimates, e.g. a neural network approximation, we use another feedforward neural network to generate at each time step a constrained optimal control. Dynamic backpropagation is used to improve when necessary the controller network parameters. Both system and controller neural structures are first selected off-line by a statistical Bayesian procedure in order to make the predictive control minimizing process more efficient. The issue of stochastic stability of the closed-loop is considered. We developed this approach for the tracking control of such uncertain systems as biotechnological processes. Actual and simulated predictive neuro-control case studies in this field of application are proposed as illustrations. A comparison with a more classic quasi-Newton-based approach is also proposed, showing the interest of this neuro-control approach. 相似文献
17.
Diguer Louis; Pelletier Sylvie; Hébert étienne; Desc?teaux Jean; Rousseau Jean-Pierre; Daoust Jean-Philippe 《Canadian Metallurgical Quarterly》2004,21(2):259
This study examined the hypothesis that psychotic, borderline, and neurotic personality organizations (POs) present a progressive differentiation between self and object representations and an increasing integration of their bad and good aspects. Fifty patients participated in the study. Measures included scales of self and object representations (S. J. Blatt, S. A. Bers, & C. E. Schaffer, 1993; S. J. Blatt, H. Wiseman, E. Prince-Gibson, & C. Gatt, 1991), as well as the Personality Organization Diagnostic Form (L. Diguer & L. Normandin, 1997) and estimations of psychiatric severity. Results showed that PO groups differed in terms of the integration of the object and its valence. It was also observed that although object and self representations were closely intertwined, the latter showed more discrimination between POs than the former. Psychiatric severity was shown to correlate more with object representations than self representations. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
18.
Guillermo A. Oliveira Udry Laura Tiessler-Sala Eva Pugliese Agathe Urvoas Zakaria Halime Jean-Didier Marchal Jean-Pierre Mahy Rmy Ricoux 《International journal of molecular sciences》2022,23(23)
The covalent insertion of a cobalt heme into the cavity of an artificial protein named alpha Rep (αRep) leads to an artificial cobalt hemoprotein that is active as a catalyst not only for the photo-induced production of H2, but also for the reduction of CO2 in a neutral aqueous solution. This new artificial metalloenzyme has been purified and characterized by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS), circular dichroism, and UltraViolet–Visible spectroscopy. Using theoretical experiments, the structure of this biohybrid and the positioning of the residues near the metal complex were examined, which made it possible to complete the coordination of the cobalt ion by an axial glutamine Gln283 ligand. While the Co(III)–porphyrin catalyst alone showed weak catalytic activity for both reactions, 10 times more H2 and four times more CO2 were produced when the Co(III)–porphyrin complex was buried in the hydrophobic cavity of the protein. This study thus provides a solid basis for further improvement of these biohybrids using well-designed modifications of the second and outer coordination sphere by site-directed mutagenesis of the host protein. 相似文献
19.
Jean-Pierre Reveillès Denis Richard 《Annals of Mathematics and Artificial Intelligence》1996,16(1):89-152
This paper gives a perfect, ideal, discretization of continuous notions. This is a very convenient frame to treat continuous problems or theories with the help of a computer. This is illustrated by the conversion of algorithms using real numbers into algorithms using integers only and the founding of discrete geometry. 相似文献
20.
Inmaculada Posadas Laura Romero-Castillo Rosa-Anna Ronca Andrii Karpus Serge Mignani Jean-Pierre Majoral Maringeles Muoz-Fernndez Valentín Cea 《International journal of molecular sciences》2022,23(8)
Nanoparticles are playing an increasing role in biomedical applications. Excitotoxicity plays a significant role in the pathophysiology of neurodegenerative diseases, such as Alzheimer’s or Parkinson’s disease. Glutamate ionotropic receptors, mainly those activated by N-methyl-D-aspartate (NMDA), play a key role in excitotoxic death by increasing intraneuronal calcium levels; triggering mitochondrial potential collapse; increasing free radicals; activating caspases 3, 9, and 12; and inducing endoplasmic reticulum stress. Neutral phosphorous dendrimers, acting intracellularly, have neuroprotective actions by interfering with NMDA-mediated excitotoxic mechanisms in rat cortical neurons. In addition, phosphorous dendrimers can access neurons inside human brain organoids, complex tridimensional structures that replicate a significant number of properties of the human brain, to interfere with NMDA-induced mechanisms of neuronal death. Phosphorous dendrimers are one of the few nanoparticles able to gain access to the inside of neurons, both in primary cultures and in brain organoids, and to exert pharmacological actions by themselves. 相似文献