全文获取类型
收费全文 | 262篇 |
免费 | 10篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 67篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 3篇 |
能源动力 | 4篇 |
轻工业 | 25篇 |
石油天然气 | 3篇 |
无线电 | 16篇 |
一般工业技术 | 44篇 |
冶金工业 | 63篇 |
自动化技术 | 42篇 |
出版年
2023年 | 1篇 |
2022年 | 13篇 |
2021年 | 17篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 5篇 |
2016年 | 11篇 |
2015年 | 11篇 |
2014年 | 9篇 |
2013年 | 9篇 |
2012年 | 6篇 |
2011年 | 16篇 |
2010年 | 7篇 |
2009年 | 10篇 |
2008年 | 10篇 |
2007年 | 7篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 1篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 21篇 |
1997年 | 17篇 |
1996年 | 15篇 |
1995年 | 8篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 5篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有272条查询结果,搜索用时 31 毫秒
1.
2.
In this paper the response of nonlinear systems driven by parametric Poissonian white noise is examined.As is well known, the response sample function or the response statistics of a system driven by external white noise processes is completely defined. Starting from the system driven by external white noise processes, when an invertible nonlinear transformation is applied, the transformed system in the new state variable is driven by a parametric type excitation. So this latter artificial system may be used as a tool to find out the proper solution to solve systems driven by parametric white noises. In fact, solving this new system, being the nonlinear transformation invertible, we must pass from the solution of the artificial system (driven by parametric noise) to that of the original one (driven by external noise, that is known). Moreover, introducing this invertible nonlinear transformation into the Itô’s rule for the original system driven by external input, one can derive the Itô’s rule for systems driven by a parametric type excitation, directly. In this latter case one can see how natural is the presence of the Wong–Zakai correction term or the presence of the hierarchy of correction terms in the case of normal and Poissonian white noise, respectively. Direct transformation on the Fokker–Planck and on the Kolmogorov–Feller equation for the case of parametric input are found. 相似文献
3.
We have verified that chemotaxis of isolated human polymorphonuclear leukocytes (PMN) was a target of in vitro toxicant effect of acrylonitrile (ACN). This toxicant induced a significant dose dependent decreasing of chemotaxis with 50% inhibition (IC50) occurring at 15 mM. We assume that PMN from workers exposed to ACN reacts vivo in a similar way to PMN exposed in vitro to ACN. We propose therefore to use chemotaxis assay as a biomarker of early biological effect of ACN in workers, since for their monitoring there are so far only internal dose indicators but no suitable effect indicators. 相似文献
4.
Magorzata Zubielewicz Elbieta Kamiska-Tarnawska Antonina Kozowska 《Progress in Organic Coatings》2005,53(4):276-285
Investigations have been carried out on properties of coatings, differing by their pigmentation and binder, and applied on different chemical pre-treatments of the steel surface. Paints based on alkyd and alkyd-melamine binders, pigmented with zinc phosphate and modified basic zinc phosphate were applied on amorphous and crystalline phosphated steel surface and, for the comparison purpose, on degreased steel surface. The effect of the binder, the pigment and the pre-treatment of the steel surface on the protective properties of the coatings were determined by measurements of adhesion, water absorption and water permeability and by results obtained in salt spray and Prohesion tests. Coatings based on alkyd binder show a lower damage degree and good retention of adhesion in corrosion conditions, in spite of a higher water absorption and water permeability and a lower initial adhesive strength. Protective properties of coatings have been found to be highly dependent upon the substrate pre-treatment. Chemical pre-treatment of the steel substrate increases the protective properties of the system, which is particularly evident in the case of crystalline phosphating and the coating pigmented with modified basic zinc phosphate. This phenomenon can be explained by the synergism between this phosphate pigment with crystalline phosphate layer. 相似文献
5.
DellaGreca M Isidori M Lavorgna M Monaco P Previtera L Zarrelli A 《Journal of chemical ecology》2004,30(4):867-879
Twenty-five 9,10-dihydrophenanthrenes, four phenanthrenes, a dihydrodibenzoxepin, and a pyrene, isolated from the wetland plant Juncus acutus, were tested to detect their effects on the green alga Selenastrum capricornutum. Nine of the compounds were isolated and identified for the first time. Most of the compounds caused inhibition of algal growth. The 9,10-dihydrophenanthrenes 1, 5, 21, and 22 were the most active. 相似文献
6.
7.
8.
This paper presents the design of an open photoacoustic Helmholtz cell in which high acoustic volumes with quarter-wave ducts act as high-impedance separators between the main Helmholtz cell structure and the exterior. As a result, penetration of the external acoustic noise into the cell was substantially reduced in comparison to earlier open Helmholtz cell designs. Although the presented cell is not windowless, the photoacoustic background signal resulting from the absorption of the light by the windows is significantly lower in comparison to standard Helmholtz cells. Such an effect was obtained by locating the windows not at the relatively small sample cavity, but at the acoustic buffers, for which the volumes are two orders of magnitude higher. The proposed cell is dedicated for gas or liquid measurements, and its design allows for constant flow of the fluid. Hence, it can be used in continuous, real-time photoacoustic measurements. 相似文献
9.
10.
Dmitrii Iudin Marina Vasilieva Elena Knyazeva Viktor Korzhikov-Vlakh Elena Demyanova Antonina Lavrentieva Yury Skorik Evgenia Korzhikova-Vlakh 《International journal of molecular sciences》2022,23(5)
The growing number of drug-resistant pathogenic bacteria poses a global threat to human health. For this reason, the search for ways to enhance the antibacterial activity of existing antibiotics is now an urgent medical task. The aim of this study was to develop novel delivery systems for polymyxins to improve their antimicrobial properties against various infections. For this, hybrid core–shell nanoparticles, consisting of silver core and a poly(glutamic acid) shell capable of polymyxin binding, were developed and carefully investigated. Characterization of the hybrid nanoparticles revealed a hydrodynamic diameter of approximately 100 nm and a negative electrokinetic potential. The nanoparticles demonstrated a lack of cytotoxicity, a low uptake by macrophages, and their own antimicrobial activity. Drug loading and loading efficacy were determined for both polymyxin B and E, and the maximal loaded value with an appropriate size of the delivery systems was 450 µg/mg of nanoparticles. Composite materials based on agarose hydrogel were prepared, containing both the loaded hybrid systems and free antibiotics. The features of polymyxin release from the hybrid nanoparticles and the composite materials were studied, and the mechanisms of release were analyzed using different theoretical models. The antibacterial activity against Pseudomonas aeruginosa was evaluated for both the polymyxin hybrid and the composite delivery systems. All tested samples inhibited bacterial growth. The minimal inhibitory concentrations of the polymyxin B hybrid delivery system demonstrated a synergistic effect when compared with either the antibiotic or the silver nanoparticles alone. 相似文献