全文获取类型
收费全文 | 312篇 |
免费 | 11篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 128篇 |
金属工艺 | 8篇 |
机械仪表 | 3篇 |
建筑科学 | 8篇 |
能源动力 | 2篇 |
轻工业 | 34篇 |
水利工程 | 6篇 |
无线电 | 16篇 |
一般工业技术 | 63篇 |
冶金工业 | 9篇 |
原子能技术 | 10篇 |
自动化技术 | 34篇 |
出版年
2022年 | 12篇 |
2021年 | 12篇 |
2020年 | 6篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 9篇 |
2015年 | 5篇 |
2014年 | 12篇 |
2013年 | 29篇 |
2012年 | 14篇 |
2011年 | 11篇 |
2010年 | 12篇 |
2009年 | 14篇 |
2008年 | 10篇 |
2007年 | 12篇 |
2006年 | 9篇 |
2005年 | 14篇 |
2004年 | 13篇 |
2003年 | 5篇 |
2002年 | 9篇 |
2001年 | 7篇 |
2000年 | 2篇 |
1999年 | 7篇 |
1998年 | 4篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1994年 | 5篇 |
1993年 | 3篇 |
1992年 | 5篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1980年 | 2篇 |
1977年 | 2篇 |
1976年 | 4篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1965年 | 2篇 |
1941年 | 2篇 |
1937年 | 2篇 |
1936年 | 1篇 |
排序方式: 共有323条查询结果,搜索用时 15 毫秒
61.
Imre Zólomy 《Solid-state electronics》1985,28(6):537-547
A basic concept of bipolar amplifying devices as well as of negative-resistance devices is formulated. With the aid of this scheme a systematic survey is given for already reported and for possible new amplifying and negative-resistance devices, starting from five basic effects: the pn junction, the metal-(tunnel oxide)-semiconductor diode, the Schottky barrier, the bulk-barrier and the avalanche multiplication. Selecting two of these mechanisms and combining them into a feedback loop, a wide variety of negative-resistance devices can be constructed. Structures with more than two amplifying mechanisms are also briefly considered. 相似文献
62.
Imre A. Varga E. Ji L. Ilic B. Metlushko V. Csaba G. Orlov A. Bernstein G.H. Porod W. 《IEEE transactions on magnetics》2006,42(11):3641-3644
Ferromagnetic ring elements on the micrometer and submicrometer scale exhibit flux-closure magnetic vortex states in an intermediate step of their magnetization reversal. These clockwise or counterclockwise flux-closure states are of interest for applications that encode binary information in magnetic elements. Here, we study the magnetization reversal process of triangular cobalt rings made by e-beam lithography and lift-off. We demonstrate that full control over the direction of flux-closure magnetic states can be achieved solely by homogeneous external magnetic fields applied in particular directions. We have extracted statistical experimental data pertaining to the range of critical field values that trigger magnetization reversal from magnetic force microscopy images, and we explain the results on the basis of micromagnetic simulations 相似文献
63.
Summary The effect of polymer precipitation that occurs during polymerization on the number average molecular weight ¯Mn has been investigated in conjunction with the recently described trans-2,5-diacetoxy-2,5-dimethyl-3-hexene (DiAcODMH6)/BCl3/isobutylene(IB)/CH3Cl/- 35° system using both the IMA and AMI techniques. All the experimental data could be described by a common rectilinear l/¯Mn versus l/Wp (Wp = weight of polymer) plot exhibiting an intercept l/¯Mn,max. A simple equation has been derived that explains quantitatively the results and suggests that product molecular weights obtained in heterogeneous polymerizations are determined by polymer precipitation which in turn leads to chain transfer. An Arrhenius analysis of ¯Mn,max values obtained at various temperatures corroborates this proposition and suggests polymer precipitation to control ¯Mn. That precipitation conditions determine ¯Mn seem also to hold true for conventional AlCl3-induced IB polymerizations.Papers XXI of this series will appear in Polymer Preprints, R. Faust and J.P. Kennedy, 29(2), 1988 相似文献
64.
Possibilities of means of dilatometry in connection with production of multiphase (DP- and TRIP-) steels were examined in detail. These steels are characterized by an excellent combination of high strength and good press formability,which are essentially important in the automotive industry. Transformation processes, cooling rates, holding temperatures,composition and technological parameters play a very important role in formation of applicable microstructure of multiphase steels. Dilatometrical experiments were carried out to study the processes of intercritical annealing and hot rolling of several DP- and TRIP-steels. 相似文献
65.
We prove the secret key rate formulas and derive security threshold parameters of multicarrier continuous‐variable quantum key distribution CVQKD. In a multicarrier CVQKD scenario, the Gaussian input quantum states of the legal parties are granulated into Gaussian subcarrier continuous variables (CVs). The multicarrier communication formulates Gaussian subchannels from the physical quantum channel, each dedicated to the transmission of a subcarrier CV. The Gaussian subcarriers are decoded by a unitary CV operation, which results in the recovered single‐carrier Gaussian CVs. We derive the formulas through the adaptive multicarrier quadrature division (AMQD) scheme, the singular value decomposition (SVD)–assisted AMQD, and the multiuser AMQD multiuser quadrature allocation (MQA). We prove that the multicarrier CVQKD leads to improved secret key rates and higher tolerable excess noise in comparison with single‐carrier CVQKD. We derive the private classical capacity of a Gaussian subchannel and the security parameters of an optimal Gaussian collective attack in the multicarrier setting. We reveal the secret key rate formulas for one‐way and two‐way multicarrier CVQKD protocols, assuming homodyne and heterodyne measurements and direct and reverse reconciliation. The results reveal the physical boundaries of physically allowed Gaussian attacks in a multicarrier CVQKD scenario and confirm that the improved transmission rates lead to enhanced secret key rates and security thresholds. 相似文献
66.
Farhad Faraji Imre Safarik Otto P. Strausz Erdal Yildirim Manuel E. Torres 《加拿大化工杂志》1999,77(1):78-84
The pyrolysis of COS has been studied over the temperature range 300 to 750°C using a variety of catalysts. The observed product distribution confirmed that two parallel reaction paths: 2 COS → 2 CO S2 (2) and 2 COS → CO2 + CS2 (4) are involved in the decomposition. The decomposition yield increased with rising temperature, accompanied with a shift in selectivity. At temperatures lower than ~700°C the disproportionation reaction 4 was predominant, whereas at temperatures higher than 700°C, reaction 2 was favoured. In the high-temperature region (700 to 750°C) it was possible to achieve full suppression of reaction 4 with added CS2. The pyrolysis of COS was also studied in a reactor packed with quartz chips without catalysts at high temperatures. Between 800 and 900°C, up to 99% conversion (with respect to the thermodynamic limit) could be achieved, with the almost complete absence of the disproportionation reaction 4. The results point to the commercial potential in the two-step reaction sequence: for the economic conversion of hydrogen sulfide to hydrogen and sulfur. 相似文献
67.
68.
Computer engineers are continuously seeking new solutions to increase available processing speed, achievable transmission rates, and efficiency in order to satisfy users’ expectations. While multi-core systems, computing clouds, and other parallel processing techniques dominate current technology trends, elementary particles governed by quantum mechanics have been borrowed from the physicists’ laboratory and applied to computer engineering in the efforts to solve sophisticated computing and communications problems. In this paper, we review the quantum mechanical background of quantum computing from an engineering point of view and describe the possibilities offered by quantum-assisted and quantum-based computing and communications. In addition to the currently available solutions, the corresponding challenges will also be surveyed. 相似文献
69.
Szilvia Klébert Anna Mária Keszler István Sajó Eszter Drotár Imre Bertóti Eszter Bódis Péter Fazekas Zoltán Károly János Szépvölgyi 《Ceramics International》2014
Continuous synthesis of TiBx (x≈0.5–2) nanoparticles from various low cost solid precursors such as titanium and titanium dioxide admixed with boron and/or carbon in radiofrequency thermal plasma was studied. Feasibility of TiB2 formation was predicted by thermodynamic equilibrium calculations in the 500–5000 K temperature range. In all the investigated system high temperature reactions resulted in nanometer-sized TiBx powders with a mean size varying between 13 and 83 nm. The yield of particular runs ranged from 38% to 97%. Among the synthesized products in addition to TiBx, oxidized precursor residues were also found in smaller quantities. Although addition of carbon to the precursors could not completely prevent surface oxidation of boride particles, it contributed to the reduction of the mean particle size of the formed TiB2. 相似文献
70.
India's immense geography provides her with a variety of ambient energy resources. This paper examines the non-conventional energy sources and their possible future in India. While the non-conventional energy sources include geothermal energy, waves, tides and ocean thermal energy in addition to direct solar radiation, the emphasis in the paper is on solar, biomass and wind energy applications. Conventional energy sources including coal, oil, gas and nuclear energy are not going to be adequate and the alternative sources discussed are not going to be capable of fully replacing the above sources in any foreseeable future. While these alternative sources are likely to be only a partial substitute and not a total replacement, their contribution can usually be well above 50 per cent of the total energy needs. The energy profile of the country has also been discussed. 相似文献