全文获取类型
收费全文 | 992篇 |
免费 | 63篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 9篇 |
化学工业 | 275篇 |
金属工艺 | 34篇 |
机械仪表 | 25篇 |
建筑科学 | 19篇 |
矿业工程 | 1篇 |
能源动力 | 37篇 |
轻工业 | 16篇 |
石油天然气 | 7篇 |
无线电 | 95篇 |
一般工业技术 | 319篇 |
冶金工业 | 89篇 |
原子能技术 | 13篇 |
自动化技术 | 121篇 |
出版年
2023年 | 17篇 |
2022年 | 41篇 |
2021年 | 52篇 |
2020年 | 21篇 |
2019年 | 38篇 |
2018年 | 39篇 |
2017年 | 34篇 |
2016年 | 46篇 |
2015年 | 36篇 |
2014年 | 35篇 |
2013年 | 58篇 |
2012年 | 74篇 |
2011年 | 76篇 |
2010年 | 45篇 |
2009年 | 60篇 |
2008年 | 53篇 |
2007年 | 47篇 |
2006年 | 51篇 |
2005年 | 38篇 |
2004年 | 31篇 |
2003年 | 28篇 |
2002年 | 25篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1994年 | 8篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1988年 | 2篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
1969年 | 1篇 |
1956年 | 1篇 |
1954年 | 2篇 |
排序方式: 共有1060条查询结果,搜索用时 15 毫秒
91.
Larisa I. Nasibulina Tatiana S. Koltsova Tuomo Joentakanen Albert G. Nasibulin Oleg V. Tolochko Jari E.M. Malm Maarit J. Karppinen Esko I. Kauppinen 《Carbon》2010,48(15):4559-4562
A novel approach to synthesize carbon nanofibers (CNFs) directly on the surface of metal μm-sized particles to evenly disperse the carbon nanomaterials in a composite material was proposed. As a metal matrix, 5–10 μm copper particles were utilized. As a carbon source, C2H2, CH4 and CO were examined. The best conditions were found to be in C2H2 (30 cm3/min) and H2 (260 cm3/min) atmosphere at the temperature of 750 °C. The composites based on copper and CNFs prepared by vacuum hot pressing showed the increase in hardness from 35 to 60 kg/mm2 almost retaining pure copper electrical properties. 相似文献
92.
Iaroslav G. Zhbankov Oleg E. Markov Alexander V. Perig 《The International Journal of Advanced Manufacturing Technology》2014,72(5-8):865-872
An upsetting process of specially profiled workpieces was proposed. Modeling of a workpiece upsetting, profiled as a cylinder with conical and cylindrical ledges was done using a finite element method. During the upsetting of these workpieces, buckling occurs. Schemes of upsetting a workpiece with conical ledges result in a decrease in the irregularity of the equivalent strain distribution in the longitudinal section. This scheme produces a zone of minimal equivalent strain decrease in the workpiece. It was found that during the upsetting process of the workpiece with a conical ledge on the lateral surface and in the center, compressive stresses appear. These stresses contribute to the closure of voids in an ingot during the upsetting process. Rational workpiece parameters were found which allow the production of forgings with minimal irregularity of equivalent strain distribution, minimal formation of a barrel, and a favorable stress state in the workpiece. Experimental research, which confirms the advantages of upsetting specially profiled workpieces, was done. 相似文献
93.
This paper proposes the Meissner-Ochsenfeld effect as a possible tool for quality control of type II superconductors (SC). Visual or optical inspection of the levitation process allows rough determination of the anisotropy of thermal conductivity and of the pinning strength of type II SC material, in a materials quality control. An assembly of permanent (e.g. NdFeB) or electromagnets and a flat cryostat allowing visual or optical inspection would be required. The method is demonstrated by numerically simulating the field cooling process of a superconducting cylindrical pellet and of a coated conductor. 相似文献
94.
Galina P. Kayukova Igor P. Kosachev Nikita V. Pronin Oleg S. Sotnikov Alexander М. Evdokimov 《Petroleum Science and Technology》2013,31(18):1463-1470
AbstractThe oil generating potential of Domanic rocks from Dankov–Lebedyan horizon of the Zelenogorsk area of Romashkino oil field was evaluated by Rock-Eval pyrolysis technique. The result of given method depends on the content, composition, and thermal stability of organic matter in rocks. During hydrothermal processes, the distinctive conversion behavior of organic matter at temperatures of 200°С, 250°С, 300°С, and 350°С in CO2 environment was revealed. The yield of obtained aquathermolysis products and their quality were evaluated. The results of the studies suggest that low-permeability carbonate rocks of the Dankov–Lebedyan horizon contain productive beds with content of Corg 1.89–3.03%, which when developed using thermal methods, can become an additional source of liquid hydrocarbons. 相似文献
95.
Mattia Gazzola Oleg V. Vasilyev Petros Koumoutsakos 《Computers & Structures》2011,89(11-12):1224-1231
We present results from the shape optimization of linked bodies for drag reduction in simulations of incompressible flow at moderate Reynolds numbers. The optimization relies on the covariance matrix adaptation evolution strategy (CMA-ES) and the flow simulations use vortex methods with the Brinkman penalization to enforce boundary conditions in complex bodies. We exploit the inherent parallelism of CMA-ES, by implementing a multi-host framework which allows for the distribution of the expensive cost function evaluations across parallel architectures, without being limited to one computing facility. This study repeats in silico for the first time Ingo Rechenberg’s pioneering wind tunnel experiments for drag reduction that led to the inception of evolution strategies. The simulations confirm that the results of these experimental studies indicate a flat plate is not the optimal solution for drag reduction in linked bodies. We present the vorticity field of the flow and identify the governing mechanisms for this drag reduction by the slightly corrugated linked plate configuration. 相似文献
96.
Doug Williams Marian F. Ursu Joshan Meenowa Pablo Cesar Ian Kegel Karl Bergström 《Telematics and Informatics》2011
This paper discusses results from research related to the use of television as a device that supports social interaction between close-knit groups in settings that include more than two locations, each location being potentially equipped with more than one camera. The paper introduces the notion of a framing experience, as a specific scenario or situation within which social communication takes place. It reports on the evaluation of some of the key attributes of social communication through semi-structured interviews, with 16 families across four European countries. The inferences drawn from this study are reduced to four system capabilities including the ability to support: excitement, engagement and entertainment; high quality, reliable audiovisual communications; flexibility and adaptability sufficient to support the unpredictable and reactive nature of human interaction and discourse. These system requirements are, in turn, reduced to a number of technology challenges which if solved will help enable effective social communications between groups, mediated by the television. These technology challenges include: high quality reliable audio visual communication; interaction orchestration, multimedia interpretation and multimedia composition. Finally the paper reflects on the impact the use of framing experiences, such as those described here, could have on strategy and policy for service providers and regulators. 相似文献
97.
98.
Raisa I. Belous Oleg I. Belous Yurii G. Makeev Alexander P. Motornenko 《Journal of Infrared, Millimeter and Terahertz Waves》1997,18(10):1991-1999
The method of the solution problem on the eigen oscillations spectrum of electromagnetic field in the waveguide-dielectric resonator with the two-layer dielectric element was presented. The numerical calculations of the resonance frequencies for theHE 111-,E 011- andH 011-oscillations types in the investigated structure were performed. The calculation results were correlated with experimental data. 相似文献
99.
100.
M. Bockstedte S. J. Liu Oleg Pankratov C. H. Woo Hanchen Huang 《Computational Materials Science》2002,23(1-4):85-94
The key factor determining nucleation processes and faceting in homoepitaxial growth as well as texture competition is the mobility of adatoms and small clusters across step edges and facets. Using a combination of molecular dynamics and ab initio calculations, we investigate the mechanisms of small clusters (dimer and trimer) diffusion down the aluminum (1 1 1) surface. In this paper we report results of molecular dynamics studies. Our study shows that the clusters dissociate at the step-edge of compact islands. As a result, the clusters diffuse down the step by an exchange mechanism with a small or medium Schwoebel barrier. The mechanism of this down-diffusion/dissociation is discussed and the corresponding energetics are calculated using the molecular statics method. We find a large anisotropy between the barriers at the two types of 1 1 0 oriented steps. 相似文献