全文获取类型
收费全文 | 390篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 75篇 |
金属工艺 | 2篇 |
机械仪表 | 6篇 |
建筑科学 | 7篇 |
能源动力 | 41篇 |
轻工业 | 39篇 |
石油天然气 | 2篇 |
无线电 | 56篇 |
一般工业技术 | 43篇 |
冶金工业 | 42篇 |
原子能技术 | 6篇 |
自动化技术 | 76篇 |
出版年
2024年 | 1篇 |
2023年 | 7篇 |
2022年 | 12篇 |
2021年 | 20篇 |
2020年 | 4篇 |
2019年 | 9篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 14篇 |
2015年 | 8篇 |
2014年 | 14篇 |
2013年 | 14篇 |
2012年 | 18篇 |
2011年 | 26篇 |
2010年 | 24篇 |
2009年 | 12篇 |
2008年 | 14篇 |
2007年 | 21篇 |
2006年 | 15篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 15篇 |
2002年 | 15篇 |
2001年 | 10篇 |
2000年 | 7篇 |
1999年 | 4篇 |
1998年 | 21篇 |
1997年 | 18篇 |
1996年 | 6篇 |
1995年 | 6篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1979年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 1篇 |
排序方式: 共有402条查询结果,搜索用时 0 毫秒
71.
Hamid Reza Shahhosseini Samrand Saeidi Sara Najari Fausto Gallucci 《International Journal of Hydrogen Energy》2017,42(31):19798-19809
Auto-thermal reforming (ATR), a combination of exothermic partial oxidation and endothermic steam reforming of methane, is an important process to produce syngas for petrochemical industries. In a commercial ATR unit, tubular fixed bed reactors are typically used. Pressure drop across the tube, high manufacturing costs, and low production capacity are some disadvantages of these reactors. The main propose of this study is to offer an optimized radial flow, spherical packed bed reactor as a promising alternative for overcoming the drawbacks of conventional tubular reactors. In the current research, a one dimensional pseudo-homogeneous model based on mass, energy, and momentum balances is applied to simulate the performance of packed-bed reactors for the production of syngas in both tubular and spherical reactors. In the optimization section, the proposed work explores optimal values of various decision variables that simultaneously maximize outlet molar flow rate of H2, CO and minimize molar flow rate of CO2 from novel spherical reactor. The multi-objective model is transformed to a single objective optimization problem by weighted sum method and the single optimum point is found by using genetic algorithm. The optimization results show that the pressure drop in the spherical reactor is negligible in comparison to that of the conventional tubular reactor. Therefore, it is inferred that the spherical reactor can operate with much higher feed flow rate, more catalyst loading, and smaller catalyst particles. 相似文献
72.
We explore tradeoffs between organization and number of ALUs and clock frequency in a stream processor. The tool provides candidate low-power configurations and estimates of their real-time performance. The tool relates instruction-level, subword, and data parallelism to functional units' organization and utilization. The exploration methodology is applicable to all embedded-processor designs in signal and media processing. 相似文献
73.
The use of chemically modified atomic force microscopy (AFM) probes allows us to measure the surface charges of supported planar lipid bilayers with high sensitivity through the force spectroscopy operation mode. By controlling the chemistry of the tip, we can perform a classical analytical chemistry titration where the titration agent is a weak acid (attached to the AFM tip) with the particularity of being performed in surface rather than in solution and, especially, at the nanometric scale. Thus, the AFM tip acts as a real "nanosensor". The approaching curves of the force plots reveal that electrostatic interactions between the tip and the supported membrane play a key role. Besides, the plot of the adhesion force (measured from the retracting curve of the force plots) versus pH displays a nonsigmoidal shape with a peak in the adhesion force attributed to high-energy hydrogen bonds. One of these peaks corresponds to the pKa of the surface under study and the other to the pKa of the titrating probe attached to the tip. 相似文献
74.
Modelling the Floating Ladder Track Response to a Moving Load by an Infinite Bernoulli-Euler Beam on Periodic Flexible Supports 下载免费PDF全文
Roger J. Hosking & Fausto Milinazzo 《East Asian journal on applied mathematics.》2012,2(4):285-308
An infinite Bernoulli-Euler beam (representing the "combined rail" consisting
of the rail and longitudinal sleeper) mounted on periodic flexible point supports
(representing the railpads) has already proven to be a suitable mathematical
model for the floating ladder track (FLT), to define its natural vibrations and its
forced response due to a moving load. Adopting deliberately conservative parameters
for the existing FLT design, we present further results for the response to a
steadily (uniformly) moving load when the periodic supports are assumed to be
elastic, and then introduce the mass and viscous damping of the periodic supports.
Typical support damping significantly moderates the resulting steady deflexion at
any load speed, and in particular substantially reduces the magnitude of the resonant
response at the critical speed. The linear mathematical analysis is then extended
to include the inertia of the load that otherwise moves uniformly along the
beam, generating overstability at supercritical speeds — i.e. at load speeds notably
above the critical speed predicted for the resonant response when the load inertia
is neglected. Neither the resonance nor the overstability should prevent the safe
implementation of the FLT design in modern high speed rail systems. 相似文献
75.
Fermented Nut‐Based Vegan Food: Characterization of a Home made Product and Scale‐Up to an Industrial Pilot‐Scale Production 下载免费PDF全文
76.
In LTE/LTE-A uplink receiver, frequency domain equalizers (FDE) are adopted to achieve good performance. However, in multi-tap channels, the residual inter-symbol and inter-antenna interference still exist after FDE and degrade the performance. Conventional interference cancellation schemes can minimize this interference by using frequency domain interference cancellation. However, those schemes have high complexity and large feedback latency, especially when adopting a large number of iterations. These result in low throughput and require a large amount of resource in software defined radio implementation. In this paper, we propose a novel low complexity interference cancellation scheme to minimize the residual interference in LTE/LTE-A uplink. Our proposed scheme can bring about 2 dB gains in different channels, but only adds up to 7.2 % complexity to the receiver. The scheme is further implemented on Xilinx FPGA. Compared to other conventional interference cancellation schemes, our scheme has less complexity, less data to store, and shorter feedback latency. 相似文献
77.
78.
Patrignani F Iucci L Vallicelli M Guerzoni ME Gardini F Lanciotti R 《Meat science》2007,75(4):676-686
The aim of this work was to study the effects of Debaryomyces hansenii and Yarrowia lipolytica strains, used with lactic acid starter cultures (Lactobacillus plantarum), on the manufacture of dried fermented sausages to understand their role on sausage microbial evolution, lipolytic and proteolytic patterns. The inoculation of the yeast strains did not markedly affect the sausage’s microbial flora. The sausages with the yeast strains showed more marked and earlier water activity (aw) reductions. Moreover, the surface inoculation of the yeast strains resulted, at the end of ripening, in more pronounced proteolysis and lipolysis. The lipolytic patterns of the products were affected not only by the yeast strain but also by the level of mincing of the meat mixture used. 相似文献
79.
Medina-Torres L Vernon-Carter EJ Gallegos-Infante JA Rocha-Guzman NE Herrera-Valencia EE Calderas F Jiménez-Alvarado R 《Journal of the science of food and agriculture》2011,91(6):1001-1005
BACKGROUND: The process of convective drying was evaluated in terms of the bioactive compounds contained in nopal samples before and after dehydration. Total polyphenol, flavonoid, flavonol, carotene and ascorbic acid contents were determined in undehydrated and dehydrated samples. Two drying temperatures (45 and 65 °C) and two air flow rates (3 and 5 m s?1) were evaluated. The rheology of samples under the best drying conditions was also studied, since it provides important information regarding processing (mixing, flow processing) as well as the sensory attributes (texture) of rehydrated samples. RESULTS: Non‐Newtonian shear‐thinning behaviour was observed for samples dried at 45 °C, while samples dried at 65 °C showed shear‐thickening behaviour, possibly caused by thermal chain scission of high‐molecular‐weight components. CONCLUSION: The best conditions for bioactive compound preservation were a drying temperature of 45 °C and an air flow rate of 3 m s?1, resulting in 40.97 g phenols, 23.41 g flavonoids, 0.543 g β‐carotene and 0.2815 g ascorbic acid kg?1 sample as shown in table 3. Copyright © 2011 Society of Chemical Industry 相似文献
80.
In this work the thermoeconomic features of two different combined cycles using air “open loop” and steam “closed loop” cooled gas turbines are presented and compared in depth. In order to properly estimate both thermodynamic and thermoeconomic performance of the different combined cycles an analytical model of the blade cooling system has been developed in details and outlined in the paper. Internal Thermoeconomic functional analysis is not performed here, as only economic results are shown and discussed. The blade cooling detailed model, originally developed by TPG researchers, has been integrated into the web based modular code WTEMP, already validated for GT based cycles, developed in the last ten years by TPG. It is shown that the closed loop blade cooling configuration has the greatest potential in terms of thermodynamic efficiency and economic competitivity in the mid-term. 相似文献