全文获取类型
收费全文 | 991篇 |
免费 | 29篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 16篇 |
综合类 | 5篇 |
化学工业 | 256篇 |
金属工艺 | 16篇 |
机械仪表 | 27篇 |
建筑科学 | 14篇 |
矿业工程 | 1篇 |
能源动力 | 45篇 |
轻工业 | 55篇 |
水利工程 | 1篇 |
无线电 | 110篇 |
一般工业技术 | 243篇 |
冶金工业 | 81篇 |
原子能技术 | 6篇 |
自动化技术 | 148篇 |
出版年
2024年 | 4篇 |
2023年 | 18篇 |
2022年 | 31篇 |
2021年 | 47篇 |
2020年 | 41篇 |
2019年 | 41篇 |
2018年 | 43篇 |
2017年 | 30篇 |
2016年 | 44篇 |
2015年 | 19篇 |
2014年 | 29篇 |
2013年 | 82篇 |
2012年 | 40篇 |
2011年 | 50篇 |
2010年 | 51篇 |
2009年 | 36篇 |
2008年 | 43篇 |
2007年 | 41篇 |
2006年 | 37篇 |
2005年 | 28篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2002年 | 9篇 |
2001年 | 15篇 |
2000年 | 7篇 |
1999年 | 5篇 |
1998年 | 25篇 |
1997年 | 14篇 |
1996年 | 19篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 14篇 |
1992年 | 5篇 |
1991年 | 8篇 |
1989年 | 7篇 |
1988年 | 4篇 |
1987年 | 13篇 |
1986年 | 7篇 |
1985年 | 11篇 |
1984年 | 12篇 |
1983年 | 7篇 |
1982年 | 10篇 |
1981年 | 8篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 7篇 |
1974年 | 2篇 |
1973年 | 2篇 |
排序方式: 共有1024条查询结果,搜索用时 15 毫秒
91.
Parag A. Deshpande M. S. Hegde Giridhar Madras 《American Institute of Chemical Engineers》2010,56(5):1315-1324
The water‐gas shift (WGS) reaction was carried out in the presence of Pd and Pt substituted nanocrystalline ceria catalysts synthesized by solution combustion technique. The catalysts were characterized by powder XRD and XPS. The noble metals were found to be present in ionic form substituted for the cerium atoms. The catalysts showed high activity for the WGS reaction with high conversions below 250°C. The products of reaction were only carbon dioxide and hydrogen, and no hydrocarbons were observed even in trace quantities. The reactions were carried out with different amounts of noble metal ion substitution and 2% Pt substituted ceria was found to be the best catalyst. The various possible mechanisms for the reaction were proposed and tested for their consistency with experimental data. The dual site mechanism best described the kinetics of the reaction and the corresponding rate parameters were obtained. © 2009 American Institute of Chemical Engineers AIChE J, 2010 相似文献
92.
Vipin Kumar Soniya Juneja Sachin K. Sharma V. Singh T. P. Sharma 《Journal of Coatings Technology and Research》2010,7(3):399-402
In the present investigation, the polycrystalline films of Cd
X
Zn1–X
S were prepared using a sintering technique. We coated slurry consisting of CdS, ZnS in the desired proportion—CdCl2 (as adhesive) and ethylene glycol (as binder)—onto the glass substrates. The films were sintered at a range of temperatures
in air atmosphere for the optimization of sintering temperatures using reflection spectroscopy. It was noticed that below
500°C, CdS-dominated films were obtained, and above 500°C, ZnS-dominated films were obtained. The films of desired composition
giving appropriate results are obtained at 500°C. The reason is easily understood through reflection spectroscopic studies.
Thus, we found 500°C to be the optimum sintering temperature and 10 min was the proper sintering time. 相似文献
93.
Calculation of Channel Capacity Considering the Effect of Different Seasons for Higher Altitude Platform System 总被引:1,自引:1,他引:0
This paper presents effect of the weather impairments on a high altitude platform (HAP) broadband wireless communication system.
It is shown that attenuation due to oxygen, water vapor, fog, cloud, and rain has significant effect on a radio link which
is operating in a millimeter frequency range. Channel capacity is calculated for different seasons using Shannon’s channel
capacity theorem. The location of HAP is taken to be Delhi (India). Further, it is considered that a user and the HAP platform
are stationary. 相似文献
94.
Accurately predicting the heat transfer characteristics of coolants used in thermal management of energy systems like heat exchangers, power electronics, and heating, ventilation, and air conditioning is indispensable in maintaining its operating conditions within safety limits. Apart from safety, factors such as power consumption and operating cost are the most important constraints to be considered in designing an energy-efficient and cost-effective cooling solution. In this study, the experimental data available from previous research on the use of functionalized graphene-based nanofluids in compact heat exchangers such as the automotive radiator is used to optimize the heat transfer performance parameters like Nusselt number of the nanofluid, the friction factor, and effectiveness of the heat exchanger. A supervised machine learning technique like the artificial neural network is used to obtain the objective functions of the response variables in terms of input features such as Reynolds number, Prandtl number, the volume concentration of nanoparticles in the base fluid, number of transfer units, heat capacity, the density of nanofluid, pressure drop and velocity. On the current dataset, it is found that by using the Bayesian regularization training algorithm and tangent sigmoidal activation function in the neural network, the best accuracies in the prediction can be achieved. Well-known nature-inspired optimization algorithms like genetic algorithms and simulated annealing are used in optimizing the above-mentioned response variables. Both algorithms converged to the same values of the objective functions. The optimum values of Nusselt number, effectiveness, and friction factor are 105.65, 0.506, and 0.0038, respectively, for the given composition of the nanofluid and radiator configuration. 相似文献
95.
An analysis is built up for the exploration of radiative heat transport on the magnetohydrodynamic flow of rotating fluid over a vertical sheet. The inclusion of thermal radiation in conjunction with the reacting species enhances the energy as well as the solutal profiles respectively. In an advance, external heat source and applied magnetic field effects are considered for further improvement. As the magnetic Reynolds number is low, the influence of the induced magnetic field is neglected. The transformation of governing nonlinear partial differential equations into coupled nonlinear ordinary differential equations is attained with a proper supposition of similarity variables. Moreover, the solution of these transformed equations is scheduled using the “Runge–Kutta fourth-order” method numerically in association with the “shooting technique.” The simulation or various illustrating parameters affecting the flow phenomena are obtained and displayed through graphs and for numerical validation with earlier published work shows the convergence process of the methodology applied. The main findings of the study are; the Dufour number is favorable to enhance the fluid temperature throughout the domain and the destructive chemical reaction also encourages the solutal profile significantly. 相似文献
96.
Anindita Bhadra Aniruddha Mitra Sujata A. Deshpande Kannepalli Chandrasekhar Dattatraya G. Naik Abraham Hefetz Raghavendra Gadagkar 《Journal of chemical ecology》2010,36(4):424-431
Queens and workers are not morphologically differentiated in the primitively eusocial wasp, Ropalidia marginata. Upon removal of the queen, one of the workers becomes extremely aggressive, but immediately drops her aggression if the
queen is returned. If the queen is not returned, this hyper-aggressive individual, the potential queen (PQ), will develop
her ovaries, lose her hyper-aggression, and become the next colony queen. Because of the non-aggressive nature of the queen,
and because the PQ loses her aggression by the time she starts laying eggs, we hypothesized that regulation of worker reproduction
in R. marginata is mediated by pheromones rather than by physical aggression. Based on the immediate loss of aggression by the PQ upon return
of the queen, we developed a bioassay to test whether the queen’s Dufour’s gland is, at least, one of the sources of the queen
pheromone. Macerates of the queen’s Dufour’s gland, but not that of the worker’s Dufour’s gland, mimic the queen in making
the PQ decrease her aggression. We also correctly distinguished queens and workers of R. marginata nests by a discriminant function analysis based on the chemical composition of their respective Dufour’s glands. 相似文献
97.
98.
Ilona BOBEK Dehua GONG Massimo DE CAL Dinna CRUZ Chang Y. CHIONH Mikko HAAPIO Sachin S. SONI Federico NALESSO Paolo LENTINI Francesco GARZOTTO Valentina CORRADI Claudio RONCO 《Hemodialysis international. International Symposium on Home Hemodialysis》2010,14(3):302-307
Neutrophil gelatinase‐associated lipocalin (NGAL) protein is an early biomarker for acute kidney injury (AKI). It is unknown if extracorporeal therapies (EC) have an effect on circulating NGAL levels. This study was designed to describe the kinetics of NGAL molecule in different EC techniques and to evaluate NGAL clearance in different operational conditions. A mock hemofiltration (HF) and hemoperfusion (HP) setup was used. NGAL was added to the blood reservoir and then measured at 30‐minute intervals from arterial, venous, and ultrafiltrate (UF) lines. Removal kinetics and NGAL sieving coefficient were calculated. In our experiments, baseline NGAL concentration averaged 452 μg/L. There was a consistent downward trend throughout the experiment. NGAL concentration in the UF was between 80 and 90 μg/L, though it showed a slight increase in the second hour. The sieving coefficient of NGAL ranged from 0.2 to 0.4 during HF and it appeared to increase with time, suggesting an initial effect of membrane adsorption. HP proved clearly that there was adsorption of NGAL by the membrane and the point of saturation occured at approximately 60 minutes from the start of circulation. Our evaluation demonstrates that NGAL can be adsorbed and ultrafiltrated with polysulfone membranes. This should be taken into consideration when using NGAL as an AKI biomarker in patients undergoing EC circulation. 相似文献
99.
Anuj Deshpande Sibendu Samanta Sutharsan Govindarajan Ritwik Kumar Layek 《IET systems biology》2020,14(6):343
Dynamic biological systems can be modelled to an equivalent modular structure using Boolean networks (BNs) due to their simple construction and relative ease of integration. The chemotaxis network of the bacterium Escherichia coli (E. coli ) is one of the most investigated biological systems. In this study, the authors developed a multi‐bit Boolean approach to model the drifting behaviour of the E. coli chemotaxis system. Their approach, which is slightly different than the conventional BNs, is designed to provide finer resolution to mimic high‐level functional behaviour. Using this approach, they simulated the transient and steady‐state responses of the chemoreceptor sensory module. Furthermore, they estimated the drift velocity under conditions of the exponential nutrient gradient. Their predictions on chemotactic drifting are in good agreement with the experimental measurements under similar input conditions. Taken together, by simulating chemotactic drifting, they propose that multi‐bit Boolean methodology can be used for modelling complex biological networks. Application of the method towards designing bio‐inspired systems such as nano‐bots is discussed.Inspec keywords: cell motility, microorganisms, Boolean functionsOther keywords: multibit Boolean approach, conventional BNs, high‐level functional behaviour, steady‐state responses, chemoreceptor sensory module, drift velocity, chemotactic drifting, multibit Boolean methodology, complex biological networks, bio‐inspired systems, multibit Boolean model, chemotactic drift, dynamic biological systems, equivalent modular structure, Boolean networks, simple construction, chemotaxis network, bacterium Escherichia coli, biological systems 相似文献
100.
R. A. Daryapurkar T. Nandy S. N. Kaul C. V. Deshpande L. Szpyrkowicz 《The International journal of environmental studies》2013,70(6):835-860
An approach has been made to evaluate the kinetic constants for a two stage anaerobic fixed film fixed bed reactor system treating tannery wastewater. The research reported herein is concerned with the bench scale performance evaluation of the reactor system treating the wastewater and application of the data to various models to evaluate the kinetic constants for substrate bio‐oxidation, biomass growth and biogas yield. 相似文献