全文获取类型
收费全文 | 321篇 |
免费 | 16篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 66篇 |
金属工艺 | 5篇 |
机械仪表 | 4篇 |
建筑科学 | 4篇 |
能源动力 | 11篇 |
轻工业 | 15篇 |
水利工程 | 4篇 |
无线电 | 54篇 |
一般工业技术 | 91篇 |
冶金工业 | 27篇 |
原子能技术 | 5篇 |
自动化技术 | 49篇 |
出版年
2023年 | 3篇 |
2022年 | 10篇 |
2021年 | 12篇 |
2020年 | 14篇 |
2019年 | 12篇 |
2018年 | 11篇 |
2017年 | 14篇 |
2016年 | 18篇 |
2015年 | 13篇 |
2014年 | 18篇 |
2013年 | 19篇 |
2012年 | 12篇 |
2011年 | 12篇 |
2010年 | 10篇 |
2009年 | 10篇 |
2008年 | 7篇 |
2007年 | 11篇 |
2006年 | 11篇 |
2005年 | 9篇 |
2004年 | 9篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 4篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有339条查询结果,搜索用时 15 毫秒
21.
Kumar Rajneesh Goel Varun Kumar Anoop Khurana Sourabh Singh Paramvir Bopche Santosh B. 《Journal of Mechanical Science and Technology》2018,32(1):399-404
Journal of Mechanical Science and Technology - The Computational fluid dynamics (CFD) based analysis is carried out to investigate the thermal and hydraulic performance of circular rib roughened... 相似文献
22.
Sourabh Dongaonkar Muhammad A. Alam 《Progress in Photovoltaics: Research and Applications》2015,23(2):170-181
Partial shading in photovoltaic modules is an important reliability and performance concern for all photovoltaic technologies. In this paper, we show how cell geometry can be used as a design variable for improved shade tolerance and performance in monolithic thin film photovoltaic modules (TFPV). We use circuit simulations to illustrate the geometrical aspects of partial shading in typical monolithic TFPV modules with rectangular cells, and formulate rules for shade tolerant design. We show that the problem of partial shading can be overcome by modifying the cell shape and orientation, while preserving the module shape and output characteristics. We discuss two geometrical designs with cells arranged in radial and spiral patterns, which (i) prevent the reverse breakdown of partially shaded cells, (ii) improve the overall power output under partial shading, and (iii) in case of spiral design, may additionally improve the module efficiency by reducing sheet resistance losses. We compare these designs quantitatively using realistic parameters and discuss the practical aspects for their implementation. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
23.
Ansuman Barman Nilesh Kumar Shrivastava Bhanu Bhusan Khatua Bidhan Chandra Ray 《Polymer Composites》2015,36(12):2157-2166
Here we report the preparation and characterization of a green composite based on high‐density polyethylene and Kaans grass (Saccharum spontaneum). The composites were prepared by conventional melt‐mixing method, using maximum loading of Kaans grass in powder form (KG‐filler) to achieve acceptable range of required properties. Maleic anhydride grafted polyethylene was used as compatibilizer to achieve effective interaction for improved surface adhesion which was confirmed by FT‐IR spectroscopy. Morphological studies revealed good interaction between the base polymer matrices and the KG‐fillers that improved the mechanical and thermal properties of the composites up to certain (10 phr) KG‐filler loading. Study on water absorption property revealed moderate increase in weight at higher KG‐filler loadings. Thermogravimetric analysis (TGA) and melt flow index (MFI) studies indicated retention of thermal stability and flow property of the HDPE/KG‐filler composite at lower filler loadings. POLYM. COMPOS., 36:2157–2166, 2015. © 2014 Society of Plastics Engineers 相似文献
24.
Moitree Taran Dipankar Deb Sourabh Deb 《Energy Sources, Part A: Recovery, Utilization, and Environmental Effects》2016,38(17):2545-2552
The present study was undertaken to identify the fuelwood plant species and their utilization pattern by the Halam community of Tripura. The main objective of this study was to assess the species preference as fuelwood, the total value index, and the fuelwood value index (FVI) of 22 species. The majority of the households use the plant resources for domestic purpose. Although the community’s mostly preferred fuelwood species were Tectona grandis L.f, Shorea robusta C. F. Gaertn, and Gmelina arborea Roxb, a total of 22 species were reported from the study site. Trewia nudiflora L., Albizia procera Benth., Dysoxylum procerum Hierm., and Cassia siamea Lam. were also reported as fuelwood species with good wood quality (FVI). Thus awareness on the use of these species as fuelwood can be increased in the community to reduce stress on the preferred species and the surrounding forest. 相似文献
25.
Stimulus responsive hydrogels are being considered as one of the most crucial biomaterials of current generation. A new technique has been established for developing hydrogels based on Acrylic acid (AAc) and N-[3-(Dimethylamino)propyl]-methacrylamide (DMAPMA), and relevant mechanism has been delineated. Aqueous redox copolymerization of different molar ratios of AAc and DMAPMA at 41 ± 1 °C, leading to the formation of interlocked nanogels of ∼300 nm diameter, which acted as the building blocks of a series of superabsorbent hydrogels having robust, honey-comb type three-dimensional architecture. Monomer composition, monomer feed ratio and water content in feed has been found to be important factors in the development of the stable poly(AAc-co-DMAPMA) hydrogel membranes (PADMAs) without any active crosslinking agent. At the cues of pH change from 7.0 to 3.5, pulsatile swelling-deswelling behavior varied, ranging from ∼5900% to ∼60% (mass) respectively, underlining smart hydrogel characteristics needed for specific biomedical applications. Elastic modulus of the gels, equilibrated at pH 7.0, is recorded to be >15 kPa under uniaxial compression. Underlying mechanism of the formation of such robust three-dimensional structures in poly(AAc-co-DMAPMA) hydrogel membranes, and the origin of hierarchical ‘nano-to-macro’ scale morphological features has been proposed. 相似文献
26.
An approach that links a Monte-Carlo simulation based reliability program with the water treatment process behavior and performance model is presented for uncertainty analysis of the conventional water treatment plant (WTP) design. The expected mass concentration of suspended solids (SS) in the effluent water is employed as a measurement of system reliability. The approach for uncertainty analysis of a WTP is illustrated with a hypothetical case study. The parameters contributing significantly to the variability of SS concentration in the effluent water are identified. From an operational viewpoint, the variability in effluent water quality resulting from uncertainty in the system parameters is investigated. Also, improvement in the reliability of WTP using modified design parameters is investigated along with its cost implications. From the results, a method to calculate a set of safety factors corresponding to various performance reliability levels is proposed. 相似文献
27.
28.
Shrivastava A. Ramanadhan P. Shah A. Jamadagni H. 《Communications, IEEE Transactions on》1978,26(3):368-373
An Autonomous Line Scanning Unit (ALSU) for completely autonomous detection of call originations in the SPC Telephone Switching System is described. Through its own memories, ALSU maintains an up-to-date record of subscribers' statuses, detects call originations, performs 'hit timing check' and informs the Switching System of the identity of calling subscribers. The ALSU needs minimum interaction with the Central Processor, resulting in increased call handling capacity. 相似文献
29.
Anshul Shrivastava Michael H. Azarian Michael Pecht 《Journal of Failure Analysis and Prevention》2016,16(6):1059-1066
Aluminum electrolytic capacitors with polymer electrolytes were developed to obtain lower equivalent series resistance (ESR) than that is achievable with liquid electrolytes. Replacement of the liquid electrolyte with a solid conductive polymer also overcomes the propensity of the liquid to evaporate over time, which leads to a reduction in capacitance and an increase in ESR values. However, capacitor manufacturers acknowledge that humidity can degrade the polymer, thereby having an adverse effect on the reliability of polymer aluminum (PA) capacitors. In the current study, surface mount and thru-hole PA capacitors from two different manufacturers were subjected to highly accelerated stress testing (110 °C, 85% RH) and elevated temperature–humidity (85 °C, 85% RH) conditions for rapid assessment. The polymer electrolyte in the capacitors was poly(3,4-ethylenedioxythiophene). Failure analysis was performed to determine the observed failure modes and the underlying failure mechanisms. The dominant failure modes observed were an increase in leakage current and an increase in ESR. 相似文献
30.
Sourabh K. Saha S.K. Choudhury 《International Journal of Machine Tools and Manufacture》2009,49(3-4):297-308
Dry electric discharge machining (EDM) is an environment-friendly modification of the oil EDM process in which liquid dielectric is replaced by a gaseous medium. In the current work, parametric analysis of the process has been performed with tubular copper tool electrode and mild steel workpiece. Experiments have been conducted using air as the dielectric medium to study the effect of gap voltage, discharge current, pulse-on time, duty factor, air pressure and spindle speed on material removal rate (MRR), surface roughness (Ra) and tool wear rate (TWR). First, a set of exploratory experiments has been performed to identify the optimum tool design and to select input parameters and their levels for later stage experiments. Empirical models for MRR, Ra and TWR have then been developed by performing a designed experiment based on the central composite design of experiments. Response surface analysis has been done using the developed models. Analysis of variance (ANOVA) tests were performed to identify the significant parameters. Current, duty factor, air pressure and spindle speed were found to have significant effects on MRR and Ra. However, TWR was found to be very small and independent of the input parameters. 相似文献