全文获取类型
收费全文 | 600篇 |
免费 | 33篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 153篇 |
金属工艺 | 11篇 |
机械仪表 | 12篇 |
建筑科学 | 7篇 |
能源动力 | 45篇 |
轻工业 | 41篇 |
水利工程 | 8篇 |
无线电 | 64篇 |
一般工业技术 | 142篇 |
冶金工业 | 16篇 |
原子能技术 | 6篇 |
自动化技术 | 125篇 |
出版年
2024年 | 4篇 |
2023年 | 8篇 |
2022年 | 15篇 |
2021年 | 33篇 |
2020年 | 31篇 |
2019年 | 29篇 |
2018年 | 31篇 |
2017年 | 32篇 |
2016年 | 20篇 |
2015年 | 19篇 |
2014年 | 34篇 |
2013年 | 54篇 |
2012年 | 46篇 |
2011年 | 36篇 |
2010年 | 38篇 |
2009年 | 31篇 |
2008年 | 35篇 |
2007年 | 35篇 |
2006年 | 19篇 |
2005年 | 14篇 |
2004年 | 13篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1975年 | 1篇 |
排序方式: 共有634条查询结果,搜索用时 0 毫秒
91.
92.
Streptococcus thermophilus strains of plant origin as dairy starters: Isolation and characterisation
Thiyagamoorthy Umamaheswari Kaliyaperumal Anbukkarasi Prashant Singh Sudhir K Tomar Rameshwar Singh 《International Journal of Dairy Technology》2014,67(1):117-122
Streptococcus thermophilus strains have been isolated mainly from dairy environments. To prospect for new strains of S. thermophilus, isolation was made from different plant sources. In this study, 74 plant isolates were characterised as S. thermophilus by a polyphasic approach and by 16S rRNA sequencing. The isolates were further evaluated for their physiological and biochemical properties. Plant isolates exhibited good acid production and varying proteolytic activity. All the isolates showed acetaldehyde and capsular exopolysaccharide (EPS) production and few revealed diacetyl production. In contrast to industrial strains, six isolates were able to ferment galactose and 25 were found to have no urease activity. Both the plant isolates and reference dairy cultures were found to possess similar physiological and biochemical properties and can be considered for developing new starters. 相似文献
93.
Localized surface plasmon resonances (LSPRs) typically arise in nanostructures of noble metals resulting in enhanced and geometrically tunable absorption and scattering resonances. LSPRs, however, are not limited to nanostructures of metals and can also be achieved in semiconductor nanocrystals with appreciable free carrier concentrations. Here, we describe well-defined LSPRs arising from p-type carriers in vacancy-doped semiconductor quantum dots (QDs). Achievement of LSPRs by free carrier doping of a semiconductor nanocrystal would allow active on-chip control of LSPR responses. Plasmonic sensing and manipulation of solid-state processes in single nanocrystals constitutes another interesting possibility. We also demonstrate that doped semiconductor QDs allow realization of LSPRs and quantum-confined excitons within the same nanostructure, opening up the possibility of strong coupling of photonic and electronic modes, with implications for light harvesting, nonlinear optics, and quantum information processing. 相似文献
94.
Maityt D Pradhan P Chandrasekharan P Kale SN Shuter B Bahadur D Feng SS Xue JM Ding J 《Journal of nanoscience and nanotechnology》2011,11(3):2730-2734
In this paper, we report single step synthesis of hydrophilic superparamagnetic magnetite nanoparticles by thermolysis of Fe(acac)3 and their characterization of the properties relevant to biomedical applications like hyperthermia and magnetic resonance imaging (MRI). Size and morphology of the particles were determined by Transmission electron microscopy (TEM) while phase purity and structure of the particles were identified by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). Magnetic properties were evaluated using vibrating sample magnetometer (VSM) and superconducting quantum interference device (SQUID) measurements. The as prepared nanoparticles were found to be superparamagnetic with the blocking temperature of 136 K and were easily suspendable in water. Cytotoxicity studies on human cervical (SiHa), mouse melanoma (B16F10) and mouse primary fibroblast cells demonstrated that up to a dose of 0.1 mg/ml, the magnetite nanoparticles were nontoxic to the cells. To evaluate the feasibility of their uses in hyperthermia and MRI applications, specific absorption rate (SAR) and spin-spin relaxation time (T2) were measured respectively. SAR has been calculated to be above 80 Watt/g for samples with the iron concentration of 5-20 mg/ml at 10 kA/m AC magnetic field and 425 kHz frequency. r2 relaxivity value was measured as 358.4 mM(-1)S(-1) which is almost double as compared to that of the Resovist, a commercially available MRI contrast agent. Thus the as-prepared magnetite nanoparticles may be used for hyperthermia and MRI applications due to their promising SAR and r2 values. 相似文献
95.
Moni Kanchan Datta Jeffrey Maranchi Sung Jae Chung Rigved Epur Karan Kadakia Prashanth Jampani Prashant N. Kumta 《Electrochimica acta》2011,(13):4717
The buffering effect of carbon on the structural stability of amorphous silicon films, used as an anode for lithium ion rechargeable batteries, has been studied during long term discharge/charge cycles. To this extent, the electrochemical performance of a prototype material consisting of amorphous Si thin film (∼250 nm) deposited by radio frequency magnetron sputtering on amorphous carbon (∼50 nm) thin films, denoted as a-C/Si, has been investigated. In comparison to pure amorphous Si thin film (a-Si) which shows a rapid fade in capacity after 30 cycles, the a-C/Si exhibits excellent capacity retention displaying ∼0.03% fade in capacity up to 50 cycles and ∼0.2% after 50 cycles when cycled at a rate of 100 μA/cm2 (∼C/2) suggesting that the presence of thin amorphous C layer deposited between the Cu substrate and a-Si acts as a buffer layer facilitating the release of the volume induced stresses exhibited by pure a-Si during the charge/discharge cycles. This structural integrity combined with microstructural stability of the a-C/Si thin film during the alloying/dealloying process with lithium has been confirmed by scanning electron microscopy (SEM) analysis. The buffering capacity of the thin amorphous carbon layer lends credence to its use as the likely compliant matrix to curtail the volume expansion related cracking of silicon validating its choice as the matrix for bulk and thin film battery systems. 相似文献
96.
G. Selvarani S.K. Prashant A.K. Sahu P. Sridhar S. Pitchumani A.K. Shukla 《Journal of power sources》2008
A direct borohydride-hydrogen peroxide fuel cell employing carbon-supported Prussian Blue (PB) as mediated electron-transfer cathode catalyst is reported. While operating at 30 °C, the direct borohydride-hydrogen peroxide fuel cell employing carbon-supported PB cathode catalyst shows superior performance with the maximum output power density of 68 mW cm−2 at an operating voltage of 1.1 V compared to direct borohydride-hydrogen peroxide fuel cell employing the conventional gold-based cathode with the maximum output power density of 47 mW cm−2 at an operating voltage of 0.7 V. X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray Analysis (EDAX) suggest that anchoring of Cetyl-Trimethyl Ammonium Bromide (CTAB) as a surfactant moiety on carbon-supported PB affects the catalyst morphology. Polarization studies on direct borohydride-hydrogen peroxide fuel cell with carbon-supported CTAB-anchored PB cathode exhibit better performance with the maximum output power density of 50 mW cm−2 at an operating voltage of 1 V than the direct borohydride-hydrogen peroxide fuel cell with carbon-supported Prussian Blue without CTAB with the maximum output power density of 29 mW cm−2 at an operating voltage of 1 V. 相似文献
97.
Effect of working gap and circumferential speed on the performance of magnetic abrasive finishing process 总被引:2,自引:0,他引:2
Magnetic abrasive finishing (MAF) is one of the advanced finishing processes in which workpiece is kept between two magnets, and cutting force is controlled by working gap and magnetic field between the two magnets. MAF setup is designed for finishing cylindrical workpieces and it is mounted on lathe machine. The loosely bounded powder is prepared for experimentation by homogeneous mixing of magnetic powder (Fe powder of 300 mesh size (51.4 μm)), abrasive powder (Al2O3 of 600 mesh size (25.7 μm), and lubricant called servospin-12 oil. To investigate the effects of working gap and circumferential speed on material removal, change in surface finish and percent improvement in surface finish, a series of experiments have been conducted using in-house fabricated setup. Based upon the results, in general, material removal decreases by increasing working gap or decreasing circumferential speed of the workpiece. Change in surface finish increases by increasing circumferential speed of the workpiece. 相似文献
98.
Application of Petri Nets and a Genetic Algorithm to Multi-Mode Multi-Resource Constrained Project Scheduling 总被引:2,自引:0,他引:2
J. Prashant Reddy S. Kumanan O.V. Krishnaiah Chetty 《The International Journal of Advanced Manufacturing Technology》2001,17(4):305-314
Multi-mode and multi-resource constrained scheduling of a project is a complex task. This paper addresses the use of a Petri
net as a modelling and scheduling tool in this context. The benefits of Petri nets in project scheduling are discussed. We
propose extensions to Petri nets to suit scheduling of activities in a decision CPM. We also propose the use of a P-matrix
for token movements in Petri nets. A genetic algorithm is used to find a better solution. Petri-net-aided software including
genetic-algorithm-based search and heuristics is described to deal with a multi-mode, multi-constrained scheduling problem
with pre-emption of activities. 相似文献
99.
Minh Tam Hoang Amandeep Singh Pannu Yang Yang Sepideh Madani Paul Shaw Prashant Sonar Tuquabo Tesfamichael Hongxia Wang 《纳微快报(英文)》2022,(4):277-288
The remarkable evolution of metal halide perovskites in the past dec-ade makes them promise for next-generation optoelectronic material.In particular,nanocrysta... 相似文献
100.
The effect of rubber hardness on the properties of fiber‐reinforced plastic (FRP) composites is investigated in order to know the optimum composition of rubber mold used in rubber pressure molding (RPM) technique. A matching die set was used in RPM method, where the die was made of hard metal like steel and the punch from the flexible rubber like material, natural rubber. The use of flexible rubber punch generates and applies hydrostatic pressure on the surface of FRP composites. The hardness of rubber mold was controlled by incorporating carbon black as a filler material in the matrix of natural rubber and varied from 0 to 75 phr (per hundred rubber) in steps of 15 phr. Burn test, tension test, interlaminar shear test and interlaminar fracture toughness tests were conducted on the FRP composites to measure the void content, presence of delamination, tensile strength, inter laminar shear strength and inter laminar fracture toughness. The results are compared with the FRP composites made by conventional technique to evaluate the performance of RPM technique. It is observed that the laminates produced by RPM technique with different filler content in natural rubber mold show significant improvement in mechanical properties except interlaminar shear strength. POLYM. COMPOS., 28:618–630, 2007. © 2007 Society of Plastics Engineers 相似文献