全文获取类型
收费全文 | 1732篇 |
免费 | 73篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 21篇 |
综合类 | 3篇 |
化学工业 | 334篇 |
金属工艺 | 68篇 |
机械仪表 | 30篇 |
建筑科学 | 25篇 |
矿业工程 | 4篇 |
能源动力 | 39篇 |
轻工业 | 49篇 |
水利工程 | 5篇 |
石油天然气 | 5篇 |
无线电 | 269篇 |
一般工业技术 | 481篇 |
冶金工业 | 224篇 |
原子能技术 | 14篇 |
自动化技术 | 243篇 |
出版年
2023年 | 20篇 |
2022年 | 23篇 |
2021年 | 42篇 |
2020年 | 38篇 |
2019年 | 42篇 |
2018年 | 51篇 |
2017年 | 57篇 |
2016年 | 58篇 |
2015年 | 39篇 |
2014年 | 55篇 |
2013年 | 97篇 |
2012年 | 61篇 |
2011年 | 72篇 |
2010年 | 64篇 |
2009年 | 71篇 |
2008年 | 61篇 |
2007年 | 63篇 |
2006年 | 45篇 |
2005年 | 32篇 |
2004年 | 43篇 |
2003年 | 50篇 |
2002年 | 45篇 |
2001年 | 29篇 |
2000年 | 30篇 |
1999年 | 32篇 |
1998年 | 55篇 |
1997年 | 33篇 |
1996年 | 44篇 |
1995年 | 32篇 |
1994年 | 41篇 |
1993年 | 30篇 |
1992年 | 26篇 |
1991年 | 21篇 |
1990年 | 23篇 |
1989年 | 15篇 |
1988年 | 22篇 |
1987年 | 22篇 |
1986年 | 22篇 |
1985年 | 26篇 |
1984年 | 22篇 |
1983年 | 17篇 |
1982年 | 11篇 |
1981年 | 14篇 |
1980年 | 13篇 |
1979年 | 12篇 |
1978年 | 17篇 |
1977年 | 20篇 |
1976年 | 10篇 |
1973年 | 7篇 |
1968年 | 6篇 |
排序方式: 共有1814条查询结果,搜索用时 265 毫秒
81.
Sintering of 434£ ferritic stainless steel powder compacts containing 0-8 volume %cx-AI20 a (1 J.1m size) and 0-4 weight % phosphorus in the form of either FesP or Fe2P was carried out in the temperature range 1150°C-1300°C, and the resultant densification parameters, ultimate compressive strengths and hardnesses were measured. The results reveal that temperatures of 1150°C and 1200°C produced liquid-phase sintering when phosphorus was added in the form of FeaP. With Fe2P additions, a higher sintering temperature of 1300°C densified the composites, and an increase in the phosphorus content to 3% uniformly enhanced the sintered properties: The presence of Al20 a particles at an optimum level only improved the properties of the liquid-phase sintered composites. 相似文献
82.
Balraj Singh Daniel Abriola Coral Baglin Vivian Demetriou Timothy Johnson Elizabeth McCutchan Gopal Mukherjee Sukhjeet Singh Alejandro Sonzogni Jagdish Tuli 《Nuclear Data Sheets》2013,114(6-7):661-749
The evaluated spectroscopic data are presented for 11 known nuclides of mass 211 (Hg, Tl, Pb, Bi, Po, At, Rn, Fr, Ra, Ac, Th). The 211Pa nuclide is included here but its identification remains uncertain. For 211Hg, 211Tl, 211Ac and 211Th nuclei, only the ground–state information is available. Their decay characteristics are mostly unknown. 211Fr is suggested to decay partially through ε decay mode, but its decay scheme remains poorly known. While high–spin excitations, including several isomers, are well studied in 211Pb, 211Bi, 211Po, 211At, 211Rn and 211Fr, the particle–transfer data are available for only 211Po and 211Bi.This evaluation was carried out as part of joint IAEA–ICTP workshop for Nuclear Structure and Decay Data, organized and hosted by the IAEA, Vienna and ICTP, Trieste, August 6–17, 2012. This work supersedes previous A=211 evaluation (2004Br45) published by E. Browne which covered literature before January 2003. 相似文献
83.
Swarnakamal Mukherjee Soumyajit Sarkar T. Saha-Dasgupta 《Journal of Materials Science》2012,47(21):7660-7664
Employing first-principles density functional theory based calculations we investigated the change in electronic structure of CaCu3B4O12 compounds as one moves from 3d (Co) to 4d (Rh) to 5d (Ir) element at B site. Our study sheds light on valences of Cu and B ions as one moves from 3d to 4d to 5d based compounds. The valence of Cu in Co and Rh compound turn out to be that of less known 3+ state, while that in Ir compound turn out to be commonly known 2+ state. Our first-principles study provide microscopic understanding of these different valences of Cu, in terms of changes in the mixing of Cu x 2 − y 2 and B-a 1g states, driven by changes in the crystal field and spin splitting. The stronger crystal field splitting for 4d and 5d elements compared to 3d at B site drive the low-spin state at Rh and Ir site as opposed to intermediate spin in case of Co. 相似文献
84.
Jonathan Sampath Franklyne Swati Iyer Andrew Ebenazer Amitava Mukherjee Natarajan Chandrasekaran 《International Journal of Food Science & Technology》2019,54(9):2802-2810
Many human acid tolerant bacterial and fungal pathogens can be transmitted through the consumption of the contaminated fruit juices. We aim to formulate essential oil nanoemulsions (basil, black seed, turmeric, clove & cinnamon), determine their ability to clear contamination by food borne bacterial pathogens from fruit juices. The antibacterial activity of the optimised formulations was tested in the fruit juices against bacterial pathogens causing gastrointestinal tract infections. The minimum bactericidal concentration (MBC) of clove emulsions ranged from 15.6 to 25 μL mL−1. Cinnamon oil emulsion had an MBC ranging between 15 and 31 μL mL−1. At MBC, cinnamon oil emulsions caused a 6log10 decrease in viable counts by 8 h and maintained the sterility of fruit juices for 7 days at ambient temperature. Thus, clove and cinnamon microemulsions can be used as juice additives to control food borne bacterial pathogens and maintain the bacterial sterility of fruit juices. 相似文献
85.
Pitambar Randive Amaresh Dalal Partha P. Mukherjee 《Microfluidics and nanofluidics》2014,17(4):657-674
The importance of fundamental understanding of droplet dynamics and the concomitant implications of wall wettability are critical in the emergent science and technology areas including digital microfluidics and clean energy conversion. In this work, mesoscopic illustration, based on the two-phase lattice Boltzmann model, of droplet dynamics in a microchannel is presented in order to unveil the role of superhydrophobicity and mixed wettability. The impact of critical physicochemical determinants, including capillary number and droplet size, is explored in the context of droplet–wettability interactions. Temporal evolution of wetted length and wetted area for a combination of wettability scenarios is furnished in detail in order to elucidate the droplet displacement dynamics. Capillary number plays an important role with disparate droplet behavioral patterns stemming from superhydrophobic and mixed-wet wall characteristics. 相似文献
86.
87.
R. Nagarajan Anupam Mukherjee A. Roy M. V. Khire 《International journal of remote sensing》2013,34(4):573-585
Spatial and temporal multi-layered information is required to assess landslide hazard susceptibility. The manual method of data integration for targeting potential zones susceptible to landslide hazard is time consuming. The present study highlights the utility of temporal remotely-sensed data and knowledgebased Geographical Information Systems for collection, integration and analysis of spatially-oriented data, as well as in finding out the inherent relation between separate entities in parts of West ghat in India. 相似文献
88.
A qualitative and quantitative research has been performed on the physico-chemical parameters of the neighboring coastal waters of the rivers Matla and Saptamukhi in the Sunderban district, West Bengal. The distribution pattern of eight physico-chemical parameters, namely pH, salinity, dissolved oxygen, suspended solids, nitrogen and phosphorus concentrations (inorganic and total) has been graphed and compared for the two rivers over a time period of ten years (??90s decade). A statistical analysis has been carried out and the correlation data between these parameters has been rationalized based on both natural and man-made activities during that time. This has pointed to various causes behind coastal pollution of river waters. The changes in water quality have been related to flood impacts, storm surge, eutrophication, domestic sewage, agricultural and industrial wastes. In order to avoid coastal degradation and maintain environmental balance, it is very important to understand the impact of these parameters on coastal zones. 相似文献
89.
Jane H. Fujiyama-Novak Amrita Mukherjee Ganesh Rahul Bhimanapati Chethan Kumar Gaddam Randy L. Vander Wal Benjamin Ward 《Combustion and Flame》2012,159(3):1160-1164
In this study the main objective was to develop and demonstrate a glow discharge microplasma coupled to a miniature spectrometer for detection of fire signatures from pyrolyzing and burning spacecraft materials. Our experimental results demonstrate that combustion-produced carbonaceous aerosols can serve to identify the burning materials. Demonstrating versatility for chemistry analysis, the plasma detector could differentiate carbonaceous aerosols with different C/H ratios and distinguish inorganic samples such as salts and metal oxides from carbonaceous aerosols. In addition, in situ analysis of aerosol samples validated the microplasma’s analytical utility by linearity of its optical emission intensity with aerosol elemental composition. 相似文献
90.
Moumita Mukherjee Biswanath Mukherjee Youngill Choi Kyoseung Sim Junghwan Do Seungmoon Pyo 《Synthetic Metals》2010,160(5-6):504-509
We report a copper hexadecafluorophthalocyanine (F16CuPc) based n-type organic field-effect transistor (OFET) with polymeric gate dielectrics with different physical/electrical properties. The gate dielectrics are four types of cross-linked poly(4-vinylphenol) and newly prepared poly(4-phenoxy methyl styrene) and those are characterized based on surface tension, leakage current and capacitance. The performance of F16CuPc OFETs with those gate dielectrics was compared. We found that the composition of the gate dielectrics and the interfacial interaction of F16CuPc with the gate dielectric play a decisive role in the performance of OFETs. The effect of physical/electrical properties, composition and processing condition of the gate dielectrics on the device performance was investigated. 相似文献