全文获取类型
收费全文 | 1823篇 |
免费 | 66篇 |
国内免费 | 9篇 |
专业分类
电工技术 | 45篇 |
综合类 | 1篇 |
化学工业 | 318篇 |
金属工艺 | 40篇 |
机械仪表 | 43篇 |
建筑科学 | 32篇 |
矿业工程 | 4篇 |
能源动力 | 81篇 |
轻工业 | 89篇 |
水利工程 | 12篇 |
石油天然气 | 7篇 |
无线电 | 352篇 |
一般工业技术 | 368篇 |
冶金工业 | 211篇 |
原子能技术 | 11篇 |
自动化技术 | 284篇 |
出版年
2024年 | 8篇 |
2023年 | 19篇 |
2022年 | 43篇 |
2021年 | 84篇 |
2020年 | 55篇 |
2019年 | 70篇 |
2018年 | 73篇 |
2017年 | 65篇 |
2016年 | 75篇 |
2015年 | 33篇 |
2014年 | 61篇 |
2013年 | 135篇 |
2012年 | 67篇 |
2011年 | 71篇 |
2010年 | 67篇 |
2009年 | 75篇 |
2008年 | 58篇 |
2007年 | 62篇 |
2006年 | 64篇 |
2005年 | 44篇 |
2004年 | 33篇 |
2003年 | 28篇 |
2002年 | 43篇 |
2001年 | 29篇 |
2000年 | 24篇 |
1999年 | 37篇 |
1998年 | 56篇 |
1997年 | 43篇 |
1996年 | 46篇 |
1995年 | 32篇 |
1994年 | 25篇 |
1993年 | 25篇 |
1992年 | 23篇 |
1991年 | 25篇 |
1990年 | 12篇 |
1989年 | 22篇 |
1988年 | 15篇 |
1987年 | 21篇 |
1986年 | 13篇 |
1985年 | 12篇 |
1984年 | 13篇 |
1983年 | 12篇 |
1982年 | 11篇 |
1981年 | 7篇 |
1980年 | 10篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 10篇 |
1974年 | 6篇 |
1971年 | 4篇 |
排序方式: 共有1898条查询结果,搜索用时 0 毫秒
41.
Peter T.Cummings Philippe M.Fauchet Michael Goldfarb Martha W.M.Jones Maithilee Kunda Jonathan B.Perlin Nilanjan Sarkar Keivan G.Stassun Zachary E.Warren Karl E.Zelik 《工程(英文)》2021,7(2):141-143,中插10-中插13
1. Background
The use of engineering tools, design, research, and thinking to create environments and capabilities whereby individuals who are currently under-e... 相似文献
42.
In multicriteria decision-making (MCDM), the existing aggregation operators are mostly based on algebraic t-conorm and t-norm. But, Archimedean t-conorms and t-norms are the generalized forms of t-conorms and t-norms which include algebraic, Einstein, Hamacher, Frank, and other types of t-conorms and t-norms. From that view point, in this paper the concepts of Archimedean t-conorm and t-norm are introduced to aggregate Pythagorean hesitant fuzzy information. Some new operational laws for Pythagorean hesitant fuzzy numbers based on Archimedean t-conorm and t-norm have been proposed. Using those operational laws, Archimedean t-conorm and t-norm-based Pythagorean hesitant fuzzy weighted averaging operator and weighted geometric operator are developed. Some of their desirable properties have also been investigated. Afterwards, these operators are applied to solve MCDM problems in Pythagorean hesitant fuzzy environment. The developed Archimedean aggregation operators are also applicable in Pythagorean fuzzy contexts also. To demonstrate the validity, practicality, and effectiveness of the proposed method, a practical problem is considered, solved, and compared with other existing method. 相似文献
43.
Shibaprasad Sen Mridul Mitra Ankan Bhattacharyya Ram Sarkar Friedhelm Schwenker Kaushik Roy 《Neural Processing Letters》2019,50(3):2281-2304
Feature selection through optimization techniques provides an interesting approach to minimize computational time with enhanced prediction capability, and 相似文献
44.
Bhowmik Showmik Sarkar Ram Nasipuri Mita Doermann David 《International Journal on Document Analysis and Recognition》2018,21(1-2):1-20
International Journal on Document Analysis and Recognition (IJDAR) - Separation of text and non-text is an essential processing step for any document analysis system. Therefore, it is important to... 相似文献
45.
46.
47.
48.
Kyungjung Kim Sarkar T.K. Salazar-Palma M. Romano S.-L. 《Antennas and Propagation, IEEE Transactions on》2002,50(3):277-283
Wavelet-like transformations have been used in the past to compress dense large matrices into a sparse system. However, they generally are implemented through a finite impulse response filter realized through the formulation of Daubechies (1992). A method is proposed to use a very high order filter (namely an ideal one) and use the computationally efficient fast Fourier transform (FFT) to carry out the multiresolution analysis. The goal here is to reduce the redundancy in the system and also guarantee that the wavelet coefficients drop off much faster. Hence, the efficiency of the new procedure becomes clear for very high order filters. The advantage of the FFT-based procedure utilizing ideal filters is that it can be computationally efficient and for very large matrices may yield a sparse matrix. However, this is achieved, as well known in the literature, at the expense of robustness, which may lead to a larger reconstruction error due to the presence of the Gibb's phenomenon. Numerical examples are presented to illustrate the efficiency of this procedure as conjectured in the literature 相似文献
49.
The results of an experimental investigation on the flow field in submerged jumps on horizontal rough beds, detected by an acoustic Doppler velocimeter, are presented. Experiments were conducted for the conditions of submerged jumps, having submergence factors from 0.96 to 1.85 and jet Froude numbers from 2.58 to 4.87, over rough beds of Nikuradse’s equivalent sand roughness equaling 0.49, 0.8, 1.86, and 3?mm. The vertical distributions of time-averaged velocity components, turbulence intensity components, and Reynolds stress at different streamwise distances from the sluice opening and the horizontal distribution of bed-shear stress are plotted. Vector plots of the flow field show that the rate of decay of jet velocity in a submerged jump increases with increase in bed roughness. The flow characteristics on rough beds, being different from those on smooth bed, are discussed from the point of view of similarity, growth of the length scale, and decay of the velocity and turbulence characteristics scales. The most important observation is that the flow in the fully developed zone is found to be self-preserving. 相似文献
50.
S. M. Islam Anupam Singha Roy Paramita Mondal Sanchita Mondal Manir Mubarak Dildar Hossain Saikat Sarkar 《应用聚合物科学杂志》2011,120(5):2743-2753
Three polymer‐anchored metal complexes (Co, Cu, and Pd) were synthesized and characterized. The catalytic performance of these complexes was tested for the oxidation of olefins and aromatic alcohols. These complexes showed excellent catalytic activity and high selectivity. These complexes selectively gave epoxides and aldehydes from olefins and alcohols, respectively. Individually, the effect of various solvents, oxidants, substrate oxidant molar ratios, temperatures, and catalyst amounts for the oxidation of cyclohexene and benzyl alcohol were studied. Under optimized reaction conditions, 96, 81, and 71% conversions of cyclohexene and 86, 79, and 73% conversions of benzyl alcohol were obtained with Co(II), Cu(II), and Pd(II) catalysts, respectively. The catalytic results reveal that these complexes could be recycled more than five times without much loss in activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献