全文获取类型
收费全文 | 2956篇 |
免费 | 57篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 49篇 |
综合类 | 3篇 |
化学工业 | 472篇 |
金属工艺 | 79篇 |
机械仪表 | 56篇 |
建筑科学 | 132篇 |
矿业工程 | 16篇 |
能源动力 | 56篇 |
轻工业 | 200篇 |
水利工程 | 25篇 |
石油天然气 | 14篇 |
无线电 | 222篇 |
一般工业技术 | 413篇 |
冶金工业 | 806篇 |
原子能技术 | 23篇 |
自动化技术 | 451篇 |
出版年
2022年 | 24篇 |
2021年 | 25篇 |
2020年 | 23篇 |
2019年 | 27篇 |
2018年 | 37篇 |
2017年 | 37篇 |
2016年 | 40篇 |
2015年 | 39篇 |
2014年 | 57篇 |
2013年 | 167篇 |
2012年 | 83篇 |
2011年 | 124篇 |
2010年 | 81篇 |
2009年 | 84篇 |
2008年 | 139篇 |
2007年 | 100篇 |
2006年 | 100篇 |
2005年 | 95篇 |
2004年 | 85篇 |
2003年 | 76篇 |
2002年 | 86篇 |
2001年 | 50篇 |
2000年 | 59篇 |
1999年 | 65篇 |
1998年 | 98篇 |
1997年 | 50篇 |
1996年 | 76篇 |
1995年 | 55篇 |
1994年 | 71篇 |
1993年 | 39篇 |
1992年 | 57篇 |
1991年 | 35篇 |
1990年 | 48篇 |
1989年 | 43篇 |
1988年 | 39篇 |
1987年 | 33篇 |
1986年 | 38篇 |
1985年 | 36篇 |
1984年 | 45篇 |
1983年 | 43篇 |
1982年 | 41篇 |
1981年 | 35篇 |
1980年 | 34篇 |
1979年 | 27篇 |
1978年 | 35篇 |
1977年 | 33篇 |
1976年 | 40篇 |
1975年 | 23篇 |
1974年 | 33篇 |
1973年 | 27篇 |
排序方式: 共有3017条查询结果,搜索用时 0 毫秒
11.
An algorithm is introduced which labels formants from the peaks of pole-focused spectra. A clustering procedure is first used to produce line segments of possible formants. These can be considered as anchor traces for the later processing. Rule-based labelling is then applied to provide final formant trace estimates. Experimental results show that the proposed algorithm offers improved formant labelling accuracy. 相似文献
12.
We report diffusion rates and equilibrium concentrations of water in a polyelectrolyte SPEES/PES film using ATR/FTIR spectroscopy. The data for water obtained by fitting spectral intensities to a dual mode diffusion model in the presence of different counter ions (at 0.2 mol dm−3) follow the order Li+>Cs+>Na+>Ca2+>K+. Diffusion is progressively slower for higher concentrations of NaCl (0.2-0.85 mol dm−3) and the NO3− counter anion leads to a faster diffusion rate than for Cl− at the same concentration. Both water uptake and diffusion rates are broadly consistent with expectations based on the differential degrees of swelling, caused by changes in the SO3−/SO3− interpolymer chain repulsive forces leading to a decrease in volume diffusion compared with the value for pure water. Direct spectral measurements of the degree of swelling confirm that the process does occur, although the order of the swelling amounts does not map directly onto that of the diffusion rates. This is probably because the interfacial dissociation processes are hydration dependent. 相似文献
13.
Measurement selection for parametric IC fault diagnosis 总被引:1,自引:0,他引:1
This article presents experimental results which show feedforward neural networks are well-suited for analog IC fault diagnosis. Boundary band data (BBD) measurement selection is used to reduce the computational overhead of the FFN training phase. We compare the diagnostic accuracy between traditional statistical classifiers and feedforward neural networks trained with various measurement selection criteria. The feedforward networks consistently perform as well as or better than the other classifiers in term of accuracy. Training using BBD consistently reduces the FFN training efforts without degrading the performance. Experimental results suggest that feedforward networks provide a cost efficient method for IC fault diagnosis in a large scale production testing environment.This work is supported by NSF-IUC CDADIC, Project 90-1. 相似文献
14.
Rattok Jack; Ross Barbara; Ben-Yishay Yehuda; Ezrachi Ora; Silver Saralyn; Lakin Phyllis; Vakil Eli; Piasetsky Eugene; Zide Ellen; Diller Leonard 《Canadian Metallurgical Quarterly》1992,6(4):395
Within a clinical demonstration program, 59 traumatically brain-injured patients were treated with 1 of 3 mixes of treatment. Mix 1 included cognitive remediation (CGR), small-group interpersonal (SGI) communication training, therapeutic community activities, and personal counseling. Mix 2 was similar to Mix 1 but stressed SGI exercises and eliminated CGR. Mix 3 emphasized CGR and eliminated SGI exercises. The efficacy of the treatment mixes was evaluated with performance on neuropsychological tests, improved independence in functional activities, measures of intra- and interpersonal functioning, and vocational outcome. Ss' participation in the program, irrespective of treatment mix, yielded improvements in (1) self-image, (2) quality of interpersonal relatedness and interaction, (3) involvement with others in naturalistic settings, and (4) vocational outcome. Overall, data point to the superiority of the balanced mix (Mix 1) over Mixes 2 and 3. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
15.
The resources of various settings located in one geographic area of a state were linked in an attempt to resolve educational problems. Using the concept of collegium as the mechanism for working together, the assumptions governing these efforts are presented, rationale for successes and failures are discussed, and suggestions are made on how such undertakings may relate to the field of school psychology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
16.
The role of gas phase CH3 radicals in the oxidative coupling of CH4 over 1 wt% Sr/La2O3 is supported by the observations that (i) this is a very effective catalyst for the generation of CH3 · radicals and (ii) the concentration of CH3 · radicals increases with temperature over the range of 450 °C–800 °C. 相似文献
17.
18.
Julian P. Wright Alan G. Jack 《International journal for numerical methods in engineering》1994,37(11):1841-1861
Presented in this paper are the theoretical aspects of node addition to a non-convex, multiboundary mesh of tetrahedral elements as used in finite element modelling. The method used is derived from Watson1 and Shenton and Cendes2 and is extended to deal with node addition on inter-material boundaries. Several situations are identified that result in an illegal insertion polyhedron (IP), these could be caused by the ‘constrained’ nature of the mesh, adjacent objects with different material properties, or degenerate node configurations. A new Delaunay algorithm is described that checks for illegal cases of the IP and then corrects them, this checking relies on the consistent ordering of the element nodes. It is shown that a particular type of illegal IP can easily be identified and corrected using this technique. The Delaunay algorithm is then applied to automatic mesh generation, and modification to the basic Delaunay algorithm is described so that previously meshed edges and faces of the current object being meshed are not deleted during the addition of subsequent nodes. This ‘protection’ method only becomes viable by recognizing the node ordering sense of the IP faces. 相似文献
19.
Pan J.S. McInnes F.R. Jack M.A. 《Vision, Image and Signal Processing, IEE Proceedings -》1996,143(1):67-71
A bound for a Minkowski metric based on Lp distortion measure is proposed and evaluated as a means to reduce the computation in vector quantisation. This bound provides a better criterion than the absolute error inequality (AEI) elimination rule on the Euclidean distortion measure. For the Minkowski metric of order n, this bound contributes the elimination criterion from the L1 metric to L n metric. This bound can also be an extended quadratic metric which can be a hidden Markov model (HMM) with a Gaussian mixture probability density function (PDF). In speech recognition, the HMM with the Gaussian mixture VQ codebook PDF has been shown to be a promising method 相似文献
20.
Jack E. Snell 《Fire Technology》1994,30(3):357-365
The FORUM for International Cooperation on Fire Research is an informal group of people committed to fire research and the application of fire-research results. Since it was formed in 1988, the FORUM has brought together organizational leaders who direct resources for fire research throughout the world. This article is reprinted from the Nordic Fire Safety Engineering Symposium, Development and Verification of Tools for Performance Codes, August 30–September 1, 1993, in Espoo, Finland. 相似文献