全文获取类型
收费全文 | 360篇 |
免费 | 4篇 |
专业分类
电工技术 | 13篇 |
化学工业 | 93篇 |
金属工艺 | 7篇 |
机械仪表 | 3篇 |
建筑科学 | 1篇 |
能源动力 | 9篇 |
轻工业 | 23篇 |
水利工程 | 2篇 |
无线电 | 57篇 |
一般工业技术 | 48篇 |
冶金工业 | 88篇 |
原子能技术 | 8篇 |
自动化技术 | 12篇 |
出版年
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 3篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 1篇 |
2015年 | 2篇 |
2014年 | 5篇 |
2013年 | 8篇 |
2012年 | 7篇 |
2011年 | 7篇 |
2010年 | 14篇 |
2009年 | 10篇 |
2008年 | 8篇 |
2007年 | 13篇 |
2006年 | 10篇 |
2005年 | 10篇 |
2004年 | 9篇 |
2003年 | 7篇 |
2002年 | 12篇 |
2001年 | 13篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 30篇 |
1997年 | 22篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 17篇 |
1993年 | 11篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 14篇 |
1984年 | 4篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 3篇 |
1977年 | 2篇 |
1976年 | 6篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有364条查询结果,搜索用时 312 毫秒
1.
Network information criterion-determining the number of hiddenunits for an artificial neural network model 总被引:6,自引:0,他引:6
The problem of model selection, or determination of the number of hidden units, can be approached statistically, by generalizing Akaike's information criterion (AIC) to be applicable to unfaithful (i.e., unrealizable) models with general loss criteria including regularization terms. The relation between the training error and the generalization error is studied in terms of the number of the training examples and the complexity of a network which reduces to the number of parameters in the ordinary statistical theory of AIC. This relation leads to a new network information criterion which is useful for selecting the optimal network model based on a given training set. 相似文献
2.
As a model for organic ferromagnetism in a one-dimensional system, substituted polyacetylenes are re-considered on the basis of the molecular orbital (MO) and the crystal orbital (CO) methods. The semiempirical MO calculations with configuration interaction for the dimer model show that the exchange interaction on poly[(4-oxyphenyl)acetylene] (1) is negative in spite of Ovchinnikov's prediction, due to the direct interaction between the adjacent pendant spins. On the other hand, it is shown that a polyacetylene chain with phenoxy radicals as pendants on every other active site can become a one-dimensional feromagnet. Moreover, the CO calculations by means of the unrestricted Hartree-Fock method give a theoretical background for the realization of a ground state with macroscopic spin alignment on the improved model chain. 相似文献
3.
4.
5.
6.
Zempachi Ogumi Hiroya Yamashita Koji Nishio Zen-Ichiro Takehara Shiro Yoshizawa 《Electrochimica acta》1983,28(11):1687-1693
The feasibility of a solid polymer electrolyte (SPE) method for Kolbe type reactions was investigated by using Pt-SPE composed with Nafion 415 and platinum. The Kolbe reaction of acetic acid proceeded effectively on one side and both sides Pt-SPE composites. The lower current efficiency was observed on the latter than on the former. Neat acetic acid could also be electrolysed on both sides SPE though the cell voltage was fairly high.A methanolic solution of monomethyl adipate was electrolysed to give dimethyl sebacate on both sides Pt-SPE according to the Brown-Walker reaction. The current efficiency and the terminal voltage increased with the concentration of monomethyl adipate. Pt-SPE behaved as an active electrode of a high roughness factor, eg about 6, for the Kolbe reaction of acetate. 相似文献
7.
In the copolymerization of phenylacetylene with various acetylenes catalysed by WCl6·Ph4Sn, the relative reactivity of monomer decreased with increasing steric effect of monomer, e.g. HC Cn-Bu, HC Cn-Hex > HC CPh, HC Cs-Bu > HC Ct-Bu, MeCCPh, CICCPh. While 1-chloro-2-phenylacetylene (a disubstituted acetylene) showed high reactivity in the homopolymerization by Mobased catalysts, the reactivity was remarkably depressed in the presence of phenylacetylene as comonomer. Based on these results, the relative reactivity of the acetylenic monomers in copolymerization was explained in terms of competitive coordination of monomers to the propagating end. 相似文献
8.
Yu-ichi Yoshizawa Kiyoshi Hirao Shuzo Kanzaki 《Journal of the American Ceramic Society》2004,87(11):2147-2149
The mechanical properties of a textured alumina made by high-temperature deformation of normal-purity sintered alumina have been investigated. The textured alumina shows very high bending strength and extremely high fracture toughness. Fracture toughness of more than 10 MPa·m1/2 was measured by the single-edge precracked beam method, and even using the single-edge V-notched beam method, toughness of over 8 MPa·m1/2 was obtained. This high fracture toughness was attributed to a large number of aligned small platelike grains of the textured structure enhancing the grain bridging effect. 相似文献
9.
An integrated optical-disk pickup that uses a focusing grating coupler with a numerical aperture of 0.45 (a focal length of 1.0 mm and an aperture of 1.0 mm × 0.8 mm) was developed, and the readout signal on an International Standards Organization (ISO) -formatted 90-mm optical disk was detected by the pickup. The signal-amplitude ratio of the minimum-limit data pattern to the maximum was 0.53 on the innermost track. It meets the requirement on the signal resolution for optical-disk storage devices. 相似文献
10.
Clinicopathological significance of intratubular giant macrophages in progressive glomerulonephritis
T Oda O Hotta Y Taguma H Kitamura H Sugai S Onodera I Horigome K Suzuki Y Shouji T Furuta S Chiba N Yoshizawa H Nagura 《Canadian Metallurgical Quarterly》1998,53(5):1190-1200
Very large macrophages, which we have termed "giant macrophages" (G-M phi), have been found in renal tubules, some containing cytoplasmic vacuoles. To elucidate their pathophysiological roles, we examined renal biopsy tissues from various primary glomerulonephritis (GN) and tubulointerstitial nephritis (TIN) using immunohistochemistry with monoclonal antibodies against M phi and other cell surface markers. Giant macrophages were absent or rare in TIN, minimal change nephrotic syndrome, and minor glomerular abnormalities, but G-M phi was plentiful in progressive glomerulonephrides such as IgA nephropathy with crescents, membranoproliferative GN, focal segmental glomerulosclerosis, and especially in crescentic GN. These G-M phi were usually seen in the lumen of renal tubules, but occasionally were found in the Bowman's spaces and glomerular tufts, and similar cells were also found in urine. Moreover, they frequently made contact with tubular epithelial cells expressing intercellular adhesion molecule-1, and the tubular epithelial cells in such lesions often had degenerative changes. Giant M phi may damage tubular epithelial cells from the luminal side. Phenotypically, G-M phi showed activated (CD71+) and mature (25F9+) characteristics along with features of M phi (CD68+), and the cytoplasm contained a great deal of lipids. The numbers of G-M phi in renal tissues closely correlated with the degree of hematuria (rho = 0.5, P < 0.001), serum creatinine value (r = 0.63, P < 0.001) in GN patients (N = 96) and with proteinuria in IgA nephropathy patients (r = 0.89, P < 0.001, N = 27). These data suggest that G-M phi are M phi that were activated and matured in certain active inflammatory sites, which flowed into tubules and then into urine. Thus, the existence of G-M phi in biopsy tissue or urine reflect the activity of GN and may have a predictive value for the progression of GN. 相似文献