全文获取类型
收费全文 | 165篇 |
免费 | 1篇 |
专业分类
化学工业 | 15篇 |
机械仪表 | 3篇 |
建筑科学 | 5篇 |
能源动力 | 13篇 |
轻工业 | 15篇 |
水利工程 | 5篇 |
无线电 | 8篇 |
一般工业技术 | 29篇 |
冶金工业 | 25篇 |
原子能技术 | 1篇 |
自动化技术 | 47篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 2篇 |
2013年 | 5篇 |
2012年 | 3篇 |
2011年 | 11篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 5篇 |
2007年 | 2篇 |
2006年 | 3篇 |
2005年 | 7篇 |
2004年 | 8篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 20篇 |
1997年 | 2篇 |
1996年 | 5篇 |
1995年 | 8篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1991年 | 3篇 |
1989年 | 1篇 |
1988年 | 4篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
排序方式: 共有166条查询结果,搜索用时 15 毫秒
51.
Borghi R Guattari G de la Torre L Gori F Santarsiero M 《Journal of the Optical Society of America. A, Optics, image science, and vision》2003,20(9):1763-1770
The problem of recovering the coherence features of a partially coherent quasi-monochromatic scalar optical source, starting solely from intensity measurements on the emitted beam, is addressed in the most general way, under the paraxial approximation. In particular, it is shown that on expanding the beam emitted by the source as a bundle of partially correlated Hermite-Gaussian beams, the correlation coefficients can be recovered, in principle, simply by performing scalar products between transverse intensity distributions and suitably defined functions. 相似文献
52.
Cavallini G Parentini I Di Stefano R Maccheroni M Masini M Pollera M Gori Z Mosca F Bergamini E 《Lipids》2002,37(9):913-916
Dolichol (D) levels increase dramatically in older tissue. An understanding of the exchangeability of D between tissues may
be essential in order to understand the mechanism of the abnormal accumulation associated with aging. The question was investigated
by the use of organ transplantation. D-poor hearts donated by 3-mon-old and D-rich by 22-mon-old male Lewis rats were transplanted
heterotopically in 3-mon-old syngenic recipients, whose peripheral tissues and liver were poor in D. Native and transplanted
hearts were taken 7 and 21 d after surgery. Native hearts of 3-mon- and 22-mon-old male Lewis rats served as control. D concentration
and quantity were higher in older than in younger native hearts as expected. In the transplanted hearts, the quantity of D
was unchanged, irrespective of the age of the donor and of the time of transplantation, whereas D concentration increased
because of the remarkable disuse atrophy. No changes in D were observed in recipients’ tissues. It is concluded that dolichol
is not redistributed via circulation from the transplanted heart to the tissues and liver of the younger recipient. 相似文献
53.
An electronic nose based on an array of 6 metal oxide semiconductor sensors was used, jointly with artificial neural network (ANN) method, to classify Pecorino cheeses according to their ripening time and manufacturing techniques. For this purpose different pre-treatments of electronic nose signals have been tested. In particular, four different features extraction algorithms were compared with a principal component analysis (PCA) using to reduce the dimensionality of data set (data consisted of 900 data points per sensor). All the ANN models (with different pre-treatment data) have different capability to predict the Pecorino cheeses categories. In particular, PCA show better results (classification performance: 100%; RMSE: 0.024) in comparison with other pre-treatment systems. 相似文献
54.
This paper describes the Remi‐Irpet macroeconometric multisectoral model. The Remi‐Irpet, based on an input‐output core structure, has its most distinctive feature in the modelling of vertical pecuniary externalities à la Fujita‐Krugman‐Venables which represents the core dynamization mechanism. Our contribution first presents the theoretical background of the model. Second, we present a simulation exercise performed through the model in which we evaluate the structural impact of incoming FDIs for Tuscany. The impact analysis is defined in terms of (i) change in the overall productive capacity and (ii) medium‐term changes in prices and productivity, driven by the changes in the accessibility to labour and intermediate inputs. 相似文献
55.
Gori M Bergfeldt B Pfrang-Stotz G Reichelt J Sirini P 《Journal of hazardous materials》2011,189(1-2):435-443
Short term natural weathering was applied on municipal solid waste (MSW) and wood waste incinerator bottom ash (BA). The materials were analysed at different steps of treatment and characterized for chemical and mineralogical composition. Both short and long term leaching behaviour of main elements and heavy metals were investigated as well. Lead, zinc and copper were the main heavy metals to be released. After 12 weeks of treatment the concentration of leached zinc decreased. Lead concentration was not found to be influenced by pH and decreased only for the biomass samples. Weathering did not have beneficial effects on copper leaching, which was well described by complexation processes with DOC. The findings from the experimental campaign indicated that weathering reactions improved the mineral stability of the analysed materials but, in contrast with previous works, the treatment was not sufficient to guarantee pH stability and to comply with leaching law limits. 相似文献
56.
On the problem of local minima in recurrent neural networks 总被引:2,自引:0,他引:2
Many researchers have recently focused their efforts on devising efficient algorithms, mainly based on optimization schemes, for learning the weights of recurrent neural networks. As in the case of feedforward networks, however, these learning algorithms may get stuck in local minima during gradient descent, thus discovering sub-optimal solutions. This paper analyses the problem of optimal learning in recurrent networks by proposing conditions that guarantee local minima free error surfaces. An example is given that also shows the constructive role of the proposed theory in designing networks suitable for solving a given task. Moreover, a formal relationship between recurrent and static feedforward networks is established such that the examples of local minima for feedforward networks already known in the literature can be associated with analogous ones in recurrent networks. 相似文献
57.
58.
G Marchetti A Gori L Catozzi L Vago M Nebuloni MC Rossi AD Esposti A Bandera F Franzetti 《Canadian Metallurgical Quarterly》1998,36(6):1512-1517
We compared the sensitivities and specificities of four nested PCR assays for the detection of Mycobacterium tuberculosis from formalin-fixed, paraffin-embedded tissues. Thirty-seven autopsy samples from human immunodeficiency virus-positive patients were analyzed: 15 were M. tuberculosis positive, 11 served as negative controls, and 11 were Ziehl-Neelsen positive without cultural confirmation of M. tuberculosis. Three genomic sequences (mtp40, 65-kDa antigen gene, and IS6110) with different molecular masses and numbers of repetitions within the M. tuberculosis genome were targeted. On the IS6110 sequence, two fragments of different sizes (106 and 123 bp, respectively) were amplified with two separate pairs of primers. The highest sensitivity rates were obtained by amplifying the highly repetitive IS6110 insertion sequence, and the different primers tested showed a sensitivity ranging from 80 to 87%. Amplification of the large 223-bp fragment of the mtp40 sequence present in a single copy in the M. tuberculosis genome yielded a high rate of false-negative results, ranging from 66 to 80%. A poor sensitivity (from 47 to 60%) was also shown by PCR amplification of the 142-bp 65-kDa antigen gene. All the PCRs except that for the 65-kDa antigen gene showed a specificity of 100%. Moreover, different results were obtained with different dilutions of DNA, and DNA concentrations of 1 and 3 microg yielded the highest sensitivities depending upon which protocol was used. Application of the PCRs to the Ziehl-Neelsen-positive, culture-negative samples confirmed the sensitivities of the PCRs obtained with the control samples. In conclusion, PCR can successfully be used to detect M. tuberculosis from paraffin-embedded tissues and can be particularly useful in the validation of a diagnosis of tuberculosis in clinical settings in which the diagnosis is uncertain. However, the efficacy of PCR strictly depends on several amplification parameters such as DNA concentration, target DNA size, and the repetitiveness of the amplified sequence. 相似文献
59.
In this paper we explore the expressive power of recurrent networks with local feedback connections for symbolic data streams. We rely on the analysis of the maximal set of strings that can be shattered by the concept class associated to these networks (i.e. strings that can be arbitrarily classified as positive or negative), and find that their expressive power is inherently limited, since there are sets of strings that cannot be shattered, regardless of the number of hidden units. Although the analysis holds for networks with hard threshold units, we claim that the incremental computational capabilities gained when using sigmoidal units are severely paid in terms of robustness of the corresponding representation. 相似文献
60.
Tangential and radial shrinkage of 43 tropical hardwoods have been determined at different moisture intervals between green and oven dry condition. 相似文献