全文获取类型
收费全文 | 512篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
化学工业 | 126篇 |
金属工艺 | 8篇 |
机械仪表 | 23篇 |
建筑科学 | 20篇 |
矿业工程 | 2篇 |
能源动力 | 14篇 |
轻工业 | 49篇 |
水利工程 | 7篇 |
石油天然气 | 2篇 |
无线电 | 44篇 |
一般工业技术 | 92篇 |
冶金工业 | 15篇 |
原子能技术 | 5篇 |
自动化技术 | 101篇 |
出版年
2023年 | 2篇 |
2022年 | 10篇 |
2021年 | 14篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 8篇 |
2017年 | 9篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 11篇 |
2013年 | 26篇 |
2012年 | 30篇 |
2011年 | 43篇 |
2010年 | 21篇 |
2009年 | 26篇 |
2008年 | 30篇 |
2007年 | 35篇 |
2006年 | 41篇 |
2005年 | 26篇 |
2004年 | 19篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 9篇 |
1998年 | 6篇 |
1997年 | 12篇 |
1996年 | 9篇 |
1995年 | 12篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有515条查询结果,搜索用时 0 毫秒
41.
42.
Jean-Luc Dion Gaël Chevallier Nicolas Peyret 《Mechanical Systems and Signal Processing》2013,34(1-2):106-115
This paper deals with the damping caused by friction in joints. A new test bench is presented and justified by comparisons made with devices described in the literature. The purpose of this academic bench is to measure the damping induced by partial slip and friction in a planar joint. Moreover, allows uncoupling normal static and dynamic tangential forces. A new method for so-called stopped-sine excitation was developed. It allows more precise monitoring of the evolution of the vibration frequency and damping of non-linear modes. This method is associated with piezoelectric exciters for greater efficiency when stopping excitation. A large number of experimental results are presented and discussed. They are used to characterize the damping induced by micro-sliding in the bonds. 相似文献
43.
The present study investigates the performance of eccentrically loaded columns externally strengthened with different carbon fiber-reinforced polymer (CFRP) systems. The 10 specimens were representative-scale square columns made of normal-strength concrete with substandard (internal) reinforcement details that were designed to represent old building structural columns. Eight columns were upgraded by four types of commercially available systems of external reinforcement, using plates, unidirectional or bi-directional composite fabrics. It was considered necessary to get information on a wide spectrum of carbon fiber-reinforcement systems in order to provide a satisfactory set of experimental data for validating future suitable retrofitting design methods. Experimental results presented in this paper show that a significant improvement of the strength capacity, deformation capacity and ductility of columns can result of the CFRP application, but the observed gains strongly depend on the reinforcement systems. 相似文献
44.
The learning of complex relationships can be decomposed into several neural networks. The modular organization is determined
by prior knowledge of the problem that permits to split the processing into tasks of small dimensionality. The sub-tasks can
be implemented with neural networks, although the learning examples cannot be used anymore to supervise directly each of the
networks. This article addresses the problem of learning in a modular context, developing in particular additive compositions. A simple rule allows defining efficient training, and combining, for example, several Supervised-SOM networks. This technique
is important because it introduces interesting generalizations in many modular compositions, permitting data fusion or sequential
combinations of neural networks.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
45.
46.
Species identification of meat products by ELISA 总被引:4,自引:0,他引:4
Inès Giovannacci Cécile Guizard Martine Carlier Valérie Duval Jean-Luc Martin & Claude Demeulemester 《International Journal of Food Science & Technology》2004,39(8):863-867
ELISA methods used in this study are proved to detect low contents of animal species (pork, beef, sheep and poultry), even in highly processed foods. They present the advantages of being robust, cheap and easy to perform. Nevertheless, F factors, determining the threshold values of the test, need to be validated for each species. 相似文献
47.
Synthesis of few-layered graphene by ion implantation of carbon in nickel thin films 总被引:1,自引:0,他引:1
Baraton L He Z Lee CS Maurice JL Cojocaru CS Gourgues-Lorenzon AF Lee YH Pribat D 《Nanotechnology》2011,22(8):085601
The synthesis of few-layered graphene is performed by ion implantation of carbon species in thin nickel films, followed by high temperature annealing and quenching. Although ion implantation enables a precise control of the carbon content and of the uniformity of the in-plane carbon concentration in the Ni films before annealing, we observe thickness non-uniformities in the synthesized graphene layers after high temperature annealing. These non-uniformities are probably induced by the heterogeneous distribution/topography of the graphene nucleation sites on the Ni surface. Taken altogether, our results indicate that the number of graphene layers on top of Ni films is controlled by the nucleation process on the Ni surface rather than by the carbon content in the Ni film. 相似文献
48.
The characterization of cord blood hemoglobin at the molecular level is a daunting challenge because hemoglobin F (HbF) and hemoglobin A (HbA) coexist in neonatal blood. We developed and validated a method using electrospray time-of-flight mass spectrometry (ES-TOF-MS) that measures, in a single analysis, relative levels of glycated and acetylated hemoglobin and allows the calculation of relative proportions of HbA, HbF(0), and HbF(1) in cord blood. Specific sections of acquired spectra were deconvoluted using a maximum entropy-based approach to true mass scale spectra. Mass precisions were less than 3 ppm with similar accuracies. Intra-interday precisions for α- and γ-chain glycation levels were 2.10%/3.72% and 2.75%/6.79%, respectively. The linearity of the α-chain glycation response was excellent (r(2) = 0.9990). We performed sample analysis on 39 cord blood specimens and found that the glycated α- and γ-chain levels were 2.27 ± 0.21% and 2.38 ± 0.29%, respectively, while the acetylated (G)γ and (A)γ-chain levels were 8.48 ± 0.53% and 7.14 ± 0.74%, respectively. We observed three types of HbF distinguishable by the intensities of γ-chain variants. Two-thirds of cord blood specimens were classified as HbF(I) with an intensity ratio (G)γ/(A)γ of 1.90 ± 0.12. For HbF(II) type (10/39 neonates), the intensity ratio of (G)γ/(A)γ was 3.71 ± 0.28. For three neonates with HbF(III), no (A)γ-chain was detected. 相似文献
49.
Walter Wildi Janusz Dominik Jean-Luc Loizeau Richard Linn Thomas Pierre-Yves Favarger Laurence Haller Antoine Perroud Christophe Peytremann 《Lakes & Reservoirs: Research and Management》2004,9(1):75-87
This paper quantifies sediment contamination by heavy metals in four reservoirs and one lake located downstream from major urban areas in Switzerland. The waterbodies include the Wettingen Reservoir (located on the Limmat River downstream from Zürich), the Klingnau Reservoir (on the lower Aare River), the Wohlen Reservoir (downstream from Berne), the Verbois Reservoir (downstream from Geneva) and Vidy Bay (Lake Geneva, city of Lausanne). For all sediment cores and contaminants, a trend is observed from high contaminant values in the lower part of the cores, decreasing to lower concentrations in the upper part of the cores. However, for each site and each element, specific features are recognized. Applying the criteria of the Swiss ordinance on soil protection, all sediment cores must be classified as contaminated by one or more contaminants and at variable levels. From these data, it is concluded that: reservoirs and lakes located downstream from major urban centres in Switzerland have accumulated significant volumes of contaminated sediments in the past, representing the largest, but not the most intensely, contaminated sites on a national scale; the main environmental risk is remobilization of the contaminants and their return to the food chain, particularly by infiltration into the groundwater; and although the processes of remobilization are identified, the conditions of occurrence and the amplitude of the processes are still poorly known. Different options of reservoir and lake sediment management also are discussed and further research topics defined. 相似文献
50.
Winicjusz Drozdowski Andrzej J. Wojtowicz Dariusz Wi
niewski Piotr Szupryczy
ski Sebastian Janus Jean-Luc Lefaucheur Zhenhui Gou 《Journal of Alloys and Compounds》2004,380(1-2):146-150
Radioluminescence and UV-excited photoluminescence spectra, photoluminescence time profiles, thermoluminescence glow curves and gamma-excited energy spectra (determining scintillation light yields) of several Lu2SiO5:Ce and Y2SiO5:Ce samples were recorded. The results are analyzed with attention focused on possible correlations between trap distributions, VUV responses, and light yields. The aspect of two distinct sites occupied by Ce3+ ions is also discussed. 相似文献