全文获取类型
收费全文 | 2385篇 |
免费 | 125篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 31篇 |
综合类 | 9篇 |
化学工业 | 740篇 |
金属工艺 | 36篇 |
机械仪表 | 77篇 |
建筑科学 | 109篇 |
矿业工程 | 2篇 |
能源动力 | 95篇 |
轻工业 | 289篇 |
水利工程 | 9篇 |
石油天然气 | 5篇 |
武器工业 | 1篇 |
无线电 | 211篇 |
一般工业技术 | 424篇 |
冶金工业 | 79篇 |
原子能技术 | 18篇 |
自动化技术 | 381篇 |
出版年
2024年 | 4篇 |
2023年 | 30篇 |
2022年 | 150篇 |
2021年 | 175篇 |
2020年 | 62篇 |
2019年 | 66篇 |
2018年 | 86篇 |
2017年 | 75篇 |
2016年 | 77篇 |
2015年 | 72篇 |
2014年 | 115篇 |
2013年 | 174篇 |
2012年 | 112篇 |
2011年 | 184篇 |
2010年 | 135篇 |
2009年 | 117篇 |
2008年 | 120篇 |
2007年 | 107篇 |
2006年 | 88篇 |
2005年 | 68篇 |
2004年 | 64篇 |
2003年 | 57篇 |
2002年 | 54篇 |
2001年 | 33篇 |
2000年 | 23篇 |
1999年 | 29篇 |
1998年 | 29篇 |
1997年 | 28篇 |
1996年 | 22篇 |
1995年 | 17篇 |
1994年 | 16篇 |
1993年 | 12篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1985年 | 5篇 |
1984年 | 15篇 |
1983年 | 7篇 |
1982年 | 7篇 |
1981年 | 5篇 |
1980年 | 3篇 |
1979年 | 7篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1974年 | 4篇 |
1967年 | 3篇 |
1966年 | 3篇 |
排序方式: 共有2516条查询结果,搜索用时 15 毫秒
71.
Valeria Artale Mario Collotta Cristina Milazzo Giovanni Pau Angela Ricciardello 《Journal of Intelligent and Robotic Systems》2016,84(1-4):5-19
Modern aerospace vehicles are expected to have non-conventional flight envelopes and then, in order to operate in uncertain environments, they must guarantee a high level of robustness and adaptability. A Neural Network (NN) controller, with real-time learning capability, can be used in applications with manned or unmanned aerial vehicles. In this paper a novel real-time control system, based on a NN model, in order to control the trajectories of a hexacopter is proposed. The proposed NN is optimized by the analytical calculation of the embedding parameters. The paper shows a performance evaluation, through a real experimental testbed, of the proposed approach in terms of error measures and computation of the angular velocities of the hexacopter. 相似文献
72.
The territorial capital of regions is an important determinant of growth, but also of the impact of EU Cohesion Policy. First, because it can act as a filter, enhancing the impact of regional policies. Second, the latter can help building territorial capital which, in turn, will foster regional development. This work analyses the medium and long-run relationship between the territorial capital of EU NUTS 3 regions and Cohesion Policy using data from the programming period 2000–2006. Results point out complementarities between different territorial assets of regions and the impact of EU regional policy: Cohesion Policy effectiveness is higher when investments are focused on the assets complementary to those already abundant in the region. 相似文献
73.
74.
Pintore Giovanni Ganovelli Fabio Pintus Ruggero Scopigno Roberto Gobbetti Enrico 《计算可视媒体(英文)》2018,4(4):367-383
Computational Visual Media - We present a novel approach to automatically recover, from a small set of partially overlapping spherical images, an indoor structure representation in terms of a 3D... 相似文献
75.
Filippo Fabbri Francesca Rossi Manuela Melucci Ilse Manet Giovanni Attolini Laura Favaretto Massimo Zambianchi Giancarlo Salviati 《Nanoscale research letters》2012,7(1):680
A new class of nanostructured hybrid materials is developed by direct grafting of a model thiophene-based organic dye on the surface of 3C-SiC/SiO2 core/shell nanowires. TEM-EDX analysis reveals that the carbon distribution is more spread than it would be, considering only the SiC core size, suggesting a main contribution from C of the oligothiophene framework. Further, the sulfur signal found along the treated wires is not detected in the as-grown samples. In addition, the fluorescent spectra are similar for the functionalized nanostructures and T3Pyr in solution, confirming homogeneous molecule grafting on the nanowire surface. Chemical and luminescence characterizations confirm a homogeneous functionalization of the nanowires. In particular, the fluorophore retains its optical properties after functionalization. 相似文献
76.
Giovanni Caprioli Michael G. Cahill Sauro Vittori Kevin J. James 《Food Analytical Methods》2014,7(7):1367-1372
Potatoes produce biologically active secondary metabolites like glycoalkaloids and their aglycons, which may have both adverse and beneficial effects in the diet. A new analytical method that uses liquid chromatography–mass spectrometry (LTQ-Orbitrap) has been developed for the analysis of glycoalkaloids and their aglycons in potato samples. Two glycoalkaloids, α-solanine and α-chaconine, and two aglycons, demissidine and solasodine, were quantified in potato samples. Samples were extracted using methanol, purified on an SPE Strata C18 cartridge, and then analyzed in HPLC–mass spectrometry (LTQ-Orbitrap) with the FTMS operating in full scan at a resolving power of 30,000 (FWHM), enabling the detection and accurate mass measurement and with the ITMS mode operating in MRM (multiple reaction monitoring) for glycoalkaloids and their aglycons using the [M + H]+ ions and their optimized collision energies. After validation, the method was applied to screen different type of potatoes, and some cooking experiment were conducted. 相似文献
77.
The escalation in product recalls in recent years is attributed to the rise of globalisation and associated challenges of offshoring. Extant SCM research suggests that product recalls have a significant negative impact on financial performance, but gaps exist relative to the managerial actions to minimise their impact. Recall response strategies have become more important in the press, given that a single recall may result in the mandatory withdrawal of millions of products from the market, with firms incurring enormous logistics costs and brand damage. In this study, we address this gap in the research, and using a measure of product recall defined as the volume of products withdrawn from the market due to product quality failure. We explore the scale of the recall in the context of pharmaceutical sector global sourcing strategies, exploring whether the variation in global sourcing decisions not only increases the likelihood of a recall, but also influences the capability to minimise the total cost of recall. Our results suggest that offshore outsourcing and captive offshoring have opposite effects in terms of their influence on the magnitude of product recall. We summarise the implications through a compelling set of insights for future global sourcing strategy research themes. 相似文献
78.
Accurate measurement of institutional research productivity should account for the real contribution of the research staff to the output produced in collaboration with other organizations. In the framework of bibliometric measurement, this implies accounting for both the number of co-authors and each individual’s real contribution to scientific publications. Common practice in the life sciences is to indicate such contribution through the order of author names in the byline. In this work, we measure the distortion introduced to university-level bibliometric productivity rankings when the number of co-authors or their position in the byline is ignored. The field of observation consists of all Italian universities active in the life sciences (Biology and Medicine). The analysis is based on the research output of the university staff over the period 2004–2008. Based on the results, we recommend against the use of bibliometric indicators that ignore co-authorship and real contribution of each author to research outputs. 相似文献
79.
The Italian economy is characterised by a large number of micro-firms and small firms and by a long-lasting gap between North and South Italy. Therefore, global shocks – such as the Great Recession – have had a heterogeneous impact at the local level: the collapse in private demand was unequally distributed across different products, services and regions. The aim of this paper, therefore, is to evaluate the impact of the Great Recession on firm's survival for the universe of Italian firms in the light of two relevant indicators: local exposure to crisis and local demand shocks. The results suggest a strong negative impact of local demand shocks on the survival of firms, whereas the degree of exposure to the crisis generally has a weak effect. 相似文献
80.
Giovanni Rinaldi George Crossley Ed Mackay Ian Ashton Max Campbell Tim Wood Lars Johanning 《国际能源研究杂志》2019,43(13):7316-7335
The Maldives is a group of tropical atolls, considered globally to be one of the most desirable holiday destinations. There is an urgent requirement to decrease their dependency on fossil fuels that are currently the main source of energy, and a number of renewable energy alternatives are being evaluated. Among these, due to the favorable oceanographic and bathymetric conditions, ocean thermal energy conversion (OTEC) systems represent a viable opportunity for clean and reliable power. However, the stresses the OTEC platform will need to endure during adverse environmental conditions are not well defined. The magnitude of these stresses will then have a direct influence on the design of the OTEC device. In order to overcome this uncertainty, this paper uses hindcast data sets from global weather and ocean models to assess the metocean conditions of the Maldives, with particular reference to extreme conditions. After selecting a suitable location for the deployment of the devices, return values calculated using the peaks‐over‐threshold (POT) methodology are estimated for wind, waves, and currents. The 100‐year return value for the significant wave height is found to be 4.5 m, with a joint occurrence of energy periods between 7.5 and 8.5 seconds, whereas the 100‐year return wind has a velocity of 17.8 m/s and the 100‐year return current of 1.9 m/s. The directionality of these extreme events is also considered, showing the southern and western sub‐quadrants as the prevailing sources, which provides essential information for positioning of the platform. Additional evaluations of tropical revolving storms (TRS) and variations in temperature and salinity patterns are also provided over a 1500‐m water column; temperature varies by approximately 24°C, and salinity by around 2 ppt, showing the suitability of OTEC platforms in the Maldives. This work is therefore of interest to offshore renewable energy stakeholders interested in developing a project in the Maldives or those conducting an analogous analysis in other locations. 相似文献