全文获取类型
收费全文 | 1368篇 |
免费 | 67篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 41篇 |
化学工业 | 418篇 |
金属工艺 | 12篇 |
机械仪表 | 30篇 |
建筑科学 | 41篇 |
矿业工程 | 3篇 |
能源动力 | 74篇 |
轻工业 | 154篇 |
石油天然气 | 2篇 |
无线电 | 111篇 |
一般工业技术 | 292篇 |
冶金工业 | 33篇 |
原子能技术 | 10篇 |
自动化技术 | 216篇 |
出版年
2024年 | 2篇 |
2023年 | 13篇 |
2022年 | 64篇 |
2021年 | 85篇 |
2020年 | 37篇 |
2019年 | 36篇 |
2018年 | 46篇 |
2017年 | 27篇 |
2016年 | 48篇 |
2015年 | 47篇 |
2014年 | 53篇 |
2013年 | 110篇 |
2012年 | 91篇 |
2011年 | 105篇 |
2010年 | 94篇 |
2009年 | 63篇 |
2008年 | 71篇 |
2007年 | 53篇 |
2006年 | 56篇 |
2005年 | 43篇 |
2004年 | 43篇 |
2003年 | 32篇 |
2002年 | 35篇 |
2001年 | 14篇 |
2000年 | 20篇 |
1999年 | 15篇 |
1998年 | 23篇 |
1997年 | 14篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1965年 | 1篇 |
排序方式: 共有1437条查询结果,搜索用时 312 毫秒
41.
DNA barcoding as a new tool for food traceability 总被引:1,自引:0,他引:1
Andrea Galimberti Fabrizio De Mattia Alessia Losa Ilaria Bruni Silvia Federici Maurizio Casiraghi Stefano Martellos Massimo Labra 《Food research international (Ottawa, Ont.)》2013,50(1):55-63
Food safety and quality are nowadays a major concern. Any case of food alteration, especially when reported by the media, has a great impact on public opinion. There is an increasing demand for the improvement of quality controls, hence addressing scientific research towards the development of reliable molecular tools for food analysis. DNA barcoding is a widely used molecular-based system, which can identify biological specimens, and is used for the identification of both raw materials and processed food. In this review the results of several researches are critically analyzed, in order to exploit the effectiveness of DNA barcoding in food traceability, and to delineate some best practices in the application of DNA barcoding throughout the industrial pipeline. The use of DNA barcoding for food safety and in the identification of commercial fraud is also discussed. 相似文献
42.
43.
44.
45.
Debora Giordano Francesca Vanara Amedeo Reyneri Massimo Blandino 《International Journal of Food Science & Technology》2016,51(11):2468-2473
Maize germ is a by‐product of the maize milling process that is characterised by a high nutritional value. Currently, heat treatments are employed to prevent full‐fat maize germ from spoilage. The aim of this research was to study the effect of five dry‐heat treatments on the nutritional value of full‐fat maize germ. The results confirmed that after each dry‐heat treatment, the lipase activity decreases but the use of high temperatures could be detrimental for phytosterol and thiamine concentrations. The main negative effects have been observed after treatments at 140 °C for 30 min and 160 °C for 10 min. No significant difference has been observed for protein, ash or fatty acid contents. The treatment at 140 °C for 20 min resulted an optimal combination between temperature and heating time to inactivate lipase without altering deeply the nutritional value and the colour of maize germ. 相似文献
46.
Renato Colle Giuseppe Grosso Alberto Ronzani Massimo Gazzano Vincenzo Palermo 《Carbon》2012,50(3):1332-1337
We describe the self-assembly of soluble, chemically modified fullerene [6,6]-phenyl C61 butyric acid methyl ester (PCBM) into a new crystalline phase where the C60 moieties are arranged in parallel layers. Minimum C60 center-to-center distance is 10 Å within the layers, and up to 15 Å perpendicular to the layers. Highly anisotropic, mesoscopic hexagonal crystals of this material, with a lateral size of many microns and a thickness below 1 μm, are obtained from chloroform solution by solvent vapor annealing, and characterized by optical microscopy and X-ray diffraction. The crystalline structure is deduced combining experimental data with molecular modeling and ab initio calculations. The large difference in C60–C60 spacing indicates a high anisotropy in electrical and charge transport properties of this new phase. 相似文献
47.
Massimo Nespolo 《Crystallography Reviews》2017,23(4):302-303
Some statements in the review by Liu et al. [Liu Y, Liu Y, Drew GB. Comparison of calculations for interplanar distances in a crystal lattice. Cryst Rev. 2017] are corrected. The role of metric tensor to simplify calculations of interplanar spacings in crystal lattices is emphasized. 相似文献
48.
Sergio Scognamillo Emilia Gioffredi Massimo Piccinini Massimo Lazzari Valeria Alzari Daniele Nuvoli Roberta Sanna Daniele Piga Giulio Malucelli Alberto Mariani 《Polymer》2012,53(19):4019-4024
Thermoplastic polyurethane (TPU) nanocomposites containing graphene and graphene nanoribbons were obtained by polymerizing 1,4-butanediol with two diisocyanates (namely, 1,6-hexane diisocyanate or isophorone diisocyanate), in which the nanofillers were previously dispersed. Raman spectroscopy and Transmission Electron Microscopy demonstrated the formation of few-layer graphene and graphene nanoribbons dispersed in the monomers. At variance to the methods commonly reported in literature, that used in this work consists of the direct exfoliation of graphite without any chemical manipulation. Apart from the obvious cost and ease advantages, the so-obtained graphene does not contain any carboxy or alkoxy groups formed during the exfoliation process, which, at variance, are typically present in the most commonly reported methods. This finding paves the way toward the large-scale production of graphene and its nanoribbons, which are considered even more interesting than graphene itself for many potential applications. The obtained nanocomposites show a peculiar thermal and rheological behavior due to the presence of the nanofillers and to their reinforcing or plasticizing effect exerted on the TPU matrices. 相似文献
49.
50.
Lorenzo Spinelli Giovanna Tissoni Luigi A. Lugiato Massimo Brambilla 《Journal of Modern Optics》2013,60(14-15):2413-2422
We introduce here a model which includes the thermal dynamics in the time evolution of a semiconductor multiple quantum well microresonator, driven by a coherent holding beam. The active layer is electrically pumped, in order to obtain population inversion, but it is maintained below the lasing threshold. We show that the inclusion of thermal effects introduces a Hopf instability which may dominate the dynamical behaviour of the system in some operational regimes. In those cases our numerical simulations show that both spatial patterns and cavity solitons perform a drift motion in the transverse direction. This motion develops over the slow time scale which characterizes thermal effects. 相似文献