全文获取类型
收费全文 | 680篇 |
免费 | 39篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 263篇 |
金属工艺 | 9篇 |
机械仪表 | 13篇 |
建筑科学 | 15篇 |
能源动力 | 28篇 |
轻工业 | 83篇 |
水利工程 | 3篇 |
石油天然气 | 4篇 |
无线电 | 57篇 |
一般工业技术 | 93篇 |
冶金工业 | 17篇 |
原子能技术 | 3篇 |
自动化技术 | 127篇 |
出版年
2023年 | 6篇 |
2022年 | 24篇 |
2021年 | 58篇 |
2020年 | 30篇 |
2019年 | 25篇 |
2018年 | 27篇 |
2017年 | 21篇 |
2016年 | 36篇 |
2015年 | 22篇 |
2014年 | 39篇 |
2013年 | 47篇 |
2012年 | 49篇 |
2011年 | 42篇 |
2010年 | 38篇 |
2009年 | 36篇 |
2008年 | 25篇 |
2007年 | 25篇 |
2006年 | 18篇 |
2005年 | 15篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1987年 | 5篇 |
1986年 | 2篇 |
1985年 | 7篇 |
1984年 | 4篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1971年 | 3篇 |
1961年 | 1篇 |
1959年 | 1篇 |
1939年 | 1篇 |
1937年 | 1篇 |
1933年 | 2篇 |
1916年 | 2篇 |
排序方式: 共有719条查询结果,搜索用时 46 毫秒
661.
Pedro Couto Aranzazu Jurio Artur Varej?o Miguel Pagola Humberto Bustince Pedro Melo-Pinto 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2011,15(10):1937-1944
In this work, image segmentation is addressed as the starting point within a motion analysis methodology intended for rat
biomechanics behavior characterization. First, we propose a general segmentation framework that uses interval valued fuzzy
sets (IVFSs) to determine the optimal image threshold value. The amplitude values of the IVFSs are used for representing the
unknowledge/ignorance of an expert on determining whether a pixel belongs to the background or to the object of the image.
Then, we introduce an extension of this methodology that uses a heuristic-based multi-threshold approach to determine the
optimal threshold. Experimental results are presented. 相似文献
662.
Lugmayr Artur Sutinen Erkki Suhonen Jarkko Sedano Carolina Islas Hlavacs Helmut Montero Calkin Suero 《Multimedia Tools and Applications》2017,76(14):15707-15733
Multimedia Tools and Applications - In human culture, storytelling is a long-established tradition. The reasons people tell stories are manifold: to entertain, to transfer knowledge between... 相似文献
663.
Light‐Induced Contraction/Expansion of 1D Photoswitchable Metallopolymer Monitored at the Solid–Liquid Interface
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Mohamed El Garah Etienne Borré Artur Ciesielski Arezoo Dianat Rafael Gutierrez Gianaurelio Cuniberti Stéphane Bellemin‐Laponnaz Matteo Mauro Paolo Samorì 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(40)
The use of a bottom‐up approach to the fabrication of nanopatterned functional surfaces, which are capable to respond to external stimuli, is of great current interest. Herein, the preparation of light‐responsive, linear supramolecular metallopolymers constituted by the ideally infinite repetition of a ditopic ligand bearing an azoaryl moiety and Co(II) coordination nodes is described. The supramolecular polymerization process is followed by optical spectroscopy in dimethylformamide solution. Noteworthy, a submolecularly resolved scanning tunneling microscopy (STM) study of the in situ reversible trans‐to‐cis photoisomerization of a photoswitchable metallopolymer that self‐assembles into 2D crystalline patterns onto a highly oriented pyrolytic graphite surface is achieved for the first time. The STM analysis of the nanopatterned surfaces is corroborated by modeling the physisorbed species onto a graphene slab before and after irradiation by means of density functional theory calculation. Significantly, switching of the monolayers consisting of supramolecular Co(II) metallopolymer bearing trans‐azoaryl units to a novel pattern based on cis isomers can be triggered by UV light and reversed back to the trans conformer by using visible light, thereby restoring the trans‐based supramolecular 2D packing. These findings represent a step forward toward the design and preparation of photoresponsive “smart” surfaces organized with an atomic precision. 相似文献
664.
Juanmei Duan Phanish Chava Mahdi Ghorbani-Asl Denise Erb Liang Hu Arkady V. Krasheninnikov Harald Schneider Lars Rebohle Artur Erbe Manfred Helm Yu-Jia Zeng Shengqiang Zhou Slawomir Prucnal 《Advanced functional materials》2021,31(40):2104960
Trions, quasi-particles consisting of two electrons combined with one hole or of two holes with one electron, have recently been observed in transition metal dichalcogenides (TMDCs) and drawn increasing attention due to potential applications of these materials in light-emitting diodes, valleytronic devices as well as for being a testbed for understanding many-body phenomena. Therefore, it is important to enhance the trion emission and its stability. In this study, a MoSe2/FePS3 van der Waals heterostructure (vdWH) with type-I band alignment is constructed, which allows for carriers injection from FePS3 to MoSe2. At low temperatures, the neutral exciton (X0) emission in this vdWH is almost completely suppressed. The ITrion/Ix0 intensity ratio increases from 0.44 in a single MoSe2 monolayer to 20 in this heterostructure with the trion charging state changing from negative in the monolayer to positive in the heterostructure. The optical pumping with circularly polarized light shows a 14% polarization for the trion emission in MoSe2/FePS3. Moreover, forming such type-I vdWH also gives rise to a 20-fold enhancement of the room temperature photoluminescence from monolayer MoSe2. These results demonstrate a novel approach to convert excitons to trions in monolayer 2D TMDCs via interlayer doping effect using type-I band alignment in vdWH. 相似文献
665.
Dawid Pakulski Wodzimierz Czepa Stefano Del Buffa Artur Ciesielski Paolo Samorì 《Advanced functional materials》2020,30(2)
Membrane‐based processes, namely, water purification and harvesting of osmotic power deriving from the difference in salinity between seawater and freshwater are two strategic research fields holding great promise for overcoming critical global issues such as the world growing energy demand, climate change, and access to clean water. Ultrathin membranes based on 2D materials (2DMs) are particularly suitable for highly selective separation of ions and effective generation of blue energy because of their unique physicochemical properties and novel transport mechanisms occurring at the nano‐ and sub‐nanometer length scale. However, due to the relatively high costs of fabrication compared to traditional porous membrane materials, their technological transfer toward large‐scale applications still remains a great challenge. Herein, the authors present an overview of the current state‐of‐the‐art in the development of ultrathin membranes based on 2DMs for osmotic power generation and water purification. The authors discuss several synthetic routes to produce atomically thin membranes with controlled porosity and describe in detail their performance, with a particular emphasis on pressure‐retarded osmosis and reversed electrodialysis methods. In the last section, an outlook and current limitations as well as viable future developments in the field of 2DM membranes are provided. 相似文献
666.
Małgorzata Karpińska-Krakowiak Artur Modliński 《Journal of Computer Information Systems》2018,58(3):282-290
Practical jokes belong to the category of disparagement humor and they have been extensively investigated by social scientists for decades. Nevertheless, the available empirical results pertain mostly to human-to-human situations and little is known on the effects of pranks in the computer-mediated environment (CME). As CME encourages different patterns of reactions and behaviors than non-CME, the present study provides an experimental evaluation of consumer responses to brands that use practical jokes in their social media communication. The results reveal that high-disparagement pranks may significantly hurt brand perceptions and decrease brand affect. This effect is better predicted by prior brand attitudes than usage (i.e., the more favorable predisposition to a brand, the higher probability that a high-disparagement prank will produce a lower brand affect). No significant impact of low-disparagement pranks was found on subsequent brand responses. The findings will help scholars and practitioners in understanding this new phenomenon and in maximizing returns from humor online. 相似文献
667.
668.
Artur Medvid' Natalia Litovchenko Aleksandr Mychko Yuriy Naseka 《Nanoscale research letters》2012,7(1):514
The investigation of surface morphology using atomic force microscope has shown self-organizing of the nanocones on the surface of CdZnTe crystal after irradiation by strongly absorbed Nd:YAG laser irradiation at an intensity of 12.0 MW/cm2. The formation of nanocones is explained by the presence of a thermogradient effect in the semiconductor. The appearance of a new exciton band has been observed after irradiation by the laser which is explained by the exciton quantum confinement effect in nanocones. 相似文献
669.
Artur Campos Dália Maia Stefan D?tterl Roman Kaiser Ilse Silberbauer-Gottsberger Holger Teichert Marc Gibernau Daniela Maria do Amaral Ferraz Navarro Clemens Schlindwein Gerhard Gottsberger 《Journal of chemical ecology》2012,38(9):1072-1080
Cyclocephaline scarabs are specialised scent-driven pollinators, implicated with the reproductive success of several Neotropical plant taxa. Night-blooming flowers pollinated by these beetles are thermogenic and release intense fragrances synchronized to pollinator activity. However, data on floral scent composition within such mutualistic interactions are scarce, and the identity of behaviorally active compounds involved is largely unknown. We performed GC-MS analyses of floral scents of four species of Annona (magnoliids, Annonaceae) and Caladium bicolor (monocots, Araceae), and demonstrated the chemical basis for the attraction of their effective pollinators. 4-Methyl-5-vinylthiazole, a nitrogen and sulphur-containing heterocyclic compound previously unreported in flowers, was found as a prominent constituent in all studied species. Field biotests confirmed that it is highly attractive to both male and female beetles of three species of the genus Cyclocephala, pollinators of the studied plant taxa. The origin of 4-methyl-5-vinylthiazole in plants might be associated with the metabolism of thiamine (vitamin B1), and we hypothesize that the presence of this compound in unrelated lineages of angiosperms is either linked to selective expression of a plesiomorphic biosynthetic pathway or to parallel evolution. 相似文献
670.
Artur Seweryn Tomasz Wasilewski Anita Bocho-Janiszewska 《International journal of molecular sciences》2021,22(12)
The article shows that the type and concentration of inorganic salt can be translated into the structure of the bulk phase and the performance properties of ecological all-purpose cleaners (APC). A base APC formulation was developed. Thereafter, two types of salt (sodium chloride and magnesium chloride) were added at various concentrations to obtain different structures in the bulk phase. The salt addition resulted in the formation of spherical micelles and—upon addition of more electrolyte—of aggregates having a lamellar structure. The formulations had constant viscosities (ab. 500 mPa·s), comparable to those of commercial products. Essential physical-chemical and performance properties of the four formulations varying in salt types and concentrations were evaluated. It was found that the addition of magnesium salt resulted in more favorable characteristics due to the surface activity of the formulations, which translated into adequately high wettability of the investigated hydrophobic surfaces, and their ability to emulsify fat. A decreasing relationship was observed in foaming properties: higher salt concentrations lead to worse foaming properties and foam stability of the solutions. For the magnesium chloride composition, the effect was significantly more pronounced, as compared to the sodium chloride-based formulations. As far as safety of use is concerned, the formulations in which magnesium salt was used caused a much lesser irritation compared with the other investigated formulations. The zein value was observed to decrease with increasing concentrations of the given type of salt in the composition. 相似文献