全文获取类型
收费全文 | 2397篇 |
免费 | 114篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 16篇 |
综合类 | 5篇 |
化学工业 | 505篇 |
金属工艺 | 40篇 |
机械仪表 | 53篇 |
建筑科学 | 218篇 |
矿业工程 | 1篇 |
能源动力 | 114篇 |
轻工业 | 267篇 |
水利工程 | 40篇 |
石油天然气 | 7篇 |
无线电 | 148篇 |
一般工业技术 | 444篇 |
冶金工业 | 161篇 |
原子能技术 | 20篇 |
自动化技术 | 473篇 |
出版年
2023年 | 26篇 |
2022年 | 16篇 |
2021年 | 55篇 |
2020年 | 44篇 |
2019年 | 52篇 |
2018年 | 64篇 |
2017年 | 56篇 |
2016年 | 67篇 |
2015年 | 62篇 |
2014年 | 90篇 |
2013年 | 172篇 |
2012年 | 145篇 |
2011年 | 163篇 |
2010年 | 141篇 |
2009年 | 119篇 |
2008年 | 145篇 |
2007年 | 127篇 |
2006年 | 115篇 |
2005年 | 108篇 |
2004年 | 94篇 |
2003年 | 73篇 |
2002年 | 79篇 |
2001年 | 34篇 |
2000年 | 32篇 |
1999年 | 35篇 |
1998年 | 44篇 |
1997年 | 29篇 |
1996年 | 27篇 |
1995年 | 21篇 |
1994年 | 24篇 |
1993年 | 25篇 |
1992年 | 15篇 |
1991年 | 10篇 |
1990年 | 12篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 10篇 |
1985年 | 8篇 |
1984年 | 9篇 |
1983年 | 6篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 7篇 |
1978年 | 7篇 |
1943年 | 16篇 |
1942年 | 12篇 |
1941年 | 8篇 |
1940年 | 8篇 |
1939年 | 7篇 |
1937年 | 5篇 |
排序方式: 共有2512条查询结果,搜索用时 15 毫秒
91.
Lars Mouwitz 《AI & Society》2013,28(1):75-76
The background to the “Poem for an Empty Spot” is a creepy feeling that there is something questionable with the motive and deeper driving forces for the efforts to declare that mind is something else than it is. As a scientist using mathematics I have learned the importance to take deep feelings seriously, and not only trust on deduction and routine solutions. Our deep feelings serve as pathfinders, and as pre-paradigmatic signs they are important to notice. 相似文献
92.
Christian Immanuel Müller Thomas Rauscher Andreas Schmidt Thomas Schubert Thomas Weißgärber Bernd Kieback Lars Röntzsch 《International Journal of Hydrogen Energy》2014
In this work different amorphous melt-spun Fe-alloys (Fe82B18, Fe80Si10B10, Fe60Co20Si10B10) were investigated as cathode materials for the alkaline electrolysis of water. In particular, the influence of cobalt as well as the metalloids boron and silicon on the activity for the hydrogen evolution reaction (HER) was studied in 1 M KOH at 298 K using cyclic voltammetric, galvanostatic and polarization techniques. The electrocatalytic activity was evaluated in the view of the overpotential. It was found that cyclic voltammetric techniques can be used to activate the melt-spun Fe-alloys strongly. Different cyclic voltammetric activation procedures are discussed and the influence of the sweep rate and the potential window on the HER activity was elucidated. The experimental data indicate that the addition of metalloids and, most importantly, of cobalt improves the HER activity of the materials. Thus, the overpotential can be reduced by 200 mV compared to polycrystalline Ni. 相似文献
93.
94.
Rajiv K. Bedi Dr. Danzhi Huang Stefanie A. Eberle Dr. Lars Wiedmer Dr. Pawel Śledź Prof. Amedeo Caflisch 《ChemMedChem》2020,15(9):744-748
The RNA methylase METTL3 catalyzes the transfer of a methyl group from the cofactor S-adenosyl-L-methionine (SAM) to the N6 atom of adenine. We have screened a library of 4000 analogues and derivatives of the adenosine moiety of SAM by high-throughput docking into METTL3. Two series of adenine derivatives were identified in silico, and the binding mode of six of the predicted inhibitors was validated by protein crystallography. Two compounds, one for each series, show good ligand efficiency. We propose a route for their further development into potent and selective inhibitors of METTL3. 相似文献
95.
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
96.
97.
Previous attempts to use polylactide (PLA) latex particles and nanofibrillated cellulose (NFC) in papermaking processing have been limited to low NFC content. In the present study, a bionanocomposite material was successfully produced using a PLA latex and NFC. The components were mixed using a wet mixing method and bionanocomposite films were made by filtration followed by hot pressing. In composite materials, the dispersion of the reinforcing component in the matrix is critical for the material properties. Biopolymers such as PLA are non-polar and soluble only in organic solvents; NFC is, however, highly hydrophilic. By utilizing latex, i.e., an aqueous dispersion of biopolymer micro-particles, wet mixing is possible and the problem of aggregation of the hydrophilic nanocellulose in organic solvent is avoided. The properties of the resulting NFC/PLA latex bionanocomposite films were analyzed. Thorough blending resulted in good dispersion of the reinforcing component within the matrix. Adding increasing amounts of NFC improved the Young's modulus, tensile strength, and strain at break of the bionanocomposite material. The increase in the tensile properties was linear with increasing NFC content as a result of the good dispersion. The NFC also improved the thermal stability of the bionanocomposite material. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
98.
Prof. Dr. Andreas Fink Prof. Dr. Natalia Kliewer Prof. Dr. Dirk Mattfeld Prof. Dr. Lars Mönch Prof. Dr. Franz Rothlauf Prof. Dr. Guido Schryen Prof. Dr. Leena Suhl Prof. Dr. Stefan Voß 《WIRTSCHAFTSINFORMATIK》2014,56(1):21-29
In this paper, we sketch some of the challenges that should be addressed in future research efforts for model-based decision support in manufacturing and service networks. This includes integration issues, taking into account the autonomy of the decision-making entities in face of information asymmetry, the modeling of preferences of the decision-makers, efficiently determining robust solutions, i.e. solutions that are insensitive with respect to changes in the problem data, and a reduction of the time needed for model building and usage. The problem solution cycle includes problem analysis, the design of appropriate algorithms and their performance assessment. We are interested in a prototypical integration of the proposed methods within application systems, which can be followed up with field tests of the extended application systems. We argue that the described research agenda requires the interdisciplinary collaboration of business and information systems engineering researchers with colleagues from management science, computer science, and operations research. In addition, we present some exemplifying, illustrative examples of relevant research results. 相似文献
99.
An integral equation method for solving the eddy-current nondestructive evaluation problem of a flat, rectangular, near surface crack inside of a cylindrical hole in a conducting material is presented. The method involves expanding the Green’s tensor, the incoming field, and the jump in electric potential over the crack in suitable basis functions. Here, plane waves, cylindrical waves, and basis functions related to the Chebyshev polynomials, are used. The way of discretization in this method leads to a formulation where the scattering is defined by a scattering matrix, independent of the incoming field. This presents an advantage, when conducting numerical simulations, since the scattering matrix does not have to be recalculated for every probe position. The numerical calculations are straightforward to perform and model predictions are compared with finite element results. 相似文献
100.
Stefanie Dietmair Lars K. Nielsen Nicholas E. Timmins 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(7):905-914
Mammalian cells are the preferred host for the manufacture of a wide range of biopharmaceuticals, but production costs are high owing to low productivity. A range of rational engineering strategies have been pursued in order to increase volumetric product titres from mammalian cells, such as delaying apoptosis, manipulation of the cell cycle, and improving metabolism and protein processing. Unfortunately, outcomes from these strategies have been mixed, with few instances where significant improvements in product yield have been achieved. This article reviews and contrasts many of the engineering strategies attempted to date, highlighting the variability and context specificity in outcome. The paper argues that this is a reflection of the complexity of mammalian cells, and that a deeper understanding of the biology underpinning protein production for biotechnological purposes is required. Copyright © 2011 Society of Chemical Industry 相似文献