全文获取类型
收费全文 | 1867篇 |
免费 | 190篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 39篇 |
综合类 | 11篇 |
化学工业 | 474篇 |
金属工艺 | 58篇 |
机械仪表 | 32篇 |
建筑科学 | 152篇 |
矿业工程 | 2篇 |
能源动力 | 51篇 |
轻工业 | 72篇 |
水利工程 | 6篇 |
无线电 | 190篇 |
一般工业技术 | 413篇 |
冶金工业 | 108篇 |
原子能技术 | 9篇 |
自动化技术 | 446篇 |
出版年
2024年 | 6篇 |
2023年 | 52篇 |
2022年 | 64篇 |
2021年 | 102篇 |
2020年 | 86篇 |
2019年 | 79篇 |
2018年 | 85篇 |
2017年 | 71篇 |
2016年 | 99篇 |
2015年 | 99篇 |
2014年 | 117篇 |
2013年 | 135篇 |
2012年 | 146篇 |
2011年 | 160篇 |
2010年 | 136篇 |
2009年 | 93篇 |
2008年 | 99篇 |
2007年 | 88篇 |
2006年 | 75篇 |
2005年 | 50篇 |
2004年 | 29篇 |
2003年 | 14篇 |
2002年 | 19篇 |
2001年 | 16篇 |
2000年 | 8篇 |
1999年 | 12篇 |
1998年 | 25篇 |
1997年 | 19篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 7篇 |
1993年 | 4篇 |
1991年 | 4篇 |
1989年 | 2篇 |
1986年 | 5篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1975年 | 4篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1968年 | 1篇 |
1966年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有2063条查询结果,搜索用时 0 毫秒
71.
The processing of manganese nodules for the production of raw materials has been a subject of research for many decades. The nodules contain many valuable metals like copper, cobalt and nickel. In recent years, the German Federal Institute for Geoscience and Natural Resources developed a process for the processing of manganese nodules based on a combined pyro- and a hydrometallurgical route. Clausthal University of Technology was assigned to develop the hydrometallurgical process for the treatment of a FeNiCuCo alloy. The developed process consists of pressurized sulfuric acid leaching with the suppression of hydrogen gas formation, precipitation and solvent extraction. 相似文献
72.
Combining Acoustic Emission and Vibration Technologies Harbors Huge Potential for Material Characterization 下载免费PDF全文
Karl Nienhaus Hermann Wotruba Domenic Boos Simon Klösges Tobias Vraetz Kilian Neubert 《化学工程与技术》2015,38(12):2253-2260
The demand for raw materials is growing worldwide, in step with increasing world population and rising living standards of emerging countries. It is becoming more difficult to exploit primary raw materials because of declining ore grades and increasingly complicated mineralogies. Thus, the efficient and environmentally sustainable exploitation of primary resources using innovative technologies has emerged as an important research field to address these issues. An innovative approach is introduced to optimize process and quality control by combining acoustic emission (AE) and vibration technology. The general feasibility of these two technologies for material recognition and characterization is examined. The new approach was tested to determine whether coal could be distinguished from waste rock. 相似文献
73.
Nonspherical drops are of interest in the formation of microcapsules in life sciences like food, pharmacy, and cosmetics, agro and fine chemicals as well as material sciences. Out of many systems, particle‐stabilized emulsion drops, so‐called Pickering emulsions, exhibit an interesting formulation. Systems with Pickering particles applied in an excess amount were investigated. During deformation, the particles fully covered the enlarged drop interfaces and prevented its relaxation to a spherical drop shape. Nonspherical drops could be produced in simple shear flow using an adequate process routine. The production in a simple device is a promising high‐throughput alternative to microfluidic devices. 相似文献
74.
Stability of rare‐earth‐doped spherical yttria‐stabilized zirconia synthesized by ultrasonic spray pyrolysis 下载免费PDF全文
Nazia Nafsin Hui Li Elisabeth W. Leib Tobias Vossmeyer Pieter Stroeve Ricardo H. R. Castro 《Journal of the American Ceramic Society》2017,100(10):4425-4434
Phase stability is one of the crucial requirements for any material that can be used at elevated temperature applications such as thermal barrier coating (TBC). The most traditional TBC material, partially stabilized zirconia, limits the operating temperature due to its phase transformation. Conversely, the low thermal conductivity of fully stabilized zirconia (YSZ) may enable effective reduction in the surface temperature on the coated component, while avoiding deleterious phase transitions, although still being subjected to sintering and grain growth. It has been reported that addition of rare‐earths as dopants to YSZ can significantly increase resistance to grain growth at high temperature. Keeping this under consideration, this work investigates the role of rare‐earths (lanthanum and gadolinium) in increasing thermal stability of YSZ microspheres, the building blocks for high‐temperature photonics for reflective TBC. The spheres were produced by ultrasonic spray pyrolysis, and the doping led to significant improvement of stability by significant inhibition of grain growth. While the individual dopants showed significant growth and sintering inhibition up to 900°C, co‐doping with 4% (in mol) of each (Gd and La) led to coarsening resistance up to 1000°C for 3 hours, when particles retained reasonable spherical features with nanometric crystallite sizes. 相似文献
75.
Hierarchically Structured Poly(alkyl‐p‐xylylene) Nonwovens with Superhydrophobic Properties 下载免费PDF全文
Hierarchically structured poly(alkyl‐p‐xylylene) (alkyl‐PPX) nonwovens are prepared by specific parameter variation during the electrospinning process. The investigated parameters are changes in solutions properties and ambient humidity level, which lead to the formation of different fiber architectures and surface morphologies. The characterization of the nonwovens by scanning electron microscopy confirms the formation of hierarchically structured fibers, comprising bead‐on‐string architecture if spun from tetrahydrofuran (THF) solutions, and porous surfaces at relative humidity (RH) levels > 30% for both chloroform and THF solutions. The wetting properties of nonwovens spun from THF and chloroform solutions are analyzed by water contact angle (CA) measurements, roll‐angle determination, and high speed imaging. PPX‐heptyl and PPX‐butyl fiber mats spun from 2.5 wt% THF and PPX‐heptyl spun from 3 wt% chloroform solutions at RH > 75% show superhydrophobic and self‐cleaning properties with CA > 153° and roll‐off angles of 10–15°. The nonwovens maintain their fiber morphology and water‐repellent properties after thermal and mechanical stress.
76.
Surface Binding of TOTAPOL Assists Structural Investigations of Amyloid Fibrils by Dynamic Nuclear Polarization NMR Spectroscopy 下载免费PDF全文
Dr. Madhu Nagaraj Dr. Trent W. Franks Siavash Saeidpour Dr. Tobias Schubeis Dr. Hartmut Oschkinat Dr. Christiane Ritter Dr. Barth‐Jan van Rossum 《Chembiochem : a European journal of chemical biology》2016,17(14):1308-1311
Dynamic nuclear polarization (DNP) NMR can enhance sensitivity but often comes at the price of a substantial loss of resolution. Two major factors affect spectral quality: low‐temperature heterogeneous line broadening and paramagnetic relaxation enhancement (PRE) effects. Investigations by NMR spectroscopy, isothermal titration calorimetry (ITC), and EPR revealed a new substantial affinity of TOTAPOL to amyloid surfaces, very similar to that shown by the fluorescent dye thioflavin‐T (ThT). As a consequence, DNP spectra with remarkably good resolution and still reasonable enhancement could be obtained at very low TOTAPOL concentrations, typically 400 times lower than commonly employed. These spectra yielded several long‐range constraints that were difficult to obtain without DNP. Our findings open up new strategies for structural studies with DNP NMR spectroscopy on amyloids that can bind the biradical with affinity similar to that shown towards ThT. 相似文献
77.
A Catalytic Nanoreactor Based on in Vivo Encapsulation of Multiple Enzymes in an Engineered Protein Nanocompartment 下载免费PDF全文
Dr. Tobias W. Giessen Prof. Dr. Pamela A. Silver 《Chembiochem : a European journal of chemical biology》2016,17(20):1931-1935
Bacterial protein compartments concentrate and sequester enzymes, thereby regulating biochemical reactions. Here, we generated a new functional nanocompartment in Escherichia coli by engineering the MS2 phage capsid protein to encapsulate multiple cargo proteins. Sequestration of multiple proteins in MS2‐based capsids was achieved by SpyTag/SpyCatcher protein fusions that covalently crosslinked with the interior surface of the capsid. Further, the functional two‐enzyme indigo biosynthetic pathway could be targeted to the engineered capsids, leading to a 60 % increase in indigo production in vivo. The enzyme‐loaded particles could be purified in their active form and showed enhanced long‐term stability in vitro (about 95 % activity after seven days) compared with free enzymes (about 5 % activity after seven days). In summary, this engineered in vivo encapsulation system provides a simple and versatile way for generating highly stable multi‐enzyme nanoreactors for in vivo and in vitro applications. 相似文献
78.
Andreas M. Kern Bodo Zierath Joachim Haertlé Tobias Fey Bastian J. M. Etzold 《化学工程与技术》2016,39(6):1121-1129
The influence of graphitization and composition of carbide‐derived carbon (CDC) monoliths on the electrical and thermal conductivity was investigated. Carbon monoliths with varying porosities were synthesized employing biomorphous macroporous TiC and SiC as precursors. Graphitization was carried out in situ during high‐temperature chlorination with and without addition of nickel, iron, and cobalt chloride to the carbide. The graphitized monoliths showed improved properties. The results demonstrate that despite graphitic carbon also glass‐like carbon, stemming from the carbide synthesis, increases the thermal and electrical conductivity significantly. 相似文献
79.
Björn Schulz Tobias Meinert David Bierbüsse Michel Busen Nina Körtzinger Michael Stankowski Gunnar Seide 《化学,工程师,技术》2016,88(10):1501-1507
Aerogels are high‐performance materials used for space and aviation purposes. Cellulose aerogel fibers have been investigated under real space conditions for their insulation properties. The experiments were carried out in a one‐stage high‐altitude research rocket of the improved ORION type. A cuboid module with measurement cells, camera modules, and electronic devices has been developed for monitoring the insulation behavior of cellulose aerogel non‐woven samples. The thermal behavior of these samples has been analyzed and compared to cellulose cloth (cotton) and aluminum for reference. 相似文献
80.
Post‐polymerization modification of bio‐based polymers: maximizing the high functionality of polymers derived from biomass 下载免费PDF全文
Thomas J Farmer James W Comerford Alessandro Pellis Tobias Robert 《Polymer International》2018,67(7):775-789
The renaissance of the bio‐based chemical industry over the last 20 years has seen an ever growing interest in the synthesis of new bio‐based polymers. The building blocks of these new polymers, so called platform molecules, contain significantly more chemical functionality than their petrochemical counterparts (such as ethene, propene and para‐xylene). As a result bio‐based polymers often contain greater residual chemical functionality in their chains, with groups such as alkenes and hydroxyls commonly observed. These functional groups can act as sites for post‐polymerization modification (PPM), thus further extending the range of applications for bio‐based polymers by tailoring the polymers' final properties. This mini‐review highlights some of the most recent and compelling examples of how to make use of bio‐based polymers with residual functional groups for PPM. It also looks at how the emerging interdisciplinary field of enzymatic polymer synthesis allows for increased functionality in polymers by avoiding side‐reactions as a result of milder reaction conditions, and additionally offers an alternative means of polymer surface modification. © 2018 Society of Chemical Industry 相似文献