全文获取类型
收费全文 | 1109篇 |
免费 | 39篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 4篇 |
综合类 | 9篇 |
化学工业 | 368篇 |
金属工艺 | 36篇 |
机械仪表 | 17篇 |
建筑科学 | 54篇 |
矿业工程 | 3篇 |
能源动力 | 19篇 |
轻工业 | 95篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 66篇 |
一般工业技术 | 236篇 |
冶金工业 | 107篇 |
原子能技术 | 8篇 |
自动化技术 | 123篇 |
出版年
2023年 | 9篇 |
2022年 | 17篇 |
2021年 | 29篇 |
2020年 | 20篇 |
2019年 | 32篇 |
2018年 | 22篇 |
2017年 | 19篇 |
2016年 | 28篇 |
2015年 | 24篇 |
2014年 | 30篇 |
2013年 | 59篇 |
2012年 | 56篇 |
2011年 | 74篇 |
2010年 | 49篇 |
2009年 | 50篇 |
2008年 | 50篇 |
2007年 | 42篇 |
2006年 | 37篇 |
2005年 | 36篇 |
2004年 | 34篇 |
2003年 | 23篇 |
2002年 | 22篇 |
2001年 | 29篇 |
2000年 | 27篇 |
1999年 | 25篇 |
1998年 | 33篇 |
1997年 | 23篇 |
1996年 | 21篇 |
1995年 | 20篇 |
1994年 | 12篇 |
1993年 | 16篇 |
1992年 | 13篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 10篇 |
1988年 | 17篇 |
1987年 | 12篇 |
1985年 | 10篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 13篇 |
1980年 | 6篇 |
1979年 | 4篇 |
1976年 | 8篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 4篇 |
1972年 | 8篇 |
1971年 | 4篇 |
1970年 | 6篇 |
排序方式: 共有1149条查询结果,搜索用时 31 毫秒
101.
Achim Streit Piotr Bala Alexander Beck-Ratzka Krzysztof Benedyczak Sandra Bergmann Rebecca Breu Jason Milad Daivandy Bastian Demuth Anastasia Eifer André Giesler Björn Hagemeier Sonja Holl Valentina Huber Nadine Lamla Daniel Mallmann Ahmed Shiraz Memon Mohammad Shahbaz Memon Michael Rambadt Morris Riedel Mathilde Romberg Bernd Schuller Tobias Schlauch Andreas Schreiber Thomas Soddemann Wolfgang Ziegler 《电信纪事》2010,65(11-12):757-762
UNICORE is a European Grid Technology with more than 10 years of history. Originating from the Supercomputing domain, the latest version UNICORE 6 has turned into a general-purpose Grid technology that follows established standards and offers a rich set of features to its users. The paper starts with an architectural insight into UNICORE 6, highlighting the workflow features, standards and the different clients. Next, the current state of advancement is presented by describing recent developments. The paper closes with an outlook on future planned developments. 相似文献
102.
Emanuel Ionescu Benjamin Papendorf Hans-Joachim Kleebe Hergen Breitzke Katharina Nonnenmacher Gerd Buntkowsky Ralf Riedel 《Journal of the European Ceramic Society》2012,32(9):1873-1881
The polymer-to-ceramic transformation of a hafnium alkoxide-modified polysilazane was investigated via thermogravimetric analysis coupled with in situ mass spectrometry (TG/MS), nuclear magnetic resonance (MAS NMR) and transmission electron microscopy (TEM). The results indicate that the structural evolution of the polysilazane upon ceramization is strongly affected by the modification with hafnium alkoxide. Thus, the content of carbon in the ceramic backbone was relatively low, whereas a large amount of SiN4 sites and a segregated carbon phase was present in the sample. Furthermore, this study revealed the formation of a SiHfCNO amorphous single phase ceramic via pyrolysis of the polymer at 700 °C, whereas at higher pyrolysis temperatures precipitation of hafnia was observed, leading to an amorphous hafnia/silicon carbonitride ceramic nanocomposite. The precipitation of hafnia was shown to not rely on decomposition processes, but to be a result of rearrangement reactions occurring within the ceramic material. 相似文献
103.
104.
Suelen Barg Elisângela Guzi de Moraes Dietmar Koch Georg Grathwohl 《Journal of the European Ceramic Society》2009,29(12):2439-2446
Open porous mechanically stable ceramic foams are developed by a simple direct foaming process. The new processing route is based on the transition of a surfactant stabilized highly concentrated alkane phase homogeneously distributed in a stabilized aqueous ceramic powder suspension into high performance ceramic foams with porosities up to 90% and cell sizes ranging from 3 to 200 μm. The droplet size distribution of the high alkane phase emulsified suspensions (HAPES) is efficiently controlled by the stirring velocity during emulsification experimentally investigated for varying powder particle contents. Stable foams with tailored structural features can be prepared by adjusting the rheological characteristics of HAPES being dependent on the system and process parameters. The influence of the emulsification stirring velocity on the resulting HAPES droplet size is analysed on the basis of the Taylor model of mechanical shearing describing the stresses responsible for the fragmentation of the droplets. 相似文献
105.
Mateus Carlesso Renan Giacomelli Stefan Günther Dietmar Koch Stephen Kroll Stefan Odenbach Kurosch Rezwan 《Journal of the American Ceramic Society》2013,96(3):710-718
We present an interesting processing route for obtaining alumina/mullite‐based ceramics with controlled porosity and airflow resistance leading to promising microstructures for application as sound absorbers. The use of ceramic materials aims for potential applications where high temperatures or corrosive atmospheres are predominant, e.g., in combustion chambers of gas turbines. For the production of the porous ceramics we combined freeze gelation and sacrificial templating processes to produce near‐net‐shaped parts with low shrinkage (<3%) based on environmental‐friendly and low cost conditions. The obtained microstructure presents a bimodal pore size distribution, with small pores derived from the freeze gelation process (~30 μm) connecting large pores (2–5 mm diameter) originated from the expanded polystyrene template particles. These connections, called “windows” in this study, show a significant impact on the sound absorption properties, allowing the pressure diffusion effect to take place, resulting in a significant improvement of the sound absorption coefficient. By varying the template particle content and the slurry solid content, it is possible to control the sound absorption behavior at different frequencies of the open‐celled ceramics. These ceramics feature a high open porosity, from 77% to 82%, combined with sufficient compressive strength ranging from 0.27 to 0.68 MPa and sound absorption coefficients of 0.30–0.99, representing a highly promising combination of properties for noise control and reduction at corrosive environments and high temperatures. 相似文献
106.
Reconfigurable handling system 总被引:1,自引:0,他引:1
Rainer M��ller Martin Esser Markus Jan?en Matthias Vette Burkhard Corves Mathias H��sing Martin Riedel 《Production Engineering》2011,5(4):453-461
The demand for more versatile assembly and handling systems to facilitate customized production is gaining in importance,
especially with regard to the constantly-increasing cost pressure, to expansion of the range of product versions and the shortening
of innovation cycles. As a cost-effective approach for frequently changing assembly tasks, a novel manipulation concept has
been developed by combining given robot technologies. This new handling system has a modular and adaptable layout, which consists
of several mobile arms to manipulate the object in six-dimensional Cartesian space. After grasping, when the arms are attached
to the object, the mechanical architecture is similar to parallel manipulators or cooperating robots. As the mounting and
gripping points of the arms can easily be changed, the manipulator can be reconfigured so as to match the user’s preferences
and needs. In addition to the kinematic adaption the regarding task, the hardware and new functions can be reconfigured as
well. Contact elements, measurement and assembly devices as well as testing modules can easily be in integrated in the concept.
A modular automatic control concept combined with a self-optimizing planning tool helps the user to find the optimal configuration
and realize it in an economic way. 相似文献
107.
Magdalena Graczyk-Zajac Gabriela Mera Jan Kaspar Ralf Riedel 《Journal of the European Ceramic Society》2010,30(15):3235-3243
The electrochemical behavior of poly(phenylvinylsilylcarbodiimide)-derived SiCN ceramics as anode material for lithium-ion batteries is reported here for the first time. The novel carbon-rich silicon carbonitride (SiCN) ceramics have been synthesized by the thermal treatment of poly(phenylvinylsilylcarbodiimide) under argon atmosphere at five temperatures, namely 1100, 1300, 1500, 1700 and 2000 °C. The SiCN electrodes were prepared without any conducting additives and were tested in electrochemical two electrodes cell using cyclic voltammetry and galvanostatic techniques. The capacity of the carbon-rich SiCN samples was found to be stable upon galvanostatic cycling and reaches almost 300 mAh/g for the sample prepared at 1300 °C with oxygen as the impurity. The dependence of the microstructure, especially of the crystallinity of the segregated carbon phase and of the oxygen impurities on the electrochemical behavior of the SiCN material, was analysed. At all temperatures of thermolysis, the free carbon phase has been identified as “soft carbon”. 相似文献
108.
109.
Christoph Konetschny Dusan Galusek Stefan Reschke Claudia Fasel Ralf Riedel 《Journal of the European Ceramic Society》1999,19(16):913-2796
This study reports on the pyrolysis and densifaction behavior of cross-linked poly(hydridomethylsilazane) powders. The influence of the cross-linking procedure such as temperature and annealing time of the polymer powders on the compaction behavior under cold and warm pressing conditions is discussed. The degree of cross-linking is determined by thermal mechanical analysis (TMA). In addition to particle sliding which is assumed to be the compaction mechanism obtained by cold-pressing, the polymer powder consolidates by plastic deformation applying warm-pressing. A continuous 3-dimensional polysilazane network is formed after a dwelling time under these conditions. Pyrolysis of the cross-linked and compacted polysilazane powder in argon at 1100°C gives crack-free amorphous silicon carbonitride Si3+xCx+yN4 with compositions ranging from x=1·47 and y=0·88 for cold pressed samples to x=1·47 and y=1·86 for warm pressed materials. The residual open porosity is significantly reduced from 10–15 vol% in the cold pressed specimens to 1·3–5 vol% by the warm pressing procedure. The weight loss during pyrolysis between room temperature and 1300°C is about 5 wt% lower than that for cold pressed specimens. This result is explained by a reduced methane evolution during the polymer-to-ceramic conversion and is in accordance with the enhanced carbon content of the warm pressed material. 相似文献
110.
A review is given on the structure, chemistry, and assembly of crystalline bacterial cell surface layers (S-layers). S-layers composed of single protein or glycoprotein species represent the most common cell surface structures observed in prokaryotic organisms. Isolated S-layer proteins possess the intrinsic property for recrystallization into isoporous monomolecular arrays in suspension and at a broad spectrum of surfaces (e.g. silicon, metals, polymers) and interfaces (e.g. air–liquid interface or lipid films). The well-defined arrangement of functional groups on S-layer lattices allows the binding of functional molecules (e.g. enzymes, antibodies, ligands) and particles in defined regular arrays. S-layers also represent templates for the formation of inorganic nanocrystal superlattices (e.g. Au, CdS, Pt) as required for molecular electronics and non-linear optics. Finally, S-layers can be used as the structural basis for a biomolecular construction kit involving all major species of biological molecules for applications in molecular nanotechnology, nanobiotechnology and biomimetics. 相似文献