全文获取类型
收费全文 | 408篇 |
免费 | 16篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 38篇 |
化学工业 | 77篇 |
金属工艺 | 7篇 |
机械仪表 | 9篇 |
建筑科学 | 9篇 |
能源动力 | 13篇 |
轻工业 | 14篇 |
石油天然气 | 2篇 |
无线电 | 44篇 |
一般工业技术 | 79篇 |
冶金工业 | 72篇 |
原子能技术 | 4篇 |
自动化技术 | 57篇 |
出版年
2023年 | 11篇 |
2022年 | 6篇 |
2021年 | 15篇 |
2020年 | 11篇 |
2019年 | 10篇 |
2018年 | 14篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 7篇 |
2014年 | 10篇 |
2013年 | 29篇 |
2012年 | 17篇 |
2011年 | 22篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 14篇 |
2007年 | 18篇 |
2006年 | 11篇 |
2005年 | 7篇 |
2004年 | 10篇 |
2003年 | 9篇 |
2002年 | 9篇 |
2001年 | 6篇 |
2000年 | 11篇 |
1999年 | 7篇 |
1998年 | 13篇 |
1997年 | 15篇 |
1996年 | 11篇 |
1995年 | 3篇 |
1994年 | 8篇 |
1993年 | 6篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 4篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 5篇 |
1982年 | 4篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1969年 | 2篇 |
1967年 | 2篇 |
1946年 | 1篇 |
1945年 | 1篇 |
1944年 | 1篇 |
1942年 | 1篇 |
排序方式: 共有425条查询结果,搜索用时 15 毫秒
1.
Olga Sambalova Emanuel Billeter Oguz Yildirim Andrea Sterzi Davide Bleiner Andreas Borgschulte 《International Journal of Hydrogen Energy》2021,46(5):3346-3353
External magnetic fields affect various electrochemical processes and can be used to enhance the efficiency of the electrochemical water splitting reaction. However, the driving forces behind this effect are poorly understood due to the analytical challenges of the available interface-sensitive techniques. Here, we present a set-up based on magneto- and electro-optical probing, which allows to juxtapose the magnetic properties of the electrode with the electrochemical current densities in situ at various applied potentials and magnetic fields. On the example of an archetypal hydrogen evolution catalyst, Pt (in a form of Co/Pt superlattice), we provide evidence that a magnetic field acts on the electrochemical double layer affecting the local concentration gradient of hydroxide ions, which simultaneously affects the magneto-optical and magnetocurrent response. 相似文献
2.
Emanuel Gluskin 《International Journal of Circuit Theory and Applications》2015,43(4):524-543
The suggestion of writing, for some problems, nonlinear state equations not as dx/dt = F(x,u,t), but as dx/dt = [A(t,x)]x + [B(t,x)]u(t), which is more ‘constructive’ as re system perception and possible structural generalizations, is considered, supported by arguments related to the classification of switched circuits as linear and nonlinear. The point of the distinction is mainly that when solving dx/dt = F(x,u,t), one immediately dwells into the analytical problems related to pure mathematics, whereas for dx/dt = [A(t,x)]x + [B(t,x)]u(t), considering first a constant matrix [A], one introduces the system's physical structure and considering then [A(x)] sees the nonlinearity of the system as a dependence of the structure on the processes in it or on system's input. (This might be named structural response). The thinking in terms of structure better observes the engineering and physical degrees of freedom, which are relevant regarding applications. Some electronic systems and physical systems (e.g., hydrodynamic) are considered in these terms. The logical side is always the focus, and the pedagogical (even philosophical) side is not ignored. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
3.
Nicolás Emanuel Tenaglia Roberto Enrique Boeri Juan Miguel Massone Alejandro Daniel Basso 《Materials Science & Technology》2018,34(16):1990-2000
The austemperability of seven high silicon cast steels with different alloy contents was characteri sed. The maximum round bar diameter that can be fully austempered changed from about 10?mm for an unalloyed steel to more than 70?mm for a low-alloy steel. The austemperability was calculated by applying a procedure based on a standard Jominy test and the characterisation of the microstructure along the Jominy sample. The method, which was validated experimentally, creates a relatively simple procedure to measure austemperability. Processing factors such as the ability of the salt bath to extract heat and the austempering temperature are accounted for the method. The metallographic study revealed the influence of microsegregation on hardenability, which is particularly important for cast steels. 相似文献
4.
Imide‐containing ladder polyphenylsilsesquioxanes with high thermal stability and thermoplastic properties 下载免费PDF全文
This work reports for the first time the synthesis of ladder polyphenylsilsesquioxanes containing imide building blocks as parts of the main parallel chains. The ladder structure of the synthesized polymers was documented by means of small angle X‐ray scattering (SAXS) measurements. The obtained ladder polymers exhibit stability with respect to decomposition up to temperatures as high as 460°C; additionally, they have melting points far below their decomposition temperatures, which make them interesting candidate materials for thermoplastic processing. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40085. 相似文献
5.
Scientometrics - This country case study describes how science policy instruments are designed to shape publication patterns and identifies the changes in researchers’ productivity that can... 相似文献
6.
Emanuel Parzen 《技术计量学》2013,55(4):473-474
Residuals from fit are often examined in regression analysis. A test suggested by Ellenberg [5] and Prescott [7] for the largest residual being an outlier is implemented through table development. Tables of critical valltes for tests at levels (α ≤ 0.10, 00.5, and 0.01 are included. 相似文献
7.
Emanuel Gluskin 《International journal of systems science》2013,44(6):753-766
A formula for the input conductivity characteristic of an infinite grid of similar, weakly nonlinear resistors (conductors) measured between two nodes is obtained using a specific approximate representation of the grid. This formula is more precise than the corresponding formula given earlier by Gluskin. Some hypotheses concerning the analytical features of the input resistive (conductive) function, not necessarily associated with weak nonlinearity, and also related to circuits of other topologies, are considered. One of the hypotheses leads to a simplified method of calculation of the input conductivity, which has a reasonable engineering precision and may replace incomparably more difficult calculations. The derivations are given in detail. 相似文献
8.
9.
“Manned-Unmanned Teaming” among others refers to the use of an unmanned, flying sensor. One use for this is as an integral part of air units’ flying systems. Secondly, it can be used as an independent, recessed robotic component during missions, even from far away and ahead of time. As part of the German R&T project “Manned- Unmanned Teaming” (MUM-T), Elektroniksystem- und Logistik-GmbH (ESG) was assigned the task of investigating these concepts and the options for their realization. The focus of the investigation was initial operation capability within a narrow time frame concentrating on German Army Aviation helicopters. The paper focuses on the results achieved by ESG and begins with a short project overview. In the main part a representative MUM-T mission based on a personnel recovery mission is presented. The mission was demonstrated by ESG in close cooperation with German Army Aviation Combat Development Division (Ger AAV CDD). Beside operational aspects, technical aspects will be discussed. The lecture will close with a short outlook on the next steps, bringing MUM-T missions into service. 相似文献
10.
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