全文获取类型
收费全文 | 1269篇 |
免费 | 50篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 13篇 |
综合类 | 6篇 |
化学工业 | 245篇 |
金属工艺 | 28篇 |
机械仪表 | 37篇 |
建筑科学 | 38篇 |
矿业工程 | 1篇 |
能源动力 | 14篇 |
轻工业 | 285篇 |
水利工程 | 3篇 |
无线电 | 67篇 |
一般工业技术 | 222篇 |
冶金工业 | 239篇 |
原子能技术 | 17篇 |
自动化技术 | 105篇 |
出版年
2021年 | 21篇 |
2020年 | 15篇 |
2018年 | 26篇 |
2017年 | 23篇 |
2016年 | 20篇 |
2015年 | 26篇 |
2014年 | 12篇 |
2013年 | 68篇 |
2012年 | 36篇 |
2011年 | 40篇 |
2010年 | 39篇 |
2009年 | 36篇 |
2008年 | 25篇 |
2007年 | 40篇 |
2006年 | 36篇 |
2005年 | 19篇 |
2004年 | 26篇 |
2003年 | 20篇 |
2002年 | 24篇 |
2001年 | 18篇 |
2000年 | 14篇 |
1999年 | 16篇 |
1998年 | 77篇 |
1997年 | 49篇 |
1996年 | 35篇 |
1995年 | 34篇 |
1994年 | 34篇 |
1993年 | 17篇 |
1992年 | 16篇 |
1990年 | 15篇 |
1989年 | 16篇 |
1988年 | 18篇 |
1987年 | 18篇 |
1986年 | 14篇 |
1985年 | 15篇 |
1984年 | 15篇 |
1983年 | 15篇 |
1982年 | 17篇 |
1981年 | 17篇 |
1980年 | 17篇 |
1979年 | 17篇 |
1978年 | 28篇 |
1977年 | 26篇 |
1976年 | 31篇 |
1975年 | 19篇 |
1974年 | 18篇 |
1973年 | 21篇 |
1972年 | 12篇 |
1971年 | 17篇 |
1970年 | 11篇 |
排序方式: 共有1320条查询结果,搜索用时 375 毫秒
81.
L. Bencze D. D. Raj D. Kath L. Singheiser K. Hilpert W. A. Oates J. Herrmann 《Metallurgical and Materials Transactions A》2003,34(11):2409-2419
The vaporization of Fe-Al alloys has been investigated in the temperature range of 1140 to 1600 K by Knudsen effusion mass
spectrometry. Eleven different compositions were examined in the composition range between 30 and 51 at. pct Al, mostly in
the B2 region of the phase diagram. The partial pressures and thermodynamic activities of both Fe and Al were evaluated: directly
from the measured ion intensities for a component in both the alloy and the pure element, I
M
+
/I
M
+0
, and also from the ion-intensity ratios of the alloy components, I
Al
+
/I
Fe
+
, by means of a Gibbs-Duhem integration. Reliable partial and integral molar enthalpies and entropies of mixing have been
obtained by mass spectrometry for this system for the first time. Nearly temperature-independent integral enthalpies and entropies
of mixing over the wide temperature range investigated were found, with the mixing entropies being large and negative. 相似文献
82.
83.
Kraft E. Fischer P. Karagounis M. Koch M. Krueger H. Peric I. Wermes N. Herrmann C. Nascetti A. Overdick M. Ruetten W. 《IEEE transactions on nuclear science》2007,54(2):383-390
A novel signal processing concept for X-ray imaging with directly converting pixelated semiconductor sensors is presented. The novelty of this approach compared to existing concepts is the combination of charge integration and photon counting in every single pixel. Simultaneous operation of both signal processing chains extends the dynamic range beyond the limits of the individual schemes and allows determination of the mean photon energy. Medical applications such as X-ray computed tomography can benefit from this additional spectral information through improved contrast and the ability to determine the hardening of the tube spectrum due to attenuation by the scanned object. A prototype chip in 0.35-micrometer technology has been successfully tested. The pixel electronics are designed using a low-swing differential current mode logic. Key element is a configurable feedback circuit for the charge sensitive amplifier which provides continuous reset, leakage current compensation and replicates the input signal for the integrator. This paper will discuss measurement results of the prototype structures and give details on the circuit design 相似文献
84.
85.
Impact of the Nanoscale Gap Morphology on the Plasmon Coupling in Asymmetric Nanoparticle Dimer Antennas
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)
Paul S. Popp Janning F. Herrmann Eva‐Corinna Fritz Bart Jan Ravoo Christiane Höppener 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(12):1667-1675
Coupling of plasmon resonances in metallic gap antennas is of interest for a wide range of applications due to the highly localized strong electric fields supported by these structures, and their high sensitivity to alterations of their structure, geometry, and environment. Morphological alterations of asymmetric nanoparticle dimer antennas with (sub)‐nanometer size gaps are assigned to changes of their optical response in correlative dark‐field spectroscopy and high‐resolution transmission electron microscopy (HR‐TEM) investigations. This multimodal approach to investigate individual dimer structures clearly demonstrates that the coupling of the plasmon modes, in addition to well‐known parameters such as the particle geometry and the gap size, is also affected by the relative alignment of both nanoparticles. The investigations corroborate that the alignment of the gap forming facets, and with that the gap area, is crucial for their scattering properties. The impact of a flat versus a rounded gap structure on the optical properties of equivalent dimers becomes stronger with decreasing gap size. These results hint at a higher confinement of the electric field in the gap and possibly a different onset of quantum transport effects for flat and rounded gap antennas in corresponding structures for very narrow gaps. 相似文献
86.
Jerzy Cierniewski Arnon Karnieli Ittai Herrmann Sławomir Królewicz Krzysztof Kuśnierek 《International journal of remote sensing》2013,34(8):2151-2157
The results of the paper draw attention to the fact that the hyperspectral image of soil surface at micro-relief scale may display variation in the soil spectral shape due to illumination conditions of the surface. The image of an extremely rough cultivated soil surface, very deeply ploughed, was obtained by a hyperspectral camera, in the range of 0.4–1.0 μm with 0.67–0.74 nm spectral resolution. It was found that the soil reflectance spectra of the studied surface, illuminated by the direct sunbeams, are clearly convex with distinct absorption features. Furthermore, the soil normalized reflectance spectra were used to distinguish the subtlety of the analysed shaded soil spectra shape. They show that depressions caused by the absorption features of O2 and H2O, contained in the atmosphere above directly illuminated soil fragments, transform into peaks, if the same soil is deeply shaded. 相似文献
87.
Jerzy Cierniewski Arnon Karnieli Krzysztof Kuśnierek Alexander Goldberg Ittai Herrmann 《International journal of remote sensing》2013,34(9-10):3416-3424
The present study explores the diurnal variations in blue-sky albedo (α) of soils under clear sky conditions with respect to surface roughness. Three roughness levels of ploughed and unploughed soil surfaces, developed from the same loessial material, were examined. The relation between α of the surfaces and the solar zenith angle, determined during the experiment, enabled us to predict the diurnal α variation of the surfaces throughout the year at a given latitude, between 75° S and 75° N. The optimal time (T O) for measuring the soil albedo by an instantaneous observation was considered as the best represented time for the daily averaged value within an error lower than ±2%. It was found that the T O, falling at different times depending on the soil surface roughness, limits the possibilities of data achievement by remote-sensing satellites along one of their sun-synchronous orbits. 相似文献
88.
G. Herrmann 《Holz als Roh- und Werkstoff》1979,37(5):179-182
The wide variety of transport systems nowadays available for kiln dryers sometimes makes it difficult for the future costumer to find the optimum layout for his purposes. In this paper, recommendations as to the selection of the most suitable equipment are given. The specific requirements of a company differ greatly in the practice and should always be considered in the overall layout. In the present paper the pros and cons of the most common lypes of transport systems are described. 相似文献
89.