全文获取类型
收费全文 | 315篇 |
免费 | 40篇 |
专业分类
电工技术 | 8篇 |
综合类 | 1篇 |
化学工业 | 112篇 |
金属工艺 | 8篇 |
机械仪表 | 9篇 |
建筑科学 | 7篇 |
矿业工程 | 2篇 |
能源动力 | 19篇 |
轻工业 | 16篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 38篇 |
一般工业技术 | 77篇 |
冶金工业 | 7篇 |
原子能技术 | 3篇 |
自动化技术 | 45篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 9篇 |
2021年 | 19篇 |
2020年 | 26篇 |
2019年 | 9篇 |
2018年 | 27篇 |
2017年 | 25篇 |
2016年 | 14篇 |
2015年 | 17篇 |
2014年 | 14篇 |
2013年 | 25篇 |
2012年 | 21篇 |
2011年 | 24篇 |
2010年 | 21篇 |
2009年 | 25篇 |
2008年 | 22篇 |
2007年 | 10篇 |
2006年 | 7篇 |
2005年 | 6篇 |
2004年 | 1篇 |
2003年 | 3篇 |
2002年 | 5篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 5篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1978年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有355条查询结果,搜索用时 15 毫秒
11.
12.
The study analyses the fuelwood characteristics of 26 trees including shrub species from the dry deciduous forest in Aravally region, Rajasthan, Western India was carried out to explore trees with potential for fuelwood production. Fuelwood value index (FVI) based on the properties of calorific value, wood density and ash. Calorific value was ranged between 18.54 ± 0.04 and 27.44 ± 0.09 KJ g−1 in Jatropha curcus and Wrightia tinctoria respectively. Wood density varied from 0.538 ± 0.01 to 0.966 ± 0.07 g/cm3 in J. curcus and Acacia nilotica. Same way ash and moisture content was highest in J. curcus (3.38 ± 0.19%) and Sterculia urens (70.28 ± 7.52%) and lowest in Miliusa tomentosa (0.85 ± 0.06%) and Azadirachta indica (30.7 ± 10.02%) respectively. On the basis, of the 26 species analyzed, M. tomentosa has the highest FVI, followed by Lannea coromandelica, Acacia leucophloea, Madhuca indica, A. nilotica, W. tinctoria, Butea monosperma, Zizyphus nummularia, S. urens, Boswellia serrata, A. indica, Grewia tenax, Syzygium cuminii, Tectona grandis and Dalbergia sissoo were shown to have promising fuelwood production. 相似文献
13.
Photoswitchable Membranes Based on Peptide‐Modified Nanoporous Anodic Alumina: Toward Smart Membranes for On‐Demand Molecular Transport
下载免费PDF全文
![点击此处可从《Advanced materials (Deerfield Beach, Fla.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
14.
15.
Theoretical and Experimental Insight into the Mechanism for Spontaneous Vertical Growth of ReS2 Nanosheets
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Debjit Ghoshal Anthony Yoshimura Tushar Gupta Andrew House Swastik Basu Yanwen Chen Tianmeng Wang Yang Yang Wenjia Shou Jordan A. Hachtel Juan Carlos Idrobo Toh‐Ming Lu Sagnik Basuray Vincent Meunier Su‐Fei Shi Nikhil Koratkar 《Advanced functional materials》2018,28(30)
Rhenium disulfide (ReS2) differs fundamentally from other group‐VI transition metal dichalcogenides (TMDs) due to its low structural symmetry, which results in its optical and electrical anisotropy. Although vertical growth is observed in some TMDs under special growth conditions, vertical growth in ReS2 is very different in that it is highly spontaneous and substrate‐independent. In this study, the mechanism that underpins the thermodynamically favorable vertical growth mode of ReS2 is uncovered. It is found that the governing mechanism for ReS2 growth involves two distinct stages. In the first stage, ReS2 grows parallel to the growth substrate, consistent with conventional TMD growth. However, subsequent vertical growth is nucleated at points on the lattice where Re atoms are “pinched” together. At such sites, an additional Re atom binds with the cluster of pinched Re atoms, leaving an under‐coordinated S atom protruding out of the ReS2 plane. This under‐coordinated S is “reactive” and binds to free Re and S atoms, initiating growth in a direction perpendicular to the ReS2 surface. The utility of such vertical ReS2 arrays in applications where high surface‐to‐volume ratio and electric‐field enhancement are essential, such as surface enhanced Raman spectroscopy, field emission, and solar‐based disinfection of bacteria, is demonstrated. 相似文献
16.
Yogesh S. Kashyap Ashish Agrawal P.S. Sarkar Mayank Shukla Tushar Roy Amar Sinha 《NDT & E International》2011,44(1):41-46
We have used the contrast transfer function based X-ray phase retrieval technique for phase retrieval studies on a two-component system. Pyro-carbon coated alumina matrix was chosen as a two-component system for these studies. Simulations as well as experimental results are presented. This paper shows that X-ray phase contrast along with phase retrieval can become an alternative tool for non-destructive characterization of these materials. We have also attempted to retrieve the spatial distribution of the projected thickness map of the two different elements. 相似文献
17.
Tushar Borkar John Sosa Jun Yeon Hwang Thomas W. Scharf Jaimie Tiley Hamish Fraser Rajarshi Banerjee 《JOM Journal of the Minerals, Metals and Materials Society》2014,66(6):935-942
A new class of Ni-Ti-C-based metal-matrix composites has been developed using the laser-engineered net shaping? process. These composites consist of an in situ formed and homogeneously distributed titanium carbide (TiC) phase reinforcing the nickel matrix. Additionally, by tailoring the Ti/C ratio in these composites, an additional graphitic phase can also be engineered into the microstructure. Serial-sectioning, followed by three-dimensional reconstruction of the microstructure in these composites, reveals homogeneously distributed primary and eutectic titanium carbide precipitates as well as a graphitic phase encompassing the primary carbides within the nickel matrix. The morphology and spatial distribution of these phases in three dimensions reveals that the eutectic carbides form a network linked by primary carbides or graphitic nodules at the nodes, which suggests interesting insights into the sequence of phase evolution. These three-phase Ni-TiC-C composites exhibit excellent tribological properties, in terms of an extremely low coefficient of friction while maintaining a relatively high hardness. 相似文献
18.
Suresh Bhalla Praveen Kumar Ashok Gupta Tushar K. Datta 《Canadian Metallurgical Quarterly》2009,22(4):373-382
The electromechanical impedance technique employs surface-bonded lead zirconate titanate piezoelectric ceramic patches as impedance transducers for structural health monitoring and nondestructive evaluation. The patches are bonded to the monitored structures using finitely thick adhesive bond layer, which introduces shear lag effect, thus invariably influencing the electromechanical admittance signatures. This paper presents a new simplified impedance model to incorporate shear lag effect into electromechanical admittance formulations, both one-dimensional and two-dimensional. This provides a closed-form analytical solution of the inverse problem, i.e. to derive the true structural impedance from the measured conductance and susceptance signatures, thus an improvement over the existing models. The influence of various parameters (associated with the bond layer) on admittance signatures is investigated using the proposed model and the results compared with existing models. The results show that the new model, which is far simpler than the existing models, models the shear lag phenomenon reasonably well besides providing direct solution of a complex inverse problem. 相似文献
19.
A core-envelope model for a spherical superdense distribution of matter is reported, with a core consisting of anisotropic
fluid engulfed by an envelope containing fluid with isotropic pressure is reported. The background space-time of the whole
configuration is characterized by a two-parameter parabolic geometry. The physical plausibility of the model is examined both
analytically and numerically, and suitability of the model for describing space-times of superdense stars containing strange
matter, such as Her-X1 and SAX, is also discussed. 相似文献
20.
Tushar S. Basu Baul Pradip Das George Eng Anthony Linden 《Journal of Inorganic and Organometallic Polymers and Materials》2010,20(1):134-141
Four new triphenyltin(IV) complexes containing [((E)-1-{2-hydroxy-5-[(E)-2-(aryl)-1-diazenyl]phenyl}methylidene)amino]acetate ligands (L) have been synthesized with formulations of Ph3SnLH. They have been studied by multinuclear (1H, 13C, 119Sn) NMR, 119Sn M?ssbauer and IR spectroscopy. A full characterization of one complex, Ph3SnL1H (1), was accomplished by single crystal X-ray crystallography, which revealed the compound to be a macrocyclic tetramer. In
the tetramer, the five coordinate tin atoms have distorted trigonal bipyramidal geometries with the three phenyl groups occupying
equatorial positions, while an oxygen atom of the carboxylate group of one L ligand and the oxide O-atom (formerly the hydroxy
group) of a second L ligand in an apical positions. The carboxylate ligands bridge adjacent tin atoms and coordinate in the
zwitterionic form with the phenolic proton moved to the nearby nitrogen atom. 119Sn NMR results indicate that the tetrameric structures of the complexes in the solid state, in which the tin atoms are five-coordinated,
dissociate in solution to yield four coordinate monomeric species. 相似文献