全文获取类型
收费全文 | 2031篇 |
免费 | 102篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 36篇 |
综合类 | 6篇 |
化学工业 | 631篇 |
金属工艺 | 54篇 |
机械仪表 | 43篇 |
建筑科学 | 125篇 |
矿业工程 | 9篇 |
能源动力 | 48篇 |
轻工业 | 135篇 |
水利工程 | 6篇 |
无线电 | 143篇 |
一般工业技术 | 365篇 |
冶金工业 | 121篇 |
原子能技术 | 28篇 |
自动化技术 | 388篇 |
出版年
2023年 | 21篇 |
2022年 | 35篇 |
2021年 | 65篇 |
2020年 | 35篇 |
2019年 | 36篇 |
2018年 | 39篇 |
2017年 | 40篇 |
2016年 | 74篇 |
2015年 | 57篇 |
2014年 | 63篇 |
2013年 | 94篇 |
2012年 | 114篇 |
2011年 | 147篇 |
2010年 | 115篇 |
2009年 | 95篇 |
2008年 | 112篇 |
2007年 | 95篇 |
2006年 | 109篇 |
2005年 | 77篇 |
2004年 | 77篇 |
2003年 | 49篇 |
2002年 | 42篇 |
2001年 | 40篇 |
2000年 | 34篇 |
1999年 | 38篇 |
1998年 | 39篇 |
1997年 | 33篇 |
1996年 | 25篇 |
1995年 | 22篇 |
1994年 | 25篇 |
1993年 | 20篇 |
1992年 | 22篇 |
1991年 | 21篇 |
1990年 | 16篇 |
1989年 | 15篇 |
1988年 | 10篇 |
1987年 | 15篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1983年 | 11篇 |
1982年 | 12篇 |
1981年 | 11篇 |
1980年 | 13篇 |
1979年 | 11篇 |
1978年 | 9篇 |
1977年 | 10篇 |
1976年 | 8篇 |
1975年 | 15篇 |
1974年 | 16篇 |
1973年 | 7篇 |
排序方式: 共有2138条查询结果,搜索用时 15 毫秒
91.
We consider the distributed realizability problem for systems with regular and deterministic contextfree local specifications. We characterize exactly the architectures for which the realizability problem is decidable. This extends known results on local specifications in two directions. First, architectures with cycles are allowed instead of just acyclic ones and second, deterministic contextfree specifications are considered. 相似文献
92.
It is of high technical importance to consider the loading and unloading dynamics of hydride-based hydrogen storage tanks, which are mainly influenced by the heat and gas transfer properties inside the reaction bed. In this regard, hydride-graphite composites offer improved heat transfer properties and higher volumetric storage capacities compared to commonly used powder beds. 相似文献
93.
94.
Christina Skiera Panagiotis Steliopoulos Thomas Kuballa Ulrike Holzgrabe Bernd Diehl 《Journal of the American Oil Chemists' Society》2012,89(8):1383-1391
Within the course of lipid peroxidation, hydroperoxides are formed as primary products. They can be used as analytical markers
to assess the deterioration status of oils and fats. Here a new 1H-NMR assay to determine the hydroperoxide amount in edible oils is presented. We were able to show that the analytical performance
of the method is similar to that of the commonly used peroxide value (PV) according to Wheeler. A total of 290 edible oil
samples were analyzed using both methods. For some oil varieties considerable discrepancies were found between the results
obtained. In the case of black seed and olive oil, two substances could be identified that cause positive (black seed oil)
and negative (olive oils) deviations from the theoretical PV expected from the NMR values. 相似文献
95.
Dr. Holger Siebeneicher Dr. Arwed Cleve Dr. Hartmut Rehwinkel Dr. Roland Neuhaus Dr. Iring Heisler Dr. Thomas Müller Dr. Marcus Bauser Dr. Bernd Buchmann 《ChemMedChem》2016,11(20):2261-2271
Despite the long‐known fact that the facilitative glucose transporter GLUT1 is one of the key players safeguarding the increase in glucose consumption of many tumor entities even under conditions of normal oxygen supply (known as the Warburg effect), only few endeavors have been undertaken to find a GLUT1‐selective small‐molecule inhibitor. Because other transporters of the GLUT1 family are involved in crucial processes, these transporters should not be addressed by such an inhibitor. A high‐throughput screen against a library of ~3 million compounds was performed to find a small molecule with this challenging potency and selectivity profile. The N‐(1H‐pyrazol‐4‐yl)quinoline‐4‐carboxamides were identified as an excellent starting point for further compound optimization. After extensive structure–activity relationship explorations, single‐digit nanomolar inhibitors with a selectivity factor of >100 against GLUT2, GLUT3, and GLUT4 were obtained. The most promising compound, BAY‐876 [N4‐[1‐(4‐cyanobenzyl)‐5‐methyl‐3‐(trifluoromethyl)‐1H‐pyrazol‐4‐yl]‐7‐fluoroquinoline‐2,4‐dicarboxamide], showed good metabolic stability in vitro and high oral bioavailability in vivo. 相似文献
96.
Christian Immanuel Müller Thomas Rauscher Andreas Schmidt Thomas Schubert Thomas Weißgärber Bernd Kieback Lars Röntzsch 《International Journal of Hydrogen Energy》2014
In this work different amorphous melt-spun Fe-alloys (Fe82B18, Fe80Si10B10, Fe60Co20Si10B10) were investigated as cathode materials for the alkaline electrolysis of water. In particular, the influence of cobalt as well as the metalloids boron and silicon on the activity for the hydrogen evolution reaction (HER) was studied in 1 M KOH at 298 K using cyclic voltammetric, galvanostatic and polarization techniques. The electrocatalytic activity was evaluated in the view of the overpotential. It was found that cyclic voltammetric techniques can be used to activate the melt-spun Fe-alloys strongly. Different cyclic voltammetric activation procedures are discussed and the influence of the sweep rate and the potential window on the HER activity was elucidated. The experimental data indicate that the addition of metalloids and, most importantly, of cobalt improves the HER activity of the materials. Thus, the overpotential can be reduced by 200 mV compared to polycrystalline Ni. 相似文献
97.
Revolute joints in applications always show clearance between pin and bushing due to manufacturing tolerances, the need of relative motion or progressing wear. Many researchers developed and investigated methodologies to calculate the dynamic behavior of mechanisms with such imperfect joints. Very often they use a simple slider-crank mechanism to test or demonstrate the capability of their approaches. In this paper, a methodology for simulating a slider-crank mechanism with an imperfect revolute joint in RecurDyn, a commercial multibody simulation tool, is presented. Therefore, a thorough investigation of existing contact, damping and friction force models as well as different ways of modeling revolute joints in RecurDyn was conducted. For the investigation of the damping models, a special program for calculating the model parameters for a given coefficient of restitution was developed. Only one damping model was capable of reproducing the experimental results, which were found in literature. Some characteristic results of the slider-crank mechanism are presented in a way that they can be compared to results in other papers. Thereby. a good correlation was achieved, demonstrating the capabilities of the methodology. 相似文献
98.
Changing behaviours and attitudes towards more sustainable individual energy consumption is a difficult topic to address. After identifying the most recurrent factors influencing the bad energy consumption, society's environmental short-sightedness, a lack of individual responsibility and a tendency to put responsibility upon firms, institutions, and governments, the authors evaluated the effect that business practices can have on individual behaviour. By qualifying as highly credible sources of information, positioning themselves as examples to follow, and providing its employees with the necessary smart and innovative technology, business communities can have a major impact on changing individual behaviours towards more sustainable energy consumption. 相似文献
99.
100.
Bernd Garska Monir Tabatabai Urs Fischer Norbert Moszner Andreas Utterodt Helmut Ritter 《Polymer International》2012,61(7):1061-1066
We describe the synthesis of 5,11,17,23‐tetra‐tert‐butyl‐25,27‐dioxypropylphosphonic acid‐26,28‐dimethacryloyloxy‐calix [4]arene and 5,11,17,23‐tetra‐tert‐butyl‐25‐oxypropylphosphonic acid‐27‐hydroxy‐26,28‐dimethacryloyloxy‐calix[4]arene starting from para‐tert‐butyl‐calix[4]arene. The complete reaction was proved by matrix‐assisted laser desorption ionization time of flight mass spectrometry and nuclear magnetic resonance spectroscopy. The influence of these compounds on the kinetics of the radical polymerization of methyl methacrylate was shown by dilatometry. Furthermore, the adhesive properties of dental adhesives containing these calix[4]arene derivatives were investigated. Copyright © 2012 Society of Chemical Industry 相似文献