全文获取类型
收费全文 | 544篇 |
免费 | 30篇 |
学科分类
工业技术 | 574篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 2篇 |
2021年 | 14篇 |
2020年 | 6篇 |
2019年 | 16篇 |
2018年 | 14篇 |
2017年 | 10篇 |
2016年 | 13篇 |
2015年 | 29篇 |
2014年 | 22篇 |
2013年 | 40篇 |
2012年 | 34篇 |
2011年 | 37篇 |
2010年 | 20篇 |
2009年 | 26篇 |
2008年 | 37篇 |
2007年 | 28篇 |
2006年 | 29篇 |
2005年 | 39篇 |
2004年 | 17篇 |
2003年 | 14篇 |
2002年 | 13篇 |
2001年 | 10篇 |
2000年 | 10篇 |
1999年 | 9篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 2篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有574条查询结果,搜索用时 15 毫秒
31.
32.
A semitheoretical equation of state has been used to correlate residual thermodynamic properties of heavy hydrocarbons. The correlation requires three characteristic molecular parameters obtained from liquid density and vapour pressure data. These parameters are presented for 61 hydrocarbons with molecular weights up to 560 and are correlated with molecular weight and structural features. The correlation is extended to narrow-boiling fractions. Molecular parameters for such fractions are obtained from experimental characterization data (molecular weight, aromaticity, naphthenicity and number of methyl groups per molecule). Calculated vapour pressures and liquid densities are in reasonable agreement with new experimental results obtained from Belridge crude oil. 相似文献
33.
An Al96.1–Cu3.9 to Al51.4–Cu48.6 material library was obtained by thermal co-deposition and characterized by EDX and XRD. The crystallographic data reveals the presence of Al2Cu and pure aluminium depending on the film composition and following the stoichiometry. Utilizing a scanning droplet cell setup, the zero current potential for anodization, the oxide formation factor and the dielectric constant of the oxide formed are presented with high resolution along the composition gradient.While the dielectric constant of the oxide formed remains nearly unaffected by the increasing copper content of the base material along the composition gradient, the zero current potential shows well defined steps between 6.9 and 8.5 at.% as well as between 20.9 and 26.7 at.% copper indicating an increased thickness of the native oxide present on the film. Additionally, starting around 25 at.% copper, oxygen evolution gradually superimposes the oxide growth and in turn significantly reduces the current efficiency for anodization. The formation of the intermetallic phase Al2Cu was linked to both phenomena as it promotes the growth of native oxides and current leakage by oxygen evolution. 相似文献
34.
Achim Neubrand Reinhard Lindner Peter Hoffmann 《Journal of the American Ceramic Society》2000,83(4):860-864
In the present study, the incongruent dissolution of barium from barium titanate (BaTiO3 ) has been studied as a function of dispersion pH and powder volume fraction for two different BaTiO3 powders. In alkaline dispersions, the barium solubility strongly increases as the pH increases, as suggested by thermodynamic considerations. At pH <7, the barium solubility reaches a plateau, the height of which is dependent on the surface area of the powder and the solids loading of the slip. The BaTiO3 surface is completely depleted of barium in this region. 相似文献
35.
This paper describes the system dimensioning and the radio network planning methodology for a third generation wcdma system. The applicability of each method is demonstrated using examples of likely system scenarios. The challenges of modeling the multiservice environment are described and the implications to the system performance simulations are introduced. 相似文献
36.
Flatband potentials, charge carrier concentrations and their frequency dispersions of p-type and n-type InP in 1.0 M HCl were determined. The cathodic decomposition of InP in this acidic solution is compared with the deposition process of indium from 1.0 M-HCl containing 0.1 M InCl3. The share of the involved reactions, hydrogen evolution, InP decomposition and indium deposition are investigated. The reaction rates are generally smaller on p-type InP and the reaction speed is much slower but the principal reactions are the same. The kinetics of the indium deposition and dissolution are studied in detail. These reactions are discussed in terms of the preparation of watersplitting photoelectrodes with modified surfaces. 相似文献
37.
Aufgrund vieler Untersuchungen zur Standsicherheit von Eissporthallen wurde festgestellt, dass diese in unterschiedlichem Maße saniert werden müssen. Die Holzfeuchtigkeit der Tragkonstruktionen betrug meistens langanhaltend über 20 %. Daher wurden Untersuchungen zu den Ursachen hoher Holzfeuchten in Eissporthallen durchgeführt. Eine der Ursachen liegt in dem Strahlungsaustausch zwischen der Hallendecke und der Eisfläche. Zu dieser Problematik wurden Versuche durchgeführt und daraus mögliche Verbesserungsvorschläge für Eissporthallen abgeleitet. About the humidity problem in ice rinks. After expertising the structural safety of several ice rinks, it was detected that the constructions of several buildings have to be redeveloped. The long lasting wood moisture of the main structure was predominantly over 20 %. Therefore research into the reason of high wood moisture in ice rinks was made. One fact is the exchange of radiation between the ceiling and the ice. This problem was analysed in tests and suggestions for improvement are made. 相似文献
38.
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
39.
Achim Schmidt-Rodenkirchen Prof. Dr. Thorsten Gerdes Dr. Klaus Hintzer Dr. Michael Schlipf 《化学,工程师,技术》2023,95(8):1215-1227
In fluoropolymers, a large portion or even all of the hydrogen atoms in a polymer chain are replaced by fluorine, which results in a number of special properties such as high chemical and temperature resistance. As a result of this combination of properties, these high-performance polymers are not replaceable, or only with difficulty, for some applications. The recycling of polymers and the associated closing of material loops is an essential development task for the entire polymer industry. Materials such as fluoropolymers have a special position due to their chemical composition and their low market volume, as they cannot be recycled together with other bulk polymers at the end of their life cycle. This paper discusses different processes in terms of their technical maturity and suitability to allow fluoropolymers to be fully recycled. 相似文献
40.
Nargess Sadaghzadeh N. Javad Poshtan Achim Wagner Eugen Nordheimer Essameddin Badreddin 《ISA transactions》2014
Based on a cascaded Kalman–Particle Filtering, gyroscope drift and robot attitude estimation method is proposed in this paper. Due to noisy and erroneous measurements of MEMS gyroscope, it is combined with Photogrammetry based vision navigation scenario. Quaternions kinematics and robot angular velocity dynamics with augmented drift dynamics of gyroscope are employed as system state space model. Nonlinear attitude kinematics, drift and robot angular movement dynamics each in 3 dimensions result in a nonlinear high dimensional system. To reduce the complexity, we propose a decomposition of system to cascaded subsystems and then design separate cascaded observers. This design leads to an easier tuning and more precise debugging from the perspective of programming and such a setting is well suited for a cooperative modular system with noticeably reduced computation time. Kalman Filtering (KF) is employed for the linear and Gaussian subsystem consisting of angular velocity and drift dynamics together with gyroscope measurement. The estimated angular velocity is utilized as input of the second Particle Filtering (PF) based observer in two scenarios of stochastic and deterministic inputs. Simulation results are provided to show the efficiency of the proposed method. Moreover, the experimental results based on data from a 3D MEMS IMU and a 3D camera system are used to demonstrate the efficiency of the method. 相似文献