全文获取类型
收费全文 | 2850篇 |
免费 | 130篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 43篇 |
综合类 | 8篇 |
化学工业 | 669篇 |
金属工艺 | 52篇 |
机械仪表 | 26篇 |
建筑科学 | 184篇 |
矿业工程 | 7篇 |
能源动力 | 80篇 |
轻工业 | 224篇 |
水利工程 | 20篇 |
石油天然气 | 5篇 |
无线电 | 268篇 |
一般工业技术 | 556篇 |
冶金工业 | 341篇 |
原子能技术 | 26篇 |
自动化技术 | 474篇 |
出版年
2023年 | 38篇 |
2022年 | 41篇 |
2021年 | 108篇 |
2020年 | 57篇 |
2019年 | 63篇 |
2018年 | 59篇 |
2017年 | 62篇 |
2016年 | 96篇 |
2015年 | 74篇 |
2014年 | 125篇 |
2013年 | 146篇 |
2012年 | 163篇 |
2011年 | 203篇 |
2010年 | 127篇 |
2009年 | 132篇 |
2008年 | 149篇 |
2007年 | 135篇 |
2006年 | 126篇 |
2005年 | 110篇 |
2004年 | 87篇 |
2003年 | 62篇 |
2002年 | 63篇 |
2001年 | 34篇 |
2000年 | 49篇 |
1999年 | 50篇 |
1998年 | 100篇 |
1997年 | 67篇 |
1996年 | 59篇 |
1995年 | 44篇 |
1994年 | 42篇 |
1993年 | 30篇 |
1992年 | 16篇 |
1991年 | 23篇 |
1990年 | 15篇 |
1989年 | 17篇 |
1988年 | 12篇 |
1987年 | 14篇 |
1986年 | 10篇 |
1985年 | 16篇 |
1984年 | 9篇 |
1983年 | 14篇 |
1982年 | 12篇 |
1981年 | 13篇 |
1980年 | 8篇 |
1979年 | 12篇 |
1978年 | 11篇 |
1977年 | 12篇 |
1976年 | 19篇 |
1974年 | 7篇 |
1971年 | 6篇 |
排序方式: 共有2983条查询结果,搜索用时 31 毫秒
81.
Kristian Bredies Thomas Pock Benedikt Wirth 《Journal of Mathematical Imaging and Vision》2013,47(3):278-302
We investigate a class of variational problems that incorporate in some sense curvature information of the level lines. The functionals we consider incorporate metrics defined on the orientations of pairs of line segments that meet in the vertices of the level lines. We discuss two particular instances: One instance that minimizes the total number of vertices of the level lines and another instance that minimizes the total sum of the absolute exterior angles between the line segments. In case of smooth level lines, the latter corresponds to the total absolute curvature. We show that these problems can be solved approximately by means of a tractable convex relaxation in higher dimensions. In our numerical experiments we present preliminary results for image segmentation, image denoising and image inpainting. 相似文献
82.
Alexander Gredner Christoph Gerhard Stephan Wieneke Kai Schmidt Wolfgang Viol 《材料科学与工程:中英文B版...》2013,(6):346-351
In this work, a novel atmospheric pressure plasma-assisted excimer laser annealing method for increasing the generation efficiency of poly-crystalline silicon from amorphous silicon layers is presented. Here, both the plasma and the laser propagate coaxially in order to generate energetic synergies. The influence of different process gases and plasma discharge modes as well as the working distance were investigated. Depending on the particularly applied plasma, the crystalline area was increased by a factor of approx. 1.1 to 1.9, where the highest efficiency was observed when introducing an argon plasma beam to the annealing process. 相似文献
83.
Christoph Spiegel Manfred Kraut Georg Rabsch Christof Küsters Wolfgang Augustin Stephan Scholl 《化学工程与技术》2019,42(10):2067-2075
The application of highly effective microstructured devices in continuous production and industrial environments is frequently prone to fouling. A new method is presented to characterize fouling in these microstructures. Thermal fouling of aqueous solutions containing whey protein were used as a test system. Different fouling effects could be observed and distinguished. Integral fouling indicators, such as thermal fouling resistance and pressure drop, as conventional criteria for the occurrence of fouling were compared with direct local optical observation. Low thermal fouling resistances could be detected. 相似文献
84.
Felix Schubert Steffen Wirth Friederike Zimmermann Johannes Heitmann Thomas Mikolajick 《Science and Technology of Advanced Materials》2016,17(1):239-243
Growth conditions have a tremendous impact on the unintentional background impurity concentration in gallium nitride (GaN) synthesized by molecular beam epitaxy and its resulting chemical and physical properties. In particular for oxygen identified as the dominant background impurity we demonstrate that under optimized growth stoichiometry the growth temperature is the key parameter to control its incorporation and that an increase by 55?°C leads to an oxygen reduction by one order of magnitude. Quantitatively this reduction and the resulting optical and electrical properties are analyzed by secondary ion mass spectroscopy, photoluminescence, capacitance versus voltage measurements, low temperature magneto-transport and parasitic current paths in lateral transistor test structures based on two-dimensional electron gases. At a growth temperature of 665?°C the residual charge carrier concentration is decreased to below 1015 cm?3, resulting in insulating behavior and thus making the material suitable for beyond state-of-the-art device applications. 相似文献
85.
86.
Dmitry V. Volodkin Stephan Schmidt Paulo Fernandes Natalia I. Larionova Gleb B. Sukhorukov Claus Duschl Helmuth Möhwald Regine von Klitzing 《Advanced functional materials》2012,22(9):1914-1922
Formulation of therapeutic proteins into particulate forms is a main strategy for site‐specific and prolonged protein delivery as well as for protection against degradation. Precise control over protein particle size, dispersity, purity, as well as mild preparation conditions and minimal processing steps are highly desirable. It is, however, hard to fit all these criteria with conventional preparation techniques. Here a one‐step hard‐templating synthesis of microparticles composed of functional, non‐denatured protein is reported. The method is based on filling porous CaCO3 microtemplates with the protein near to its isoelectric point (pI) followed by pH‐ or EDTA‐mediated dissolution of the tempplates. In principle, a wide variety of proteins can be converted into microparticles using this approach. The main requirement is an overlap of the protein insolubility and a template solubility for a certain parameter (here pH or EDTA). Here the formulation of insulin particles is studied in detail and it is shown that particles consisting of high molecular weight protein (catalase) can also be prepared. In this context, the synthesis of CaCO3 templates with controlled size, the mechanism of the protein microparticle formation and mechanical properties of the microparticles are discussed. For the first time, the fabrication of mesoporous monodispersed CaCO3 microtemplates with identical porocity but tuned diameter from 3 to 20 μm is demonstrated. The protein particle diameter can be adjusted by choosing the appropriate template size that is critical for successful pulmonary delivery of insulin. As a first step towards insulin delivery, the in vitro release of insulin at physiological conditions is studied. 相似文献
87.
88.
89.
90.
Windhofer Karina Kari Alexander Prenninger Klaus Lange Stephan 《Forschung im Ingenieurwesen》2021,85(2):583-595
Forschung im Ingenieurwesen - Wind turbine noise used to be dominated by aerodynamic blade noise, effectively masking mechanical noise, originating from the drivetrain. Successful blade noise... 相似文献