全文获取类型
| 收费全文 | 3341篇 |
| 免费 | 68篇 |
| 国内免费 | 5篇 |
专业分类
| 电工技术 | 49篇 |
| 综合类 | 17篇 |
| 化学工业 | 702篇 |
| 金属工艺 | 88篇 |
| 机械仪表 | 80篇 |
| 建筑科学 | 341篇 |
| 矿业工程 | 24篇 |
| 能源动力 | 108篇 |
| 轻工业 | 149篇 |
| 水利工程 | 30篇 |
| 石油天然气 | 2篇 |
| 无线电 | 259篇 |
| 一般工业技术 | 714篇 |
| 冶金工业 | 139篇 |
| 原子能技术 | 12篇 |
| 自动化技术 | 700篇 |
出版年
| 2024年 | 56篇 |
| 2023年 | 76篇 |
| 2022年 | 91篇 |
| 2021年 | 135篇 |
| 2020年 | 148篇 |
| 2019年 | 136篇 |
| 2018年 | 120篇 |
| 2017年 | 96篇 |
| 2016年 | 160篇 |
| 2015年 | 138篇 |
| 2014年 | 157篇 |
| 2013年 | 223篇 |
| 2012年 | 237篇 |
| 2011年 | 267篇 |
| 2010年 | 174篇 |
| 2009年 | 165篇 |
| 2008年 | 162篇 |
| 2007年 | 163篇 |
| 2006年 | 99篇 |
| 2005年 | 85篇 |
| 2004年 | 77篇 |
| 2003年 | 52篇 |
| 2002年 | 64篇 |
| 2001年 | 29篇 |
| 2000年 | 26篇 |
| 1999年 | 30篇 |
| 1998年 | 35篇 |
| 1997年 | 33篇 |
| 1996年 | 22篇 |
| 1995年 | 19篇 |
| 1994年 | 15篇 |
| 1993年 | 16篇 |
| 1992年 | 17篇 |
| 1991年 | 13篇 |
| 1990年 | 8篇 |
| 1989年 | 3篇 |
| 1988年 | 6篇 |
| 1986年 | 3篇 |
| 1985年 | 8篇 |
| 1984年 | 9篇 |
| 1983年 | 7篇 |
| 1981年 | 4篇 |
| 1980年 | 2篇 |
| 1979年 | 3篇 |
| 1978年 | 3篇 |
| 1977年 | 2篇 |
| 1976年 | 2篇 |
| 1975年 | 4篇 |
| 1972年 | 2篇 |
| 1961年 | 2篇 |
排序方式： 共有3414条查询结果，搜索用时 15 毫秒
91.
Huibin He Jan‐Erik Ostwaldt Christoph Hirschhuser Carsten Schmuck Jochen Niemeyer 《Small (Weinheim an der Bergstrasse, Germany)》2020,16(28)
The dual pH‐induced reversible self‐assembly (PIRSA) of Au‐nanoparticles (Au NPs) is reported, based on their decoration with the self‐complementary guanidiniocarbonyl pyrrole carboxylate zwitterion (GCPZ). The assembly of such functionalized Au NPs is found at neutral pH, based on supramolecular pairing of the GCPZ groups. The resulting self‐assembled system can be switched back to the disassembled state by addition of base or acid. Two predominant effects that contribute to the dual‐PIRSA of Au NPs are identified, namely the ionic hydrogen bonding between the GCPZ groups, but also a strong hydrophobic effect. The contribution of each interaction is depending on the concentration of GCPZ on NPs, which allows to control the self‐assembly state over a wide range of different water/solvent ratios. 相似文献
92.
Alessandra Leonhardt Csar Javier Lockhart de la Rosa Thomas Nuytten Luca Banszerus Stefanie Sergeant Vivek K. Mootheri Takashi Taniguchi Kenji Watanabe Christoph Stampfer Cedric Huyghebaert Stefan De Gendt 《Advanced Materials Interfaces》2020,7(18)
Defect characterization of 2D materials is a critical aspect for their successful integration in future electronic devices. Here, a simple characterization technique is proposed that opens a path for fast, non‐invasive, quality assessment of transition metal dichalcogenide layers, such as MoS2, and their interfaces. It relates to the correlation between substrate‐induced traps and the indirect‐to‐direct photoluminescence peak ratio. It is shown that the indirect peak is quenched when interfacial trap sites are present. A physical mechanism is proposed to explain the observations based on different recombination mechanisms. 相似文献
93.
94.
Jingjing Tian Jing Wang Qifan Xue Tianqi Niu Lei Yan Zonglong Zhu Ning Li Christoph J. Brabec Hin‐Lap Yip Yong Cao 《Advanced functional materials》2020,30(28)
Cesium‐based inorganic perovskites have recently attracted great research focus due to their excellent optoelectronic properties and thermal stability. However, the operational instability of all‐inorganic perovskites is still a main hindrance for the commercialization. Herein, a facile approach is reported to simultaneously enhance both the efficiency and long‐term stability for all‐inorganic CsPbI2.5Br0.5 perovskite solar cells via inducing excess lead iodide (PbI2) into the precursors. Comprehensive film and device characterizations are conducted to study the influences of excess PbI2 on the crystal quality, passivation effect, charge dynamics, and photovoltaic performance. It is found that excess PbI2 improves the crystallization process, producing high‐quality CsPbI2.5Br0.5 films with enlarged grain sizes, enhanced crystal orientation, and unchanged phase composition. The residual PbI2 at the grain boundaries also provides a passivation effect, which improves the optoelectronic properties and charge collection property in optimized devices, leading to a power conversion efficiency up to 17.1% with a high open‐circuit voltage of 1.25 V. More importantly, a remarkable long‐term operational stability is also achieved for the optimized CsPbI2.5Br0.5 solar cells, with less than 24% degradation drop at the maximum power point under continuous illumination for 420 h. 相似文献
95.
Evelyn Ploetz Andreas Zimpel Valentina Cauda David Bauer Don C. Lamb Christoph Haisch Stefan Zahler Angelika M. Vollmar Stefan Wuttke Hanna Engelke 《Advanced materials (Deerfield Beach, Fla.)》2020,32(19):1907267
Ion homeostasis is essential for cellular survival, and elevated concentrations of specific ions are used to start distinct forms of programmed cell death. However, investigating the influence of certain ions on cells in a controlled way has been hampered due to the tight regulation of ion import by cells. Here, it is shown that lipid-coated iron-based metal–organic framework nanoparticles are able to deliver and release high amounts of iron ions into cells. While high concentrations of iron often trigger ferroptosis, here, the released iron induces pyroptosis, a form of cell death involving the immune system. The iron release occurs only in slightly acidic extracellular environments restricting cell death to cells in acidic microenvironments and allowing for external control. The release mechanism is based on endocytosis facilitated by the lipid-coating followed by degradation of the nanoparticle in the lysosome via cysteine-mediated reduction, which is enhanced in slightly acidic extracellular environment. Thus, a new functionality of hybrid nanoparticles is demonstrated, which uses their nanoarchitecture to facilitate controlled ion delivery into cells. Based on the selectivity for acidic microenvironments, the described nanoparticles may also be used for immunotherapy: the nanoparticles may directly affect the primary tumor and the induced pyroptosis activates the immune system. 相似文献
96.
Christoph A. Spiegel Marc Hippler Alexander Münchinger Martin Bastmeyer Christopher Barner‐Kowollik Martin Wegener Eva Blasco 《Advanced functional materials》2020,30(26)
3D printing of adaptive and dynamic structures, also known as 4D printing, is one of the key challenges in contemporary materials science. The additional dimension refers to the ability of 3D printed structures to change their properties—for example, shape—over time in a controlled fashion as the result of external stimulation. Within the last years, significant efforts have been undertaken in the development of new responsive materials for printing at the macroscale. However, 4D printing at the microscale is still in its early stages. Thus, this progress report will focus on emerging materials for 4D printing at the microscale as well as their challenges and potential applications. Hydrogels and liquid crystalline and composite materials have been identified as the main classes of materials representing the state of the art of the growing field. For each type of material, the challenges and critical barriers in the material design and their performance in 4D microprinting are discussed. Importantly, further necessary strategies are proposed to overcome the limitations of the current approaches and move toward their application in fields such as biomedicine, microrobotics, or optics. 相似文献
97.
Prof. Dr.-Ing. Ulrike Kuhlmann Simon Bove Prof. Dr.-Ing. André Dürr Jakob Roth Dr. rer. nat. Ralf Steinhausen Dr. rer. nat. Christoph Pientschke Dr. rer. nat. Mario Kiel 《Stahlbau》2020,89(4):339-356
Fatigue of welded tubular K-joints made of circular hollow sections – standard-compliant design and weld quality In steel and composite bridges, in industry structures, cranes or in the offshore industry trusses of circular hollow sections (CHS) with welded tubular K-joints and thick-walled chords are subject to high fatigue loading. However, normative regulations have been lacking so far for a fatigue verification of these joints. This paper summarises the results of the FOSTA research project P1163 dealing with this topic. Two important aspects of the investigations were the extension of the application range to large-sized CHS (d > 500 mm) and the development of practice-oriented recommendations for fabrication and quality assurance of weld geometries. For this purpose, fatigue tests were conducted on large-sized CHS-joints (chord dimensions 660 mm × 60 mm) and on K-joints with specified weld root opening size and weld shape. These studies were accompanied by systematic ultrasonic tests with phased-array which also were used for the development of an inspection method for these complex weld geometries. Based on the results, a proposal for a DASt-Guideline was finally elaborated to promote the acceptance of trusses made of CHS with thick-walled chords in practice and also to take a first step towards standardization. 相似文献
98.
Nadia Gremer Dipl.-Ing. Univ.Prof. Dipl.-Ing. Dr. techn. Christoph Adam Dipl.-Ing. Dr. techn. Lukas Moschen Ricardo A. Medina 《Stahlbau》2020,89(1):4-15
Influence of damping modelling on the acceleration response of an earthquake-excited steel frame structure As part of a case study, this paper deals with the effect of different damping approaches on the computed acceleration response of a planar, regular, elastic steel frame under earthquake excitation. In this study, not only the amplification of the horizontal ground acceleration, as is usual in earthquake engineering, but also the amplification of the vertical ground acceleration is considered. It is shown that Rayleigh damping used in accordance with engineering and scientific practice, leads to a minor amplification of the vertical ground acceleration only because damping of the vertical modes is too large compared to the lateral modes. This explains the erroneous assumption that the amplification of the vertical ground acceleration is negligible. In contrast, Rayleigh damping based on effective vertical mass participation overestimates both horizontal and vertical structural acceleration. The implementation of the inherent damping in the computational model in the form of modal damping, however, leads to a realistic computational prediction of the acceleration response in both directions. 相似文献
99.
Current developments and construction techniques for glass façades All-glass constructions are both reduced and complex. Design, engineering, structural planning, logistics, production and assembly are closely linked in order to constantly push the limits of what is possible. But not only projects in which glass plays a statically supporting role are among the highlights. The design requirements of steel-and-glass structures are also becoming increasingly challenging and complex. The diversity of glass in the building industry will be demonstrated by means of a few project examples. For example the all-glass project ICONSIAM. In 2018, Bangkok's skyline was given a 750 000 m2 landmark on the Chao Phraya river with the luxury department store ICONSIAM. The design by Urban Architects included a “giant showcase window” extending over three storeys, which captivates with its transparency, minimalist detail solutions and a special design language. The shape of the 5 300 m2 façade was geometrically sophisticated: due to the onside conditions the glass façade was suspended from the ceiling, with the glass panes inclined in two directions and arranged in a zigzag pattern. The total height of the all-glass façade is 24 m. This and other practical examples show how complex all-glass constructions are; but how they can be realized in the highest quality using innovative techniques and construction principles. 相似文献
100.
Development of a virtual reality environment for interactive thermal room simulation This article describes an approach in which the modeling and simulation process for the indoor climate of buildings takes place entirely in a virtual reality (VR) environment. In this way, the simulation expert is immersively involved with regard to the spatial design, spatial perception and interaction with the spatial model. The simulated indoor climate resulting from the interactions and other variables such as energy demands are visualized in the VR environment as a feedback to the user. To implement the described approach in terms of software, the Modelica tool Dymola was integrated with the game engine Unity to form a complete system, with bidirectional data exchange taking place between the two programs. The building model of the Modelica library BuildingSystems forms the basis of the building physics calculations in Dymola. In Unity, a head-mounted display was integrated to implement the VR simulation environment, and the two modes ”modeling“ and ”simulation“ were prototypically implemented and evaluated in a simulation scenario. 相似文献