全文获取类型
收费全文 | 803篇 |
免费 | 74篇 |
专业分类
电工技术 | 12篇 |
综合类 | 5篇 |
化学工业 | 213篇 |
金属工艺 | 16篇 |
机械仪表 | 5篇 |
建筑科学 | 50篇 |
矿业工程 | 2篇 |
能源动力 | 39篇 |
轻工业 | 29篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 106篇 |
一般工业技术 | 158篇 |
冶金工业 | 67篇 |
原子能技术 | 2篇 |
自动化技术 | 170篇 |
出版年
2024年 | 3篇 |
2023年 | 32篇 |
2022年 | 21篇 |
2021年 | 73篇 |
2020年 | 46篇 |
2019年 | 26篇 |
2018年 | 41篇 |
2017年 | 33篇 |
2016年 | 46篇 |
2015年 | 30篇 |
2014年 | 60篇 |
2013年 | 62篇 |
2012年 | 46篇 |
2011年 | 63篇 |
2010年 | 33篇 |
2009年 | 34篇 |
2008年 | 31篇 |
2007年 | 31篇 |
2006年 | 12篇 |
2005年 | 12篇 |
2004年 | 17篇 |
2003年 | 8篇 |
2002年 | 8篇 |
2001年 | 5篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 21篇 |
1997年 | 9篇 |
1996年 | 7篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1925年 | 1篇 |
1919年 | 1篇 |
排序方式: 共有877条查询结果,搜索用时 205 毫秒
851.
Mauricio Rodríguez Chialanza José Fabian Schneider Romina Keuchkerian Mariano Romero Ricardo Faccio Alvaro Olivera Heinkel Bentos Pereira 《Journal of the American Ceramic Society》2020,103(5):3126-3137
Oxyfluoride glass and glass-ceramics are being studied due to the possibility of their utilization in many applications, such as thermoluminescent dosimeters, optical fibers, fluorescent concentrators, and temperature sensors. In order to improve the properties of glass, they are often crystallized. For this crystallization to be effective, knowledge and control of the structure of the starting material is required. Much work was done on silicate glass; however, a great interest exists in obtaining these kinds of materials in other matrices such as germanates, phosphates, and borates. Here, we present a structural study of some oxyfluoride borate glass with different concentrations of PbF2 by means of Nuclear Magnetic Resonance (NMR), Raman, and Fourier Transform Infrared (FTIR) spectroscopies. We also analyzed glass-crystallization using Differential Scanning Calorimetry (DSC). The crystallization study was complemented with the use of Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction (SAED), for the purpose of identifying possible mechanisms of crystallization. Our results indicate, from the structural point of view, that the glass present groups with one or two BO4 species, such as diborate or pentaborate. The small variation in the BO4 fraction with the increase in PbF2 concentration would be an indication of the formation of F−BO3/2 species. Oxyfluoride borate glass containing BaO as a cation modifier and 30% PbF2 represents a good starting point for obtaining glass-ceramics with a narrow size distribution of BaF2 nanocrystals. We also propose that the possible mechanism for oxyfluoride borate glass crystallization started with a separation of phases. 相似文献
852.
M.Sc. Max Herbers M.Sc. Jan-Hauke Bartels Dipl.-Ing. Bertram Richter Dipl.-Ing. Fabian Collin M.Sc. Lisa Ulbrich M.Sc. Thamer Al-Zuriqat M.Sc. Carlos Chillón Geck M.Sc. Hubert Naraniecki Dipl.-Ing. Oliver Hahn Dr.-Ing. Frank Jesse Prof. Dr.-Ing. Kay Smarsly Prof. Dr.-Ing. Steffen Marx 《Beton- und Stahlbetonbau》2024,119(3):169-180
openLAB – A research bridge for developing a digital twin of bridges Within the IDA-KI project, a research bridge (openLAB) is being built and loaded up to the level of severe damage. This will be accompanied by extensive measurements and investigations, thus creating a unique database for the validation of damage detection and evaluation methods under real environmental conditions using a large-scale model. This article presents the project idea, the research bridge currently under construction, and the monitoring system installed at the bridge. The methods implemented for automated data analysis and fault detection in the monitoring data are presented and validated through load tests in the openLAB. First measurements recorded during the production process of the precast girders of the research bridge underline the potential of distributed fiber optic sensors for a monitoring from day one. The information gained from the construction and operation of the bridge is provided in a digital model. The conceptualization of the so-called “as maintained“ model and the data management will be presented. 相似文献
853.
Jaroslav Chlupac Roman Matejka Miroslav Konarik Robert Novotny Zuzana Simunkova Iveta Mrazova Ondrej Fabian Milan Zapletal Zdenek Pulda Jan Falk Lipensky Jana Stepanovska Karel Hanzalek Antonin Broz Tomas Novak Alena Lodererova Ludek Voska Theodor Adla Jiri Fronek Miroslav Rozkot Serhiy Forostyak Peter Kneppo Lucie Bacakova Jan Pirk 《International journal of molecular sciences》2022,23(6)
Background: Cardiovascular surgery is confronted by a lack of suitable materials for patch repair. Acellular animal tissues serve as an abundant source of promising biomaterials. The aim of our study was to explore the bio-integration of decellularized or recellularized pericardial matrices in vivo. Methods: Porcine (allograft) and ovine (heterograft, xenograft) pericardia were decellularized using 1% sodium dodecyl sulfate ((1) Allo-decel and (2) Xeno-decel). We used two cell types for pressure-stimulated recellularization in a bioreactor: autologous adipose tissue-derived stromal cells (ASCs) isolated from subcutaneous fat of pigs ((3) Allo-ASC and (4) Xeno-ASC) and allogeneic Wharton’s jelly mesenchymal stem cells (WJCs) ((5) Allo-WJC and (6) Xeno-WJC). These six experimental patches were implanted in porcine carotid arteries for one month. For comparison, we also implanted six types of control patches, namely, arterial or venous autografts, expanded polytetrafluoroethylene (ePTFE Propaten® Gore®), polyethylene terephthalate (PET Vascutek®), chemically stabilized bovine pericardium (XenoSure®), and detoxified porcine pericardium (BioIntegral® NoReact®). The grafts were evaluated through the use of flowmetry, angiography, and histological examination. Results: All grafts were well-integrated and patent with no signs of thrombosis, stenosis, or aneurysm. A histological analysis revealed that the arterial autograft resembled a native artery. All other control and experimental patches developed neo-adventitial inflammation (NAI) and neo-intimal hyperplasia (NIH), and the endothelial lining was present. NAI and NIH were most prominent on XenoSure® and Xeno-decel and least prominent on NoReact®. In xenografts, the degree of NIH developed in the following order: Xeno-decel > Xeno-ASC > Xeno-WJC. NAI and patch resorption increased in Allo-ASC and Xeno-ASC and decreased in Allo-WJC and Xeno-WJC. Conclusions: In our setting, pre-implant seeding with ASC or WJC had a modest impact on vascular patch remodeling. However, ASC increased the neo-adventitial inflammatory reaction and patch resorption, suggesting accelerated remodeling. WJC mitigated this response, as well as neo-intimal hyperplasia on xenografts, suggesting immunomodulatory properties. 相似文献
854.
The thermally initiated thiol-ene emulsion polymerization of diallyl phthalate (DAP) diene and ethylenedioxy diethanthiol (EDDT) dithiol monomers in batch and semibatch emulsion polymerization is investigated. The batch process leads to larger and broader particle sizes than when the polymerization is carried out in semibatch. The evolution of the particle size and the final particle size distribution indicate that the stability of the latexes is limited and, hence, aggregation phenomena occurred in both processes. In particular, the evolution of the particle size distribution (PSD) in the semibatch process indicates nucleation, growth, and aggregation occurring simultaneously that produced a bimodal particle size. When the diene monomer was changed to diallyl terephthalate (DATP), the semibatch polymerization yielded smaller particles and narrow distribution without any indication of aggregation. The partial substitution of the dithiol by a trithiol monomer that is substantially more water insoluble affected nucleation of the particles, yielding for both systems smaller particles. The polythioether polymers synthesized present low glass transition temperatures (~ −30/−40°C) and those containing the therephthalate yield crystalline films. The potential application of the polymers as pressure sensitive adhesives (PSAs) was preliminarily assessed. 相似文献
855.
Fabian Kraemer Michael Stähler Marcus Klein Matthias Oechsner 《Materialwissenschaft und Werkstofftechnik》2023,54(8):932-944
The fatigue behavior of bolted joints is critical to failure for many applications due to the high notch effect. Among other parameters, the life-time is based on the influence of the surface system, consisting of coating and lubricant. Intended to consider the surface system in the design and dimensioning process of bolted joints systematic experimental investigations are carried out for an exemplary selected basecoat and various lubricant systems. The basis is given by fatigue tests supported by selected methods of material analysis for the fractographic evaluation. A reproducible method to determine the crack initiation as well as the crack propagation has been developed for the evaluation of lubricant systems. 相似文献
856.
Zalila Faiez Korte Fabian Erbel Johannes Challita Stéphanie Grabowski Jens Merle Philippe 《Software and Systems Modeling》2023,22(3):871-889
Software and Systems Modeling - To tackle the cloud-provider lock-in, the open grid forum is developing the open cloud computing interface (OCCI), a standardized interface for managing any kind of... 相似文献
857.
Yi-Hsuan Chen Peter Lennartz Kun Ling Liu Yi-Chen Hsieh Felix Scharf Rayan Guerdelli Annika Buchheit Mariano Grünebaum Fabian Kempe Martin Winter Gunther Brunklaus 《Advanced functional materials》2023,33(32):2300501
To go beyond polyethylene oxide in lithium metal batteries, a hybrid polymer/oligomer cell design is presented, where an ester oligomer provides high ionic conductivity of 0.2 mS cm−1 at 40 °C within thicker composite cathodes with active mass loadings of up to 11 mg cm−2 (LiNbO3-coated) LiNi0.6Mn0.2Co0.2 (NMC622), while a 30 µm thin scaffold-supported polymer electrolyte affords mechanical stability. Corresponding discharge capacities of the hybrid cells exceed 170 mAh g−1 (11 mg cm−2) or 160 mAh g−1 (6 mg cm−2) at rates of either 0.1 or 0.25 C. Multilayer pouch cells are projected to enable energy densities of 235 Wh L−1 (6 mg cm−2) and even up to 356 Wh L−1 (11 mg cm−2), clearly superior to other reported polymer-based cell designs. Polyester electrolytes are environmentally benign and safer compared to common liquid electrolytes, while the straightforward synthesis and affordability of precursors render hybrid polyester electrolytes suitable candidates for future application in solid-state lithium metal batteries. 相似文献
858.
Event sequence visualization aids analysts in many domains to better understand and infer new insights from event data. Analysing behaviour before or after a certain event of interest is a common task in many scenarios. In this paper, we introduce, formally define, and position double trees as a domain-agnostic tree visualization approach for this task. The visualization shows the sequences that led to the event of interest as a tree on the left, and those that followed on the right. Moreover, our approach enables users to create selections based on event attributes to interactively compare the events and sequences along colour-coded categories. We integrate the double tree and category-based comparison into a user interface for event sequence analysis. In three application examples, we show a diverse set of scenarios, covering short and long time spans, non-spatial and spatial events, human and artificial actors, to demonstrate the general applicability of the approach. 相似文献
859.
J. Fabian 《Advanced Synthesis \u0026amp; Catalysis》1990,332(1):128-128
860.
Achim Mehlhorn Jürgen Fabian Nikolay Tyutyulkov Gottfried Olbrich Fritz Dietz 《Advanced Synthesis \u0026amp; Catalysis》1986,328(4):603-611
Ab initio SCF and semiempirical MINDO/3 and PPP/DCI calculations have been applied to substituted cyclopentamethines which formally resulted from cyclization of streptopentamethines in the α,α′-positions. These compounds exhibit a typical streptopolymethinic charge distribution of the carbon atoms along the cyclized chain, unique molecular geometries, extremely small energy gaps between the lowest excited states S1, T1 and the ground state S0 as well as large electron affinities. With respect to molecular geometry, spectral behaviour and electron affinity substituted cyclopentamethines are closely related to the antiaromatic cyclopentadienyl cation. Depending on the substitution pattern, the one or the other of the two Jahn-Teller distorted geometries of the antiaromatic C5H5⊕ appears to be frozen. 相似文献