全文获取类型
收费全文 | 209篇 |
免费 | 22篇 |
专业分类
电工技术 | 4篇 |
化学工业 | 58篇 |
机械仪表 | 4篇 |
建筑科学 | 14篇 |
能源动力 | 8篇 |
轻工业 | 18篇 |
水利工程 | 2篇 |
无线电 | 15篇 |
一般工业技术 | 45篇 |
冶金工业 | 16篇 |
自动化技术 | 47篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 11篇 |
2020年 | 4篇 |
2019年 | 15篇 |
2018年 | 9篇 |
2017年 | 6篇 |
2016年 | 12篇 |
2015年 | 9篇 |
2014年 | 13篇 |
2013年 | 20篇 |
2012年 | 15篇 |
2011年 | 15篇 |
2010年 | 8篇 |
2009年 | 10篇 |
2008年 | 9篇 |
2007年 | 9篇 |
2006年 | 9篇 |
2005年 | 5篇 |
2004年 | 5篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 6篇 |
1997年 | 7篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1980年 | 2篇 |
排序方式: 共有231条查询结果,搜索用时 343 毫秒
31.
We discuss the potential benefits, requirements, and implementation challenges of a security-by-design approach in which an integrated development environment plugin assists software developers to write code that complies with secure coding guidelines. We discuss how such a plugin can enable a company's policy-setting security experts and developers to pass their knowledge on to each other more efficiently, and to let developers more effectively put that knowledge into practice. This is achieved by letting the team members develop customized rule sets that formalize coding guidelines and by letting the plugin check the compliance of code being written to those rule sets in real time, similar to an as-you-type spell checker. Upon detected violations, the plugin suggests options to quickly fix them and offers additional information for the developer. We share our experience with proof-of-concept designs and implementations rolled out in multiple companies, and present some future research and development directions. 相似文献
32.
We describe high-throughput experimentation of film synthesis by use of a linear tape transport system (similar to a web-coating system). Metal tape is fed continuously in a reel-to-reel transport system inside the vacuum deposition chamber. Ion-beam assisted deposition (IBAD) texturing is used to enable the growth of epitaxial films on flexible, polycrystalline metal tapes which further enhances the capability of this research. The tape that is continuously fed can be used as a sample itself, via the use of IBAD-textured templates on the tape, or can be a carrier of other smaller substrates (even nonflexible ones). Characterization of samples is done by means of in situ monitoring as well as ex situ sequential analysis. We utilize in situ reflection high-energy electron diffraction for high-throughput analysis of samples. Epitaxial films are deposited on heated samples by evaporation and by pulsed laser deposition. Here, we explain the techniques and the methodologies developed for this type of combinatorial experimentation and show some examples of the material research completed. 相似文献
33.
Florian Weyland Matias Acosta Malte Vögler Yoshitaka Ehara Jürgen Rödel Nikola Novak 《Journal of Materials Science》2018,53(13):9393-9400
The electric field–temperature phase diagrams of three bismuth sodium titanate-based relaxor ferroelectrics are reported, namely 0.94(Na1/2Bi1/2TiO3)–0.06(BaTiO3), 0.80(Na1/2Bi1/2TiO3)–0.20(K1/2Bi1/2TiO3) and 0.75(Na1/2Bi1/2TiO3)–0.25(SrTiO3). Relaxor behavior is demonstrated by temperature-dependent dielectric permittivity measurements in the unpoled and poled states, as well as by the field-induced phase transition into a ferroelectric phase from the relaxor phase. From temperature-dependent thermometry measurements, we identified the threshold electric field to induce the ferroelectric phase and obtained the released latent heat of the phase transition. We determined the nonergodic and ergodic relaxor phase temperature range based on the absence or presence of reversibility of the relaxor to ferroelectric transition. For all three compositions, the electric field–temperature phase diagram was constructed and a critical point was identified. The constructed electric field–temperature phase diagrams are useful to find optimum operational ranges of ferroelectrics and relaxors for electromechanical and electrocaloric applications. 相似文献
34.
Matthias Droste Antti Jrvenp Matias Jaskari Mykhaylo Motylenko Anja Weidner Pentti Karjalainen Horst Biermann 《Fatigue & Fracture of Engineering Materials & Structures》2021,44(1):43-62
Different grain sizes were created in a metastable 17Cr‐7Mn‐7Ni steel by martensite‐to‐austenite reversion at different temperatures using a laser beam. Two fully reverted material states obtained at 990°C and 780°C exhibited average grain sizes of 7.7 and 2.7 μm, respectively. The third microstructure (610°C) consisted of grains at different stages of recrystallization and deformed austenite. A hot‐pressed, coarse‐grained counterpart was studied for reference. The yield and tensile strengths increased with refined grain size, maintaining reasonable elongation except for the heterogeneous microstructure. Total strain‐controlled fatigue tests revealed increasing initial stress amplitudes but decreasing cyclic hardening and fatigue‐induced α′‐martensite formation with decreasing grain size. Fatigue life was slightly improved for the 2.7‐μm grain size. Contrary, the heterogeneous microstructure yielded an inferior lifetime, especially at high strain amplitudes. Examinations of the cyclically deformed microstructure showed that the characteristic deformation band structure was less pronounced in refined grains. 相似文献
35.
Maximilian Hrner Katrin Raute Barbara Hummel Josef Madl Guido Creusen Oliver S. Thomas Erik H. Christen Natascha Hotz Raphael J. Gübeli Raphael Engesser Balder Rebmann Jasmin Lauer Bernd Rolauffs Jens Timmer Wolfgang W. A. Schamel Jan Pruszak Winfried Rmer Matias D. Zurbriggen Christian Friedrich Andreas Walther Susana Minguet Ritwick Sawarkar Wilfried Weber 《Advanced materials (Deerfield Beach, Fla.)》2019,31(12)
36.
Maximilian Hrner Katrin Raute Barbara Hummel Josef Madl Guido Creusen Oliver S. Thomas Erik H. Christen Natascha Hotz Raphael J. Gübeli Raphael Engesser Balder Rebmann Jasmin Lauer Bernd Rolauffs Jens Timmer Wolfgang W. A. Schamel Jan Pruszak Winfried Rmer Matias D. Zurbriggen Christian Friedrich Andreas Walther Susana Minguet Ritwick Sawarkar Wilfried Weber 《Advanced materials (Deerfield Beach, Fla.)》2019,31(12)
Interrogation and control of cellular fate and function using optogenetics is providing revolutionary insights into biology. Optogenetic control of cells is achieved by coupling genetically encoded photoreceptors to cellular effectors and enables unprecedented spatiotemporal control of signaling processes. Here, a fast and reversibly switchable photoreceptor is used to tune the mechanical properties of polymer materials in a fully reversible, wavelength‐specific, and dose‐ and space‐controlled manner. By integrating engineered cyanobacterial phytochrome 1 into a poly(ethylene glycol) matrix, hydrogel materials responsive to light in the cell‐compatible red/far‐red spectrum are synthesized. These materials are applied to study in human mesenchymal stem cells how different mechanosignaling pathways respond to changing mechanical environments and to control the migration of primary immune cells in 3D. This optogenetics‐inspired matrix allows fundamental questions of how cells react to dynamic mechanical environments to be addressed. Further, remote control of such matrices can create new opportunities for tissue engineering or provide a basis for optically stimulated drug depots. 相似文献
37.
Influence of composition on the unipolar electric fatigue of Ba(Zr0.2Ti0.8)O3‐(Ba0.7Ca0.3)TiO3 lead‐free piezoceramics 下载免费PDF全文
Virginia Rojas Jurij Koruza Eric A. Patterson Matias Acosta Xijie Jiang Na Liu Christian Dietz Jürgen Rödel 《Journal of the American Ceramic Society》2017,100(10):4699-4709
The lead‐free (1?x)Ba(Zr0.2Ti0.8)O3‐x(Ba0.7Ca0.3)TiO3 system is considered as promising candidate for the replacement of lead‐based piezoceramics in actuation applications, during which electric fatigue is a major concern. This issue was addressed in this work, where the unipolar fatigue resistance of three (1?x)Ba(Zr0.2Ti0.8)O3‐x(Ba0.7Ca0.3)TiO3 compositions with different crystallographic structures (rhombohedral, orthorhombic, and tetragonal) was evaluated. Strain asymmetry and development of an internal bias field were observed in all compositions. The decrease in the remanent polarization and the large signal piezoelectric coefficient after 107 unipolar cycles was found to lie between 6%‐12% and 2%‐13%, respectively. The most pronounced fatigue was observed for the orthorhombic composition, which has the largest extrinsic contribution to strain. On the other hand, the best fatigue resistance was observed for the tetragonal composition, which has a predominantly intrinsic strain response. The correlation of fatigue resistance with strain mechanism was corroborated with determination of the Rayleigh parameters and changes in the domain morphology after cycling as confirmed by piezoresponse force microscopy. 相似文献
38.
39.
Dahlberg M Eklöf M Fredriksson P Jofre-Monseny J 《Urban studies (Edinburgh, Scotland)》2012,49(2):319-336
Using Swedish micro data, the paper examines the impact of local public services on community choice. The choice of community is modelled as a choice between a discrete set of alternatives. It is found that, given taxes, high spending on child care attracts migrants. Less conclusive results are obtained with respect to the role of spending on education and elderly care. High local taxes deter migrants. Relaxing the independence of the irrelevant alternatives assumption, by estimating a mixed logit model, has a significant impact on the results. 相似文献
40.
Ana Teresa SerraAna A. Matias Ana P.C. AlmeidaM.R. Bronze Paula M. Alves Hermínio C. de SousaCatarina M.M. Duarte 《The Journal of Supercritical Fluids》2011,55(3):1007-1013
In the last years, there has been a growing interest in the recovery of bioactive compounds from natural sources for the development of novel functional foods.In this study, natural extracts, previously obtained by fractioned high pressure extraction from “Saco” cherry culls, were characterized in terms of anticancer activity. The product derived from CO2:EtOH (90:10, v/v) extraction after a pre-treatment of raw material with supercritical CO2 during 1 h, exhibited the highest antiproliferative activity in human HT29 colon cancer cells. In addition, when compared with doxorubicin, cherry extracts induced cell cycle arrest in a different cell cycle checkpoint.In order to obtain extracts with enhanced antiproliferative activity, the extraction process was further explored. Using highly pure CO2 and EtOH 96% the inhibition of cancer cell growth was significantly enhanced by 16-fold. In addition, the incorporation of a conventional extraction step with MetOH or EtOH:H2O (50:50, v/v) prior to fractioned process allowed to obtain cherry extracts more concentrated in antiproliferative compounds. Perillyl alcohol present in cherry extracts was pointed to be one of the major responsible for anticancer properties of cherry extracts. 相似文献