全文获取类型
收费全文 | 711篇 |
免费 | 85篇 |
专业分类
电工技术 | 3篇 |
综合类 | 3篇 |
化学工业 | 160篇 |
金属工艺 | 16篇 |
机械仪表 | 13篇 |
建筑科学 | 30篇 |
矿业工程 | 1篇 |
能源动力 | 43篇 |
轻工业 | 53篇 |
水利工程 | 12篇 |
石油天然气 | 2篇 |
无线电 | 51篇 |
一般工业技术 | 189篇 |
冶金工业 | 133篇 |
原子能技术 | 6篇 |
自动化技术 | 81篇 |
出版年
2023年 | 15篇 |
2022年 | 16篇 |
2021年 | 27篇 |
2020年 | 26篇 |
2019年 | 27篇 |
2018年 | 44篇 |
2017年 | 34篇 |
2016年 | 40篇 |
2015年 | 22篇 |
2014年 | 44篇 |
2013年 | 51篇 |
2012年 | 70篇 |
2011年 | 61篇 |
2010年 | 47篇 |
2009年 | 31篇 |
2008年 | 29篇 |
2007年 | 32篇 |
2006年 | 23篇 |
2005年 | 18篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2001年 | 5篇 |
2000年 | 2篇 |
1999年 | 8篇 |
1998年 | 16篇 |
1997年 | 16篇 |
1996年 | 10篇 |
1995年 | 4篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1992年 | 8篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1975年 | 2篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1970年 | 3篇 |
1968年 | 1篇 |
排序方式: 共有796条查询结果,搜索用时 390 毫秒
21.
Kyle J. Sommers Brian S. Bentley Dr. Robert G. Carden Savannah J. Post Ryan A. Allen Renee C. Kontos Jacob W. Black Prof. William M. Wuest Prof. Kevin P. C. Minbiole 《ChemMedChem》2021,16(3):467-471
Inspired by the incorporation of metallocene functionalities into a variety of bioactive structures, particularly antimicrobial peptides, we endeavored to broaden the structural variety of quaternary ammonium compounds (QACs) by the incorporation of the ferrocene moiety. Accordingly, 23 ferrocene-containing mono- and bisQACs were prepared in high yields and tested for activity against a variety of bacteria, including Gram-negative strains and a panel of clinically isolated MRSA strains. Ferrocene QACs were shown to be effective antiseptics with some displaying single-digit micromolar activity against all bacteria tested, demonstrating yet another step in the expansion of structural variety of antiseptic QACs. 相似文献
22.
Methods are presented that allow for the automatic increase and preservation of symmetry during global optimization of crystal structures. This systematic building of symmetry allows for its incorporation into structure prediction simulations even when the space group information is not known a priori. It is shown that simulations that build and maintain symmetry converge much more rapidly to ground state crystal structures than when symmetry is ignored, allowing for the treatment of unit cells much larger than would otherwise be possible, especially when beginning from the P1 space group. 相似文献
23.
Kyle Strabala Shawn Meagher Charles Landais Laurent Delbreilh Mehrdad Negahban Jean‐Marc Saiter Joseph Turner Adam Ingram Roman Golovchak 《Polymer Engineering and Science》2014,54(4):794-804
We have studied the response of mechanically toughened and physically aged polycarbonate primarily using Charpy impact and ultrasonic wave speed measurements. The toughening was conducted through plastic compression on as‐received PC. The Charpy impact tests showed anisotropic toughening, both in the absorbed energy and in the mode of fracture. The amount of toughening with plastic compression, even though anisotropic, is centered around the response of annealed and quenched samples, which represent the response of an unaged PC. There was an anisotropic drop in the toughness of some samples with aging. The time of this drop was uncorrelated in the different directions and disappeared for the highly toughened samples. This transition was bimodal and statistically distributed between either a fully ductile or a fully brittle failure. As the samples were prepared in a manner to remove induced residual stresses, this drop in toughening may be associated with an intrinsic anisotropic thermal aging of the deformed material. POLYM. ENG. SCI., 54:794–804, 2014. © 2013 Society of Plastics Engineers 相似文献
24.
The progress made in accelerating simulations of fluid flow using GPUs, and the challenges that remain, are surveyed. The review first provides an introduction to GPU computing and programming, and discusses various considerations for improved performance. Case studies comparing the performance of CPU- and GPU-based solvers for the Laplace and incompressible Navier–Stokes equations are performed in order to demonstrate the potential improvement even with simple codes. Recent efforts to accelerate CFD simulations using GPUs are reviewed for laminar, turbulent, and reactive flow solvers. Also, GPU implementations of the lattice Boltzmann method are reviewed. Finally, recommendations for implementing CFD codes on GPUs are given and remaining challenges are discussed, such as the need to develop new strategies and redesign algorithms to enable GPU acceleration. 相似文献
25.
The 1992 Framework Convention on Climate Change created the basic international architecture for addressing climate change. That treaty was negotiated at a time when the research literature examining emissions mitigation and the role of energy technology was relatively limited. In the two subsequent decades a great deal has been learned. The problem of stabilizing the concentration of greenhouse gases in the atmosphere has proved far more difficult than envisioned in 1992 and the role of technology appears even more important when emissions mitigation strategies are co-developed in the context of multiple competing ends. 相似文献
26.
27.
具有内部同步、2A开关的36V LED驱动器LT3922,是一款紧凑、通用的LED驱动器。 相似文献
28.
Effects of plasma treatment on biocompatibility of poly[(L‐lactide)‐co‐(ϵ‐caprolactone)] and poly[(L‐lactide)‐co‐glycolide] electrospun nanofibrous membranes
下载免费PDF全文
![点击此处可从《Polymer International》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Pimwalan Techaikool Donraporn Daranarong Jutamas Kongsuk Dheerawan Boonyawan Nursyuhada Haron William S Harley Kyle A Thomson L John R Foster Winita Punyodom 《Polymer International》2017,66(11):1640-1650
Poly[(l ‐lactide)‐co ‐(? ‐caprolactone)] (PLCL) and poly[(l ‐lactide)‐co ‐glycolide] (PLGA) copolymers are widely used in neural guide tissue regeneration. In this research, the surface modification of their hydrophilicity was achieved using plasma treatment. Attachment and proliferation of olfactory ensheathing cells on treated electrospun membranes increased by 26 and 32%, respectively, compared to the untreated PLCL and PLGA counterparts. Cells cultivated on both the PLCL and PLGA membranes showed high viability (>95%) and healthy morphologies with no evidence of cytotoxic effects. Cells grown on treated electrospun fibres displayed significant increases in mitochondrial activity and reductions in membrane leakage when compared to untreated samples. The results suggested that plasma treatment of the surface of the polymers enhanced both cell viability and growth without incurring any cytotoxic effects. © 2017 Society of Chemical Industry 相似文献
29.
Temperature Stability of Lead‐Free Niobate Piezoceramics with Engineered Morphotropic Phase Boundary
下载免费PDF全文
![点击此处可从《Journal of the American Ceramic Society》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Ruiping Wang Ke Wang Fangzhou Yao Jing‐Feng Li Florian H. Schader Kyle G. Webber Wook Jo Jürgen Rödel 《Journal of the American Ceramic Society》2015,98(7):2177-2182
The temperature dependence of piezoelectric properties (direct piezoelectric coefficient d33, converse piezoelectric coefficient d33(E = 0), strain S and electromechanical coupling coefficient kp) for two niobate‐based lead‐free piezoceramics have been contrasted. 0.92(Na0.5K0.5)NbO3–0.02(Bi1/2Li1/2)TiO3–0.06BaZrO3 (6BZ/2BLT/92NKN) has a morphotropic phase boundary (MPB) between rhombohedral and tetragonal at room temperature and 0.92(Na0.5K0.5)NbO3–0.03(Bi1/2Li1/2)TiO3–0.05BaZrO3 (5BZ/3BLT/92NKN) features an MPB engineered to be located below room temperature. At 30°C, d33, d33(E = 0), S (at 2 kV/mm), and kp are 252 pC/N, 230 pm/V, 0.069%, 0.51 for 5BZ/3BLT/92NKN; and 348 pC/N, 380 pm/V, 0.106%, 0.57 for 6BZ/2BLT/92NKN, respectively. With increasing temperature, the piezoelectric properties decrease. At 200°C, d33, d33(E = 0), S (at 2 kV/mm), and kp are 170 pC/N, 160 pm/V, 0.059%, 0.36 for 5BZ/3BLT/92NKN; and 181 pC/N, 190 pm/V, 0.061%, 0.39 for 6BZ/2BLT/92NKN. It is found that the electromechanical coupling coefficient has a better temperature stability than the piezoelectric coefficient in the studied system due to a large temperature‐dependent compliance change. The results demonstrate that engineering an MPB is highly effective in tailoring temperature stability of piezoceramics. 相似文献
30.
Chad A. Maschinot Dr. Audrey R. Corman Dr. Albert M. DeBerardinis Prof. M. Kyle Hadden 《ChemMedChem》2016,11(7):679-686
Oxysterols (OHCs) are metabolic byproducts of cholesterol that are known to function as agonists of the Hedgehog (Hh) signaling pathway. Previously, we reported 23(S)‐hydroxycholesterol [23(S)‐OHC, 4 ] as a potent activator of Hh signaling with the ability to functionally differentiate mouse embryonic fibroblasts to an osteogenic fate. To obtain 23(S)‐OHC in quantities suitable for in vivo evaluation, we developed a revised synthetic route that decreases the number of steps and chromatographic purifications, and which also enhances the stereoselective nature of the synthesis. This new route also allows access to the C21 methyl group of the OHC scaffold, and several new analogues with varying stereochemistry at this location were evaluated for their ability to up‐regulate the Hh pathway. 相似文献