全文获取类型
收费全文 | 1465篇 |
免费 | 26篇 |
专业分类
电工技术 | 17篇 |
综合类 | 2篇 |
化学工业 | 117篇 |
金属工艺 | 21篇 |
机械仪表 | 69篇 |
建筑科学 | 63篇 |
能源动力 | 14篇 |
轻工业 | 141篇 |
水利工程 | 20篇 |
石油天然气 | 2篇 |
无线电 | 133篇 |
一般工业技术 | 210篇 |
冶金工业 | 511篇 |
原子能技术 | 8篇 |
自动化技术 | 163篇 |
出版年
2021年 | 16篇 |
2020年 | 10篇 |
2019年 | 20篇 |
2018年 | 18篇 |
2017年 | 14篇 |
2016年 | 17篇 |
2015年 | 10篇 |
2014年 | 20篇 |
2013年 | 52篇 |
2012年 | 41篇 |
2011年 | 42篇 |
2010年 | 39篇 |
2009年 | 42篇 |
2008年 | 58篇 |
2007年 | 57篇 |
2006年 | 44篇 |
2005年 | 41篇 |
2004年 | 25篇 |
2003年 | 36篇 |
2002年 | 27篇 |
2001年 | 24篇 |
2000年 | 20篇 |
1999年 | 29篇 |
1998年 | 125篇 |
1997年 | 88篇 |
1996年 | 71篇 |
1995年 | 34篇 |
1994年 | 49篇 |
1993年 | 31篇 |
1992年 | 22篇 |
1991年 | 11篇 |
1990年 | 25篇 |
1989年 | 23篇 |
1988年 | 14篇 |
1987年 | 20篇 |
1986年 | 23篇 |
1985年 | 18篇 |
1984年 | 19篇 |
1983年 | 17篇 |
1982年 | 11篇 |
1981年 | 11篇 |
1980年 | 17篇 |
1979年 | 12篇 |
1978年 | 12篇 |
1977年 | 16篇 |
1976年 | 36篇 |
1975年 | 11篇 |
1974年 | 15篇 |
1973年 | 16篇 |
1968年 | 9篇 |
排序方式: 共有1491条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Understanding interactions between functionalized gold nanoparticles (NPs) and lipid bilayers is essential for biomedical applications. Experiments have shown that NPs that are stable in solution can assemble into clusters when adsorbed to a lipid bilayer, suggesting that bilayer-mediated interactions facilitate assembly. In this work, we use coarse-grained molecular dynamics simulations to study bilayer-mediated interactions between NPs adsorbed to single- and multicomponent lipid bilayers. We perform unbiased simulations and umbrella sampling calculations using an implicit solvent force field to determine the thermodynamic contributions to assembly. We show that bilayer-mediated interactions drive the assembly of NPs into linear aggregates on liquid-disordered bilayers, which we attribute to a reduction in bilayer curvature. Similar bilayer-mediated interactions induce the alignment of NP clusters with phase boundaries in phase-separated bilayers. Together, these simulation results provide new physical insight into the balance of forces that dictate the assembly of charged NPs at multicomponent lipid bilayer interfaces. 相似文献
5.
6.
ABSTRACT A series of batch contact tests were conducted to evaluate the exchange behavior of Ba, Ca, Pb, and Sr onto crystalline silicotitanate (CST) in support of an expedited Cs removal and pretreatment system at the Hanford site. Binary Na/M2+ and ternary Na/Cs/M2+ isotherms were generated to understand selectivity, capacity, and competitive impact of each analyte on Cs uptake from a simple 1 M NaOH/4.6 M NaNO3 simulant. Analyte loading from a 0.1 M NaOH/5.5 M NaNO3 simulant was assessed to determine the effect of hydroxide concentration on binary Na/M2+ isotherms. Results from binary and ternary isotherms indicated that Group II metals Ca, Sr, and Ba (and Pb) do not impact CST performance toward Cs removal at concentrations expected in Hanford tank-waste supernate. 相似文献
7.
Ali Sayir Marie-Hélène Berger Tyson C. Back Jonathan Mackey 《Journal of the American Ceramic Society》2021,104(11):5750-5763
Electron emission characteristic, electrical conductivity of polycrystalline mayenite (12CaO·7Al2O3) electride, formation of [Ca24Al28O64]4+(e−)4 framework as a function of phase content, and microstructure have been investigated. The mayenite microstructure was investigated using high-resolution transmission microscopy which revealed the type cage structure of 12CaO·7Al2O3 partially filled by extra-framework oxygen ions. Incorporation of electrons by means of carbon ion template 12CaO·7Al2O3 produces complex structure, and an incomplete ion template 12CaO·7Al2O3 structure consisting of mixture of a [Ca24Al28O64]4+(e−)4 and [Ca24Al28O64]4+(O2−)2 framework had a direct effect on the electron emission. Surface chemistry and stability of the 12CaO·7Al2O3 electride have been studied using x-ray photoelectron spectroscopy. The work function of phase pure 12CaO·7Al2O3 electride was determined from direct thermionic emission data and compared to the measurement from ultraviolet photoelectron spectroscopy (UPS). Depending on the extent of ion template of 12CaO·7Al2O3 structure, a work function of 0.9–1.2 eV and 2.1–2.4 eV has been measured and thermionic emission initiating at 600°C. 相似文献
8.
As outlined in compression therapy literature, the performance of a compression textile can be characterized by its stiffness and interface pressure. In this study, an indirect approach for measuring pressure from a set of compression bandages and hosiery was developed, from which rigidity (EI) values were determined, and tension–elongation curves and pressure-elongation data were calculated. The calculated pressure values were compared against PicoPress sensor readings measured on 10 participants. Results showed that the correlation between both approaches varied among bandage and hosiery samples. 相似文献
9.
Dr. Lalit N. Goswami Dr. Tyson J. Olds Dr. Terri G. Monk Dr. Quinn L. Johnson Dr. James P. Dilger Dr. Mohammed A. Shanawaz Dr. Satish S. Jalisatgi Dr. M. Frederick Hawthorne Dr. George R. Kracke 《ChemMedChem》2019,14(11):1108-1114
We synthesized a family of neuromuscular blocking agents (NMB) based on decamethonium, but containing a carborane cluster in the methylene chain between the two quaternary ammonium groups. The carborane cluster isomers o-NMB, m-NMB, and p-NMB were tested in animals for neuromuscular block and compared with agents used clinically: rocuronium and decamethonium. All three isomers caused reversible muscle weakness in mice as determined by grip strength and inverted screen tests, with a potency rank of p-NMB > rocuronium > decamethonium > m-NMB > o-NMB. The mechanism of action of the compounds was determined by using the in vitro rat phrenic nerve hemi-diaphragm preparation and electrophysiologic measurements in cells. Neostigmine reversed hemi-diaphragm weakness caused by the three isomers and rocuronium, but not succinylcholine. In electrophysiologic recordings of currents through acetylcholine receptor channels, the carborane compounds did not activate channel activity but did inhibit channel activation by acetylcholine. These results demonstrate that the carborane neuromuscular blocking agents are non-depolarizers in contrast to the depolarizing action of the parent compound. 相似文献
10.
Cardiovascular disease is the leading cause of mortality worldwide. Therefore, new research strategies for the treatment of cardiovascular disease are required. Previously, extracellular matrices (ECMs) have been used alongside polymers to generate hybrid bioscaffolds. Herein, we propose combining aortic ECMs with a polycaprolactone electrospun scaffold and biomechanically evaluating the scaffolds. We electrospun three scaffolds with varying ECM concentrations and found that increasing the ECM concentration leads to decreased stiffness at low strains, increased elasticity at high strain, reduction in failure strain, and an increase in yield strength. We also noted a decrease in water droplet contact angle with the increasing ECM concentration. Furthermore, we found that all three scaffolds were capable of maintaining human umbilical vein endothelial cell attachment and survival. These findings show the wide spectrum of mechanical properties that can be achieved through the addition of different concentrations of ECM into the fibers. © 2019 The Authors. Journal of Applied Polymer Science published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48181. 相似文献