全文获取类型
收费全文 | 1913篇 |
免费 | 128篇 |
专业分类
电工技术 | 11篇 |
化学工业 | 459篇 |
金属工艺 | 61篇 |
机械仪表 | 44篇 |
建筑科学 | 65篇 |
矿业工程 | 3篇 |
能源动力 | 34篇 |
轻工业 | 246篇 |
水利工程 | 14篇 |
石油天然气 | 9篇 |
无线电 | 178篇 |
一般工业技术 | 402篇 |
冶金工业 | 83篇 |
原子能技术 | 13篇 |
自动化技术 | 419篇 |
出版年
2024年 | 5篇 |
2023年 | 18篇 |
2022年 | 44篇 |
2021年 | 67篇 |
2020年 | 49篇 |
2019年 | 50篇 |
2018年 | 72篇 |
2017年 | 80篇 |
2016年 | 94篇 |
2015年 | 75篇 |
2014年 | 90篇 |
2013年 | 140篇 |
2012年 | 126篇 |
2011年 | 165篇 |
2010年 | 119篇 |
2009年 | 102篇 |
2008年 | 118篇 |
2007年 | 72篇 |
2006年 | 90篇 |
2005年 | 67篇 |
2004年 | 40篇 |
2003年 | 42篇 |
2002年 | 41篇 |
2001年 | 12篇 |
2000年 | 24篇 |
1999年 | 21篇 |
1998年 | 23篇 |
1997年 | 27篇 |
1996年 | 16篇 |
1995年 | 13篇 |
1994年 | 13篇 |
1993年 | 11篇 |
1992年 | 8篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1987年 | 3篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1981年 | 5篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 5篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 4篇 |
1968年 | 2篇 |
1955年 | 3篇 |
1939年 | 2篇 |
排序方式: 共有2041条查询结果,搜索用时 15 毫秒
961.
Delphine Toulemon Mircea V. Rastei David Schmool José Sáiz Garitaonandia Luis Lezama Xavier Cattoën Sylvie Bégin‐Colin Benoit P. Pichon 《Advanced functional materials》2016,26(15):2454-2462
1D assemblies of magnetic nanoparticles are of great potential for designing novel nanostructured materials with enhanced collective magnetic properties. In that challenging context, a new assembly strategy is presented to prepare chains of magnetic nanoparticles that are well‐defined in structure and in spatial arrangement. The 1D assembly of iron oxide nanoparticles onto a substrate is controlled using “click” chemistry under an external magnetic field. Co‐aligned single nanoparticle chains separated by regular distances can be obtained by this strategy. The intrinsic high uniaxial anisotropy results in a strong enhancement of magnetic collective properties in comparison to 2D monolayers or isolated nanoparticles. In contrast to the intensively studied bundle chains of nanoparticles, the finely tuned chain structure reported here allows evidencing a first order intrachain dipolar interaction and a second order interchain magnetic coupling. This study offers new insights into the collective magnetic properties of highly anisotropic particulate assemblies which have been investigated by combining superconducting quantum interference device magnetometry, magnetic force microscopy, and ferromagnetic resonance. 相似文献
962.
José Antonio Reglero Ruiz Michel Vincent Noëlle Billon 《International Journal of Material Forming》2016,9(5):585-590
Microcellular Polypropylene (PP) was obtained using Chemical Blowing Agents (CBA) in a injection process combined with Gas Counter Pressure (GCP) and core-back expansion molding. Two different types of PP, neat and charged, were mixed with a fixed proportion of CBA and injected into a plate, obtaining structural foams with a foamed core and solid outer skins. After, the plate morphology is analyzed to evaluate the main morphological parameters, such as cell size and thickness of the outer skin. The results show that the type of CBA has a great influence on the cell size. Finally, low velocity plane compression tests were carried out in the structural foams at a fixed strain rate to obtain the Young’s modulus of the foamed core and also the whole structure, using some theoretical approaches to evaluate the effect of foam density in the obtained results. 相似文献
963.
964.
Hadrien Bériot Albert Prinn Gwénaël Gabard 《International journal for numerical methods in engineering》2016,106(3):213-240
Computational modeling remains key to the acoustic design of various applications, but it is constrained by the cost of solving large Helmholtz problems at high frequencies. This paper presents an efficient implementation of the high‐order finite element method (FEM) for tackling large‐scale engineering problems arising in acoustics. A key feature of the proposed method is the ability to select automatically the order of interpolation in each element so as to obtain a target accuracy while minimizing the cost. This is achieved using a simple local a priori error indicator. For simulations involving several frequencies, the use of hierarchical shape functions leads to an efficient strategy to accelerate the assembly of the finite element model. The intrinsic performance of the high‐order FEM for 3D Helmholtz problem is assessed, and an error indicator is devised to select the polynomial order in each element. A realistic 3D application is presented in detail to demonstrate the reduction in computational costs and the robustness of the a priori error indicator. For this test case, the proposed method accelerates the simulation by an order of magnitude and requires less than a quarter of the memory needed by the standard FEM. © 2016 The Authors. International Journal for Numerical Methods in Engineering published by John Wiley & Sons Ltd. 相似文献
965.
966.
967.
Roullin V. Gaëlle Callewaert Maïté Molinari Michaël Delavoie Franck Seconde Aurélie Andry Marie-Christine 《纳微快报(英文)》2010,2(4):247-255
Nano-Micro Letters - In this formulation study, biocompatible non steroidal anti-inflammatory (NSAIDs)-loaded nanoparticles were designed as models to be further integrated in a prosthesis surface... 相似文献
968.
Ri-T-DNA-transformed carrot roots were used for investigating sterol metabolism by the arbuscular mycorrhizal (AM) fungus
Glomus intraradices under three distinct experimental conditions: (i) a symbiotic stage (fungus still attached to the host roots); (ii) a detached
stage (fungus physically separated from the roots); and (iii) a germinating stage (germinating spores). In all three stages,
G. intraradices was found to contain a mixture of 24-alkylated sterols, with 24-methyl and 24-ethyl cholesterol as the main compounds, but
no ergosterol, the predominant sterol in most fungi. Feeding experiments with [1-14C]sodium acetate were performed to check the ability of the fungus to synthesize sterols. Whatever the experimental conditions,
G. intraradices was able to actively take up exogenous acetate and to incorporate it into sterols and their precursors. Our data provide
first evidence for de novo sterol synthesis by an AM fungus. 相似文献
969.
Stijn van der Veen Norhan Nady Maurice C. R. Franssen Han Zuilhof Remko M. Boom Tjakko Abee Karin Schroën 《应用聚合物科学杂志》2015,132(10)
The effect of enzyme‐catalyzed modification of poly(ethersulfone) (PES) on the adhesion and biofilm formation of two Listeria monocytogenes strains is evaluated under static and dynamic flow conditions. PES has been modified with gallic acid, ferulic acid and 4‐hydroxybenzoic acid. The surfaces modified with any of these compounds show up to 70% reduced adhesion of L. monocytogenes under static conditions and up to 95% under dynamic flow conditions compared with unmodified surfaces. Also, under static conditions the formation of biofilms is reduced by ~70%. These results indicate that the brush structures that are formed by the polymers on the PES surface directly influence the ability of microorganisms to interact with the surface, thereby reducing attachment and biofilm formation of L. monocytogenes. Based on these results, it is expected that enzyme‐catalyzed surface modification is a promising tool to reduce microbial adhesion and biofilm formation. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41576. 相似文献
970.
“Squalenoylcurcumin” Nanoassemblies as Water‐Dispersible Drug Candidates with Antileishmanial Activity 下载免费PDF全文
Dr. Zakaria Cheikh‐Ali Dr. Joachim Caron Dr. Sandrine Cojean Dr. Christian Bories Prof. Patrick Couvreur Prof. Philippe M. Loiseau Dr. Didier Desmaële Prof. Erwan Poupon Prof. Pierre Champy 《ChemMedChem》2015,10(2):411-418
Curcumin, a natural polyphenolic compound, showed antiparasitic potential, including trypanocidal and leishmanicidal activity, in several in vitro and in vivo models. The molecule is well tolerated in humans. However, it is insoluble in water and displays poor oral bioavailability as a result of low absorption. New derivatives of curcumin were prepared by esterification of one or two of its phenolic groups with 1,1′,2‐tris‐norsqualenic acid. These “squalenoylcurcumins” were formulated as water‐dispersible nanoassemblies of homogeneous size, and they proved to be stable. Squalenoylcurcumins were inactive against Trypanosoma brucei brucei trypomastigotes, even as nanoassemblies, in contrast with curcumin. However, against Leishmania donovani promastigotes, the activities of the squalenoylcurcumins and their nanoassemblies were enhanced relative to that of curcumin. In L. donovani axenic and intramacrophagic amastigotes, they showed activity in the range of miltefosine, with good selectivity indexes. In regard to their dispersibility in water and to the safety of curcumin, these nanoassemblies are promising candidates for preclinical study toward the treatment of visceral leishmaniasis. 相似文献