全文获取类型
| 收费全文 | 4906篇 |
| 免费 | 182篇 |
| 国内免费 | 8篇 |
专业分类
| 电工技术 | 60篇 |
| 综合类 | 8篇 |
| 化学工业 | 938篇 |
| 金属工艺 | 55篇 |
| 机械仪表 | 74篇 |
| 建筑科学 | 179篇 |
| 矿业工程 | 5篇 |
| 能源动力 | 162篇 |
| 轻工业 | 337篇 |
| 水利工程 | 61篇 |
| 石油天然气 | 36篇 |
| 无线电 | 431篇 |
| 一般工业技术 | 1227篇 |
| 冶金工业 | 579篇 |
| 原子能技术 | 13篇 |
| 自动化技术 | 931篇 |
出版年
| 2024年 | 56篇 |
| 2023年 | 68篇 |
| 2022年 | 96篇 |
| 2021年 | 153篇 |
| 2020年 | 141篇 |
| 2019年 | 151篇 |
| 2018年 | 126篇 |
| 2017年 | 137篇 |
| 2016年 | 169篇 |
| 2015年 | 134篇 |
| 2014年 | 188篇 |
| 2013年 | 331篇 |
| 2012年 | 309篇 |
| 2011年 | 384篇 |
| 2010年 | 295篇 |
| 2009年 | 281篇 |
| 2008年 | 306篇 |
| 2007年 | 243篇 |
| 2006年 | 214篇 |
| 2005年 | 185篇 |
| 2004年 | 152篇 |
| 2003年 | 133篇 |
| 2002年 | 128篇 |
| 2001年 | 65篇 |
| 2000年 | 60篇 |
| 1999年 | 59篇 |
| 1998年 | 43篇 |
| 1997年 | 42篇 |
| 1996年 | 46篇 |
| 1995年 | 40篇 |
| 1994年 | 38篇 |
| 1993年 | 34篇 |
| 1992年 | 37篇 |
| 1991年 | 20篇 |
| 1990年 | 26篇 |
| 1989年 | 13篇 |
| 1988年 | 13篇 |
| 1987年 | 27篇 |
| 1986年 | 15篇 |
| 1985年 | 28篇 |
| 1984年 | 13篇 |
| 1983年 | 6篇 |
| 1982年 | 12篇 |
| 1981年 | 20篇 |
| 1977年 | 5篇 |
| 1976年 | 8篇 |
| 1975年 | 7篇 |
| 1974年 | 5篇 |
| 1973年 | 6篇 |
| 1964年 | 4篇 |
排序方式： 共有5096条查询结果，搜索用时 15 毫秒
991.
Guo Yi Bankestrom Olle Bergua Roger Keller Jonathan Dunn Mark 《Forschung im Ingenieurwesen》2021,85(2):405-415
Forschung im Ingenieurwesen - Wear-related failures of spherical roller bearings in the main bearing position of three-point mount wind turbines have been higher than expected and can contribute to... 相似文献
992.
Yeon Sik Choi Jahyun Koo Young Joong Lee Geumbee Lee Raudel Avila Hanze Ying Jonathan Reeder Leonhard Hambitzer Kyungtaek Im Jungwon Kim Kyung‐Mi Lee Jianjun Cheng Yonggang Huang Seung‐Kyun Kang John A. Rogers 《Advanced functional materials》2020,30(31)
Bioresorbable electronic systems represent an emerging class of technology of interest due to their ability to dissolve, chemically degrade, disintegrate, and/or otherwise physically disappear harmlessly in biological environments, as the basis for temporary implants that avoid the need for secondary surgical extraction procedures. Polyanhydride‐based polymers can serve as hydrophobic encapsulation layers for such systems, as a subset of the broader field of transient electronics, where biodegradation eventually occurs by chain scission. Systematic experimental studies that involve immersion in phosphate‐buffered saline solution at various pH values and/or temperatures demonstrate that dissolution occurs through a surface erosion mechanism, with little swelling. The mechanical properties of this polymer are well suited for use in soft, flexible devices, where integration can occur through a mold‐based photopolymerization technique. Studies of the dependence of the polymer properties on monomer compositions and the rates of permeation on coating thicknesses reveal some of the underlying effects. Simple demonstrations illustrate the ability to sustain operation of underlying biodegradable electronic systems for durations between a few hours to a week during complete immersion in aqueous solutions that approximate physiological conditions. Systematic chemical, physical, and in vivo biological studies in animal models reveal no signs of toxicity or other adverse biological responses. 相似文献
993.
Marcus A. O&#x;Mara Sean P. Ogilvie Matthew J. Large Aline Amorim Graf Anne C. Sehnal Peter J. Lynch Jonathan P. Salvage Izabela Jurewicz Alice A. K. King Alan B. Dalton 《Advanced functional materials》2020,30(32)
Here, an approach is presented to incorporate graphene nanosheets into a silicone rubber matrix via solid stabilization of oil‐in‐water emulsions. These emulsions can be cured into discrete, graphene‐coated silicone balls or continuous, elastomeric films by controlling the degree of coalescence. The electromechanical properties of the resulting composites as a function of interdiffusion time and graphene loading level are characterized. With conductivities approaching 1 S m?1, elongation to break up to 160%, and a gauge factor of ≈20 in the low‐strain linear regime, small strains such as pulse can be accurately measured. At higher strains, the electromechanical response exhibits a robust exponential dependence, allowing accurate readout for higher strain movements such as chest motion and joint bending. The exponential gauge factor is found to be ≈20, independent of loading level and valid up to 80% strain; this consistent performance is due to the emulsion‐templated microstructure of the composites. The robust behavior may facilitate high‐strain sensing in the nonlinear regime using nanocomposites, where relative resistance change values in excess of 107 enable highly accurate bodily motion monitoring. 相似文献
994.
Jonathan M. Zuidema Courtney M. Dumont Joanna Wang Wyndham M. Batchelor Yi‐Sheng Lu Jinyoung Kang Alessandro Bertucci Noel M. Ziebarth Lonnie D. Shea Michael J. Sailor 《Advanced functional materials》2020,30(25)
Scaffolds made from biocompatible polymers provide physical cues to direct the extension of neurites and to encourage repair of damaged nerves. The inclusion of neurotrophic payloads in these scaffolds can substantially enhance regrowth and repair processes. However, many promising neurotrophic candidates are excluded from this approach due to incompatibilities with the polymer or with the polymer processing conditions. This work provides one solution to this problem by incorporating porous silicon nanoparticles (pSiNPs) that are preloaded with the therapeutic into a polymer scaffold during fabrication. The nanoparticle‐drug‐polymer hybrids are prepared in the form of oriented poly(lactic‐co‐glycolic acid) nanofiber scaffolds. Three different therapeutic payloads are tested: bpV(HOpic), a small molecule inhibitor of phosphatase and tensin homolog (PTEN); an RNA aptamer specific to tropomyosin‐related kinase receptor type B (TrkB); and the protein nerve growth factor (NGF). Each therapeutic is loaded using a loading chemistry that is optimized to slow the rate of release of these water‐soluble payloads. The drug‐loaded pSiNP‐nanofiber hybrids release approximately half of their TrkB aptamer, bpV(HOpic), or NGF payload in 2, 10, and >40 days, respectively. The nanofiber hybrids increase neurite extension relative to drug‐free control nanofibers in a dorsal root ganglion explant assay. 相似文献
995.
Zachary S. Parr Reem B. Rashid Bryan D. Paulsen Benjamin Poggi Ellasia Tan Mark Freeley Matteo Palma Isaac Abrahams Jonathan Rivnay Christian B. Nielsen 《Advanced Electronic Materials》2020,6(6)
A series of semiconducting small molecules with bithiophene or bis‐3,4‐ethylenedioxythiophene cores are designed and synthesized. The molecules display stable reversible oxidation in solution and can be reversibly oxidized in the solid state with aqueous electrolyte when functionalized with polar triethylene glycol side chains. Evidence of promising ion injection properties observed with cyclic voltammetry is complemented by strong electrochromism probed by spectroelectrochemistry. Blending these molecules with high molecular weight polyethylene oxide (PEO) is found to improve both ion injection and thin film stability. The molecules and their corresponding PEO blends are investigated as active layers in organic electrochemical transistors (OECTs). For the most promising molecule:polymer blend (P4E4:PEO), p‐type accumulation mode OECTs with µA drain currents, μS peak transconductances, and a µC* figure‐of‐merit value of 0.81 F V−1 cm−1 s−1 are obtained. 相似文献
996.
997.
Michael Pauley Christopher Mclean Jonathan H. Manton 《International Journal of Adaptive Control and Signal Processing》2020,34(7):813-838
A class of discrete-time random processes arising in engineering and econometrics applications consists of a linear state-space model whose parameters are modulated by the state of a finite-state Markov chain. Typical filtering approaches are collapsing methods, which approximate filtered distributions by mixtures of Gaussians, each Gaussian corresponding to one possibility of the recent history of the Markov chain, and particle methods. This article presents an alternative approach to filtering these processes based on keeping track of the values of the underlying filtered density and its characteristic function on grids. We prove that it has favorable convergence properties under certain assumptions. On the other hand, as a grid method, it suffers from the curse of dimensionality, and so is only suitable for low-dimensional systems. We compare our method to collapsing filters and a particle filter with examples, and find that it can outperform them on 1- and 2-dimensional problems, but loses its speed advantage on 3-dimensional systems. Meanwhile, our method has a proven theoretical convergence rate that is probably not achieved by collapsing and particle methods. 相似文献
998.
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
999.
Yan Sun Fei Yu Meisong Liao Juping Ma Xin Wang Dongbing He Weiqing Gao Jonathan Knight Lili Hu 《Journal of the American Ceramic Society》2020,103(12):6847-6859
In this work, we systematically study the spectroscopic properties of Tb3+/Dy3+ co-doped phosphate glasses in the visible spectral region and explore the sensitization role of Dy3+ in the enhancement of visible fluorescence of Tb3+ ions. Judd-Ofelt parameters Ω2 and Ω4/Ω6 of the phosphate glass as host for Tb3+ are calculated as 21.60 × 10-20 cm2 and 0.73, respectively, based on the measured spectral absorption. Multiple energy transfer (ET) routes from Dy3+ to Tb3+ and their efficiencies are characterized, and the enhanced fluorescence properties of Tb3+ are investigated, including the emission spectral strength and the spontaneous emission lifetime as functions of Dy3+ doping concentration. The efficient nonradiative ET processes between Dy3+ and Tb3+ allow a moderate concentration level of Tb3+ to achieve favorably stronger spectral absorption at blue and ultraviolet wavelengths. Tb3+/Dy3+ co-doped phosphate glass shows promising potential for phosphors and lasing operation at visible wavelengths. 相似文献
1000.
Dr. Elizabeth A. Love Afrah Sattikar Dr. Hannah Cook Kevin Gillen Dr. Jonathan M. Large Dr. Seema Patel Dr. David Matthews Dr. Andy Merritt 《Chembiochem : a European journal of chemical biology》2019,20(6):754-758
Antibody–drug conjugates (ADCs) are a growing class of therapeutics that harness the specificity of antibodies and the cell-killing potency of small-molecule drugs. Beyond cytotoxics, there are few examples of the application of an ADC approach to difficult drug discovery targets. Here, we present the initial development of a non-internalising ADC, with a view to selectively inhibiting an extracellular protein. Employing the wellinvestigated matrix metalloproteinase-9 (MMP-9) as our model, we adapted a broad-spectrum, nonselective MMP inhibitor for conjugation and linked this to a MMP-9-targeting antibody. The resulting ADC fully inhibits MMP-9, and ELISA results suggest antibody targeting can direct a nonselective inhibitor. 相似文献