全文获取类型
收费全文 | 686篇 |
免费 | 37篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 13篇 |
化学工业 | 245篇 |
金属工艺 | 15篇 |
机械仪表 | 16篇 |
建筑科学 | 32篇 |
能源动力 | 18篇 |
轻工业 | 60篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 72篇 |
一般工业技术 | 115篇 |
冶金工业 | 9篇 |
原子能技术 | 9篇 |
自动化技术 | 119篇 |
出版年
2024年 | 1篇 |
2023年 | 15篇 |
2022年 | 47篇 |
2021年 | 43篇 |
2020年 | 23篇 |
2019年 | 20篇 |
2018年 | 27篇 |
2017年 | 25篇 |
2016年 | 31篇 |
2015年 | 27篇 |
2014年 | 31篇 |
2013年 | 56篇 |
2012年 | 38篇 |
2011年 | 55篇 |
2010年 | 34篇 |
2009年 | 42篇 |
2008年 | 35篇 |
2007年 | 35篇 |
2006年 | 25篇 |
2005年 | 21篇 |
2004年 | 20篇 |
2003年 | 19篇 |
2002年 | 7篇 |
2001年 | 5篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 4篇 |
1995年 | 2篇 |
1994年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有725条查询结果,搜索用时 62 毫秒
71.
Marco Artini Gianluca Vrenna Marika Trecca Vanessa Tuccio Guarna Assanti Ersilia Vita Fiscarelli Rosanna Papa Laura Selan 《International journal of molecular sciences》2022,23(20)
Pseudomonas aeruginosa is frequently involved in cystic fibrosis (CF) airway infections. Biofilm, motility, production of toxins and the invasion of host cells are different factors that increase P. aeruginosa’s virulence. The sessile phenotype offers protection to bacterial cells and resistance to antimicrobials and host immune attacks. Motility also contributes to bacterial colonization of surfaces and, consequently, to biofilm formation. Furthermore, the ability to adhere is the prelude for the internalization into lung cells, a common immune evasion mechanism used by most intracellular bacteria, such as P. aeruginosa. In previous studies we evaluated the activity of metalloprotease serratiopeptidase (SPEP) in impairing virulence-related properties in Gram-positive bacteria. This work aimed to investigate SPEP’s effects on different physiological aspects related to the virulence of P. aeruginosa isolated from CF patients, such as biofilm production, pyoverdine and pyocyanin production and invasion in alveolar epithelial cells. Obtained results showed that SPEP was able to impair the attachment to inert surfaces as well as adhesion/invasion of eukaryotic cells. Conversely, SPEP’s effect on pyocyanin and pyoverdine production was strongly strain-dependent, with an increase and/or a decrease of their production. Moreover, SPEP seemed to increase swarming motility and staphylolytic protease production. Our results suggest that a large number of clinical strains should be studied in-depth before drawing definitive conclusions. Why different strains sometimes react in opposing ways to a specific treatment is of great interest and will be the object of future studies. Therefore, SPEP affects P. aeruginosa’s physiology by differently acting on several bacterial factors related to its virulence. 相似文献
72.
In the paper the microstructural phenomena in terms of average grain size occurring in friction stir welding (FSW) processes are focused. A neural network was linked to a finite element model (FEM) of the process to predict the average grain size values. The utilized net was trained starting from experimental data and numerical results of butt joints and then tested on further butt, lap and T-joints. The obtained results show the capability of the AI technique in conjunction with the FE tool to predict the final microstructure in the FSW joints. 相似文献
73.
Sara Gnavi Benedetta Elena Fornasari Chiara Tonda-Turo Rossella Laurano Marco Zanetti Gianluca Ciardelli Stefano Geuna 《International journal of molecular sciences》2015,16(6):12925-12942
Electrospun fibrous substrates mimicking extracellular matrices can be prepared by electrospinning, yielding aligned fibrous matrices as internal fillers to manufacture artificial nerves. Gelatin aligned nano-fibers were prepared by electrospinning after tuning the collector rotation speed. The effect of alignment on cell adhesion and proliferation was tested in vitro using primary cultures, the Schwann cell line, RT4-D6P2T, and the sensory neuron-like cell line, 50B11. Cell adhesion and proliferation were assessed by quantifying at several time-points. Aligned nano-fibers reduced adhesion and proliferation rate compared with random fibers. Schwann cell morphology and organization were investigated by immunostaining of the cytoskeleton. Cells were elongated with their longitudinal body parallel to the aligned fibers. B5011 neuron-like cells were aligned and had parallel axon growth when cultured on the aligned gelatin fibers. The data show that the alignment of electrospun gelatin fibers can modulate Schwann cells and axon organization in vitro, suggesting that this substrate shows promise as an internal filler for the design of artificial nerves for peripheral nerve reconstruction. 相似文献
74.
Maurizio Martina Guido Masera Gianluca Piccinini Maurizio Zamboni 《The Journal of VLSI Signal Processing》2003,35(2):137-153
This paper proposes two JPEG 2000 compliant architectures: one for DWT (Discrete Wavelet Transform) and one for IWT (Integer Wavelet Transform) implementation. First of all some theoretical issues about DWT and IWT are discussed, then, starting from transforms characteristics, the architectures are presented showing both performance and cost. In the literature many DWT architectures have been proposed; our implementation is a new architecture that computes the DWT using filters of interest for the forthcoming JPEG 2000 standard. Moreover, we propose a Lifting Scheme based architecture for IWT, JPEG 2000 compliant too. The proposed architectures are able to support real-time streams: the DWT one, which is made of 20,000 cells, with an input throughput of 160 Msamples per second and a clock frequency of 160 MHz, the IWT one, consisting of 50,000 cells, with an input throughput of 4.5 Msamples per second and an internal clock frequency of 108 MHz. 相似文献
75.
Gianluca Bianchini Marcello Crucianelli Claudia Crestini Raffaele Saladino 《Topics in Catalysis》2006,40(1-4):221-227
Polymer-supported methyltrioxorhenium (MTO) compounds are shown to act as efficient and selective catalysts for the oxy-functionalization
of C–H bonds in representative hydrocarbon derivatives (leading to the corresponding alcohols or ketones), using H2O2 as oxidant. The different supports used for the heterogenation of MTO, such as poly(4-vinylpyridine), poly(4-vinylpyridine)-N-oxide and polystyrene resins, all showed different catalytic behaviour in terms of substrate conversion and product yield,
depending on the experimental conditions used. It is noteworthy that the novel heterogeneous catalysts were found to be stable,
it being possible to effect their recover and recycle at least five times without appreciable loss of activity. 相似文献
76.
Gianluca Pedrina 《电子设计应用》2005,(9):103-104
引言在家用电器、供暖、通风、空调)和汽车应用中,DC无刷电机及其驱动器的使用率越来越高。造成这种现象的原因是其所拥有的高效、可靠、紧凑、低维护等级以及低噪声等优点,而这些都将转化为成本的节省。家用电器常常运用传统技术,比如带有起动电容的AC磁阻单相电机和通用式电机。所有这些解决方案采用AC供电方式,工作速度都是恒定不变的,而且并未关注效率。如今,客户所提出的要求越来越多,他们渴望拥有改良型功率分配方案、更加优越的性能以及更低的噪声电平:传统技术的局限性正日益凸显出来。同时,市场竞争对能量-效率比提出了新的更高… 相似文献
77.
78.
Monti G De Napoli L Mainolfi P Barone R Guida M Marino G Amoresano A 《Analytical chemistry》2005,77(8):2587-2594
Monitoring food quality is a critical task for analytical chemistry and an important way to preserve human health. Fish is a valuable source of highly digestible proteins and contains large amounts of polyunsaturated fatty acids and fat-soluble vitamins. Since the world's wild fish stocks are limited, farmed fish is nowadays proposed as an alternative to consumers. It is now emerging that the fish muscle protein content is assuming great importance from an aquaculture perspective. Many data have been collected on the physiology and biochemistry of fish muscle, but few proteomic studies are available on farmed fish. Application of proteomics to aquaculture may play a key role in the development of new farming strategies. In this paper, a proteomic approach based on SDS-PAGE separation of proteins, in situ protein hydrolysis, de novo sequencing of peptides by MALDI and ESI MS(2), protein identification, and relative quantitation of protein by denaturing capillary electrophoresis was coupled with the determination of fatty acids and metal ions content by GM-MS and ICPMS in farmed and wild sea bass filet. Our results show that aquaculture could induce significant chemical and biochemical differences in fish muscle that may have an impact on food quality. 相似文献
79.
Structure control, coating properties, and durability of fluorinated acrylic-based polymers 总被引:1,自引:0,他引:1
Valter Castelvetro Mauro Aglietto Francesco Ciardelli Oscar Chiantore Massimo Lazzari Lucia Toniolo 《Journal of Coatings Technology》2002,74(928):57-66
Fluorinated acrylates were employed for the synthesis of conventional, side-chain fluorinated, fully acrylic random copolymers,
and of more unusual hybrid copolymers with vinyl ethers. The latter can feature alternating structure and peculiar material
properties associated with fluorine or fluorinated groups substitution onto the polymer backbone. Improved efficacy and durability
of the resulting coating, highly desirable for the consolidation and protection of highly valued works of art, was achieved
through a systematic approach involving a detailed study of their photodegradation behavior, and extensive testing of protection
efficacy upon application onto micro-and macroporous stone substrates of different chemical composition and morphology.
Presented on behalf of FATIPEC (AITIVA) at the 78th Annual Meeting of the FSCT in Chicago, IL on October 16–20, 2000.
Dipartimento di Chimica e Chimica Industriale, Via Risorgimento 35, 56126 Pisa, Italy.
Dipartimento di Chimica IFM, via Pietro Giuria 7, 10125 Torino, Italy.
Piazza Leonardo da Vinci 32, 20133 Milano, Italy, Lucia. 相似文献
80.
Filippo Romanato Husen Kartasasmita Kang Kwang Hong Lee Gianluca Ruffato Mauro Prasciolu Chee Cheong Wong 《Microelectronic Engineering》2009,86(4-6):573-576
Nonlinear processes involved in the manufacture of nominally sinusoidal surface relief diffraction gratings generated by interference lithography can introduce distortions into the profile of these surfaces. Such distortions may dramatically affect both the specular reflectivity and diffracted efficiencies from such a surface [H. Raether, Phys. Thin Film 9 (1977) 145–261]. We shall consider in particular the case of metallic gratings used to investigate plasmonic effects that can be engineered for bio-sensing applications. To investigate these effects, interference lithography (IL) has been used for the generation of profile controlled sinusoidal plasmonic crystals. IL exposure contrast study has been performed to control the amplitude oscillation and the surface roughness quality. Bi-metallic layer of silver and gold have been systematically deposited with different film thicknesses. A comprehensive numerical model that studies the optical coupling to surface plasmon polaritons on Ag/Au gratings has been undertaken for the simulation of the reflectivity and azimuthal angle dependence [Z. Chen, I.R. Hooper, J.R. Sambles, J. Opt. A: Pure Appl. Opt. 10 (1) (2008) 015007]. This computation illustrates the sensitivity of individual features to specific harmonic components of the surface, for surface plasmon resonances recorded in both the zeroth and higher diffracted orders. The roughness surface control after development and after bi-metallic evaporation strongly contributes to tighten the width of the reflectivity peak. Optimization process has shown that for an Ag (37 nm) and Au (7 nm) metallic bilayer, a semi-amplitude of 20 nm provides the best reflectivity. 相似文献