全文获取类型
收费全文 | 2236篇 |
免费 | 108篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 18篇 |
化学工业 | 467篇 |
金属工艺 | 45篇 |
机械仪表 | 30篇 |
建筑科学 | 111篇 |
矿业工程 | 4篇 |
能源动力 | 41篇 |
轻工业 | 217篇 |
水利工程 | 17篇 |
石油天然气 | 3篇 |
无线电 | 161篇 |
一般工业技术 | 379篇 |
冶金工业 | 424篇 |
原子能技术 | 28篇 |
自动化技术 | 403篇 |
出版年
2023年 | 26篇 |
2022年 | 10篇 |
2021年 | 47篇 |
2020年 | 36篇 |
2019年 | 39篇 |
2018年 | 66篇 |
2017年 | 55篇 |
2016年 | 64篇 |
2015年 | 42篇 |
2014年 | 60篇 |
2013年 | 136篇 |
2012年 | 110篇 |
2011年 | 155篇 |
2010年 | 124篇 |
2009年 | 94篇 |
2008年 | 125篇 |
2007年 | 111篇 |
2006年 | 85篇 |
2005年 | 90篇 |
2004年 | 78篇 |
2003年 | 69篇 |
2002年 | 56篇 |
2001年 | 40篇 |
2000年 | 28篇 |
1999年 | 28篇 |
1998年 | 49篇 |
1997年 | 35篇 |
1996年 | 35篇 |
1995年 | 30篇 |
1994年 | 32篇 |
1993年 | 33篇 |
1992年 | 28篇 |
1991年 | 24篇 |
1990年 | 27篇 |
1989年 | 26篇 |
1988年 | 17篇 |
1987年 | 21篇 |
1986年 | 14篇 |
1985年 | 19篇 |
1984年 | 20篇 |
1983年 | 19篇 |
1982年 | 24篇 |
1981年 | 19篇 |
1980年 | 14篇 |
1979年 | 26篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1976年 | 6篇 |
1970年 | 5篇 |
1958年 | 5篇 |
排序方式: 共有2348条查询结果,搜索用时 203 毫秒
1.
Nikolay Kardjilov Ingo Manke Robin Woracek André Hilger John Banhart 《Materials Today》2018,21(6):652-672
Imaging techniques based on neutron beams are rapidly developing and have become versatile non-destructive analyzing tools in many research fields. Due to their intrinsic properties, neutrons differ strongly from electrons, protons or X-rays in terms of their interaction with matter: they penetrate deeply into most common metallic materials while they have a high sensitivity to light elements such as hydrogen, hydrogenous substances, or lithium. This makes neutrons perfectly suited probes for research on materials that are used for energy storage and conversion, e.g., batteries, hydrogen storage, fuel cells, etc. Moreover, their wave properties can be exploited to perform diffraction, phase-contrast and dark-field imaging experiments. Their magnetic moment allows for resolving magnetic properties in bulk samples. This review will focus on recent applications of neutron imaging techniques in both materials research and fundamental science illustrated by examples selected from different areas. 相似文献
2.
Cinzia Daraio Kristiaan Kerstens Thyago Nepomuceno Robin C. Sickles 《International Transactions in Operational Research》2020,27(2):709-738
This contribution is the first attempt to systematically review all empirical surveys that so far have been made available in the broad field of efficiency and productivity analysis using frontier estimation methodologies. We provide a systematic bibliometric review on the many empirical surveys in the field of efficiency and productivity analysis, the most relevant concepts, areas, overlaps, and potentials to explore from its introduction to the most recent surveys. We combine the United Nations’ International Standard Industrial Classification (ISIC) taxonomy for the economic activity with the Journal of Economic Literature (JEL) classification system to classify the empirical surveys and to identify the current gaps in the literature. In addition to the most relevant/generic potential areas for applications (according to the United Nation's ISIC), this methodology provides a cluster analysis with the most relevant concepts that have been considered so far (according to the JEL codes). This overview brings an interesting guide for future work to develop the whole field. 相似文献
3.
4.
Raheleh Nikonam M. Martin D. Pugh Robin A.L. Drew 《Journal of the European Ceramic Society》2019,39(4):915-927
In porous reaction bonded silicon nitride, whiskers normally grow in globular clusters as the dominant morphology and deteriorate the pore interconnectivity. However, the ceramic microstructure was significantly transformed with the addition of MgO; specifically, the morphology was modified to a combination of matte and hexagonal grains. Microstructural observation along with thermodynamic studies suggest that MgO interfered with the presence and nitridation of SiO(g). Consequently, rather than being involved in the whiskers’ formation, surface silica instead reacted with volatile MgO to form intermediate products. Through these reactions, whisker formation was blocked, and a porous interconnected structure formed which was confirmed by 3D tomography. After heat-treatment at 1700 °C, β-Si3N4 crystallized in a glassy matrix containing magnesium. Resulting samples had an open-pore structure with porosity of 74–84 vol. %, and density of 0.48-0.75 g.cm?3. Combination of high porosity and pore size of <40 μm led to compressive strengths of 1.1–1.6 MPa. 相似文献
5.
Dr. Mimouna Madaoui Dr. Olivier Vidal Albert Meyer Mathieu Noël Prof. Dr. Jean-Marie Lacroix Dr. Jean-Jacques Vasseur Prof. Dr. Alberto Marra Dr. François Morvan 《Chembiochem : a European journal of chemical biology》2020,21(23):3433-3448
Galacto- and fuco-clusters conjugated with one to three catechol or hydroxamate motifs were synthesised to target LecA and LecB lectins of Pseudomonas aeruginosa (PA) localised in the outer membrane and inside the bacterium. The resulting glycocluster–pseudosiderophore conjugates were evaluated as Trojan horses to cross the outer membrane of PA by iron transport. The data suggest that glycoclusters with catechol moieties are able to hijack the iron transport, whereas those with hydroxamates showed strong nonspecific interactions. Mono- and tricatechol galactoclusters ( G1C and G3C ) were evaluated as inhibitors of infection by PA in comparison with the free galactocluster ( G0 ). All of them exhibited an inhibitory effect between 46 to 75 % at 100 μM, with a higher potency than G0 . This result shows that LecA localised in the outer membrane of PA is involved in the infection mechanism. 相似文献
6.
Thomas R. Savage Fernando Almeida-Trasvina Ehecatl A. del-Rio Chanona Robin Smith Dondga Zhang 《American Institute of Chemical Engineers》2021,67(11):e17358
With liquefied natural gas becoming increasingly prevalent as a flexible source of energy, the design and optimization of industrial refrigeration cycles becomes even more important. In this article, we propose an integrated surrogate modeling and optimization framework to model and optimize the complex CryoMan Cascade refrigeration cycle. Dimensionality reduction techniques are used to reduce the large number of process decision variables which are subsequently supplied to an array of Gaussian processes, modeling both the process objective as well as feasibility constraints. Through iterative resampling of the rigorous model, this data-driven surrogate is continually refined and subsequently optimized. This approach was not only able to improve on the results of directly optimizing the process flow sheet but also located the set of optimal operating conditions in only 2 h as opposed to the original 3 weeks, facilitating its use in the operational optimization and enhanced process design of large-scale industrial chemical systems. 相似文献
7.
Lucas Jégo Daniel Milési Jean-Jacques Robin Christine Joly-Duhamel 《Polymer Engineering and Science》2020,60(1):95-103
The photocrosslinking of thick samples of 5-ethylidene-2-norbornene–ethylene propylene diene monomer (ENB-EPDM) under air at room temperature was investigated. First, a model study was carried out on low-molecular weight oligomers: squalene, 1,2-polybutadiene, and 1,4-polybutadiene. Several crosslinking agents (meth(acrylics), bismaleimide, and thiol) combined with various photoinitiators were tested to improve the reactivity of these oligomers under UV irradiation. Gel contents, crosslinking densities, viscosities, and viscoelastic properties were measured in order to characterize the extent of crosslinking. Acrylate-based crosslinking agents appeared to be the most reactive species and these results were then applied to a low-molecular weight EPDM. Several photoinitiators were tested and benzophenone turned out to be the most efficient photoinitiator when combined with trimethylolpropane triacrylate. Finally, a commercial EPDM was subsequently photocrosslinked and high gel content and crosslinking density were obtained after only 2 min of irradiation. POLYM. ENG. SCI., 60:95–103, 2020. © 2019 Society of Plastics Engineers 相似文献
8.
9.
Junyi Che Adrian Najer Anna K. Blakney Paul F. McKay Mohamed Bellahcene Charles W. Winter Amalia Sintou Jiaqing Tang Timothy J. Keane Michael D. Schneider Robin J. Shattock Susanne Sattler Molly M. Stevens 《Advanced materials (Deerfield Beach, Fla.)》2020,32(48):2003598
Uncontrolled inflammation is a major pathological factor underlying a range of diseases including autoimmune conditions, cardiovascular disease, and cancer. Improving localized delivery of immunosuppressive drugs to inflamed tissue in a non-invasive manner offers significant promise to reduce severe side effects caused by systemic administration. Here, a neutrophil-mediated delivery system able to transport drug-loaded nanocarriers to inflamed tissue by exploiting the inherent ability of neutrophils to migrate to inflammatory tissue is reported. This hybrid system (neutrophils loaded with liposomes ex vivo) efficiently migrates in vitro following an inflammatory chemokine gradient. Furthermore, the triggered release of loaded liposomes and reuptake by target macrophages is studied. The migratory behavior of liposome-loaded neutrophils is confirmed in vivo by demonstrating the delivery of drug-loaded liposomes to an inflamed skeletal muscle in mice. A single low-dose injection of the hybrid system locally reduces inflammatory cytokine levels. Biodistribution of liposome-loaded neutrophils in a human-disease-relevant myocardial ischemia reperfusion injury mouse model after i.v. injection confirms the ability of injected neutrophils to carry loaded liposomes to inflammation sites. This strategy shows the potential of nanocarrier-loaded neutrophils as a universal platform to deliver anti-inflammatory drugs to promote tissue regeneration in inflammatory diseases. 相似文献
10.
Daniel Whittaker Andreas Geist Giuseppe Modolo Robin Taylor Mark Sarsfield Andreas Wilden 《溶剂提取与离子交换》2018,36(3):223-256
Over the last decade there has been much interest in the applications of diglycolamide (DGA) ligands for the extraction of the trivalent lanthanide and actinide ions from PUREX high active raffinates or dissolved spent nuclear fuel. Of the DGAs, the N,N,N’,N’-tetraoctyldiglycolamide (TODGA) is the best known and most widely studied. A number of new actinide separation processes have been proposed based on extraction with TODGA. This review covers TODGA-based processes and extraction data, specifically focusing on how phase modifiers have been used to increase metal loading and thus enhance the operating process envelopes. Effects of third phase formation and the organic phase speciation are reviewed in this context. Relevant aspects of the extraction chemistry of important solvents (TODGA-modifier-diluent combinations) are described and their performances demonstrated by a consideration of the published flowsheet tests. It is seen that modifiers are successfully enabling the use of TODGA in actinide separation processes but to date the identification and testing of suitable modifiers has been rather empirical. There is a growing understanding of the fundamental chemistry occurring in the organic phase and how that affects extractant speciation and metal loading capacity but studies are still needed if TODGA-based flowsheets are to become an industrially deployable option for minor actinide (MA) recovery processes. 相似文献