全文获取类型
收费全文 | 265篇 |
免费 | 23篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 5篇 |
化学工业 | 106篇 |
金属工艺 | 3篇 |
机械仪表 | 3篇 |
建筑科学 | 4篇 |
能源动力 | 7篇 |
轻工业 | 23篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
无线电 | 35篇 |
一般工业技术 | 36篇 |
冶金工业 | 22篇 |
自动化技术 | 42篇 |
出版年
2023年 | 10篇 |
2022年 | 24篇 |
2021年 | 39篇 |
2020年 | 11篇 |
2019年 | 12篇 |
2018年 | 15篇 |
2017年 | 17篇 |
2016年 | 15篇 |
2015年 | 5篇 |
2014年 | 14篇 |
2013年 | 18篇 |
2012年 | 10篇 |
2011年 | 15篇 |
2010年 | 5篇 |
2009年 | 9篇 |
2008年 | 12篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 5篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 4篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 2篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1990年 | 2篇 |
1988年 | 1篇 |
排序方式: 共有289条查询结果,搜索用时 15 毫秒
51.
Russo Krauss I Sica F Mattia CA Merlino A 《International journal of molecular sciences》2012,13(3):3782-3800
Serum albumin is one of the most widely studied proteins. It is the most abundant protein in plasma with a typical concentration of 5 g/100 mL and the principal transporter of fatty acids in plasma. While the crystal structures of human serum albumin (HSA) free and in complex with fatty acids, hemin, and local anesthetics have been characterized, no crystallographic models are available on bovine serum albumin (BSA), presumably because of the poor diffraction power of existing hexagonal BSA crystals. Here, the crystallization and diffraction data of a new BSA crystal form, obtained by the hanging drop method using MPEG 5K as precipitating agent, are presented. The crystals belong to space group C2, with unit-cell parameters a = 216.45 Å, b = 44.72 Å, c = 140.18 Å, β = 114.5°. Dehydration was found to increase the diffraction limit of BSA crystals from ~8 Å to 3.2 Å, probably by improving the packing of protein molecules in the crystal lattice. These results, together with a survey of more than 60 successful cases of protein crystal dehydration, confirm that it can be a useful procedure to be used in initial screening as a method of improving the diffraction limits of existing crystals. 相似文献
52.
Rahman MA Penco M Peroni I Ramorino G Grande AM Di Landro L 《ACS applied materials & interfaces》2011,3(12):4865-4874
The development of materials with the ability of intrinsic self-repairing after damage in a fashion resembling that of living tissues has important scientific and technological implications, particularly in relation to cost-effective approaches toward damage management of materials. Natural rubbers with epoxy functional groups in the macromolecular chain (ENR) and ethylene-methacrylic acid ionomers having acid groups partially neutralized with metal ions possess self-repairing behavior following high energy impacts. This research investigates the self-repairing behavior of both ENR and ionomers during ballistic puncture test on the basis of their thermal and mechanical properties. Heterogeneous blending of ionomers and ENR have also been used here as a strategy to tune the thermal and mechanical properties of the materials. Interestingly, blends of sodium ion containing ionomer exhibit complete self-repairing behavior, whereas blends of zinc ion containing ionomer show limited mending. The chemical structure studied by FTIR and thermal analysis shows that both ion content of ionomer and functionality of ENR have significant influence on the self-repairing behavior of blends. The mobility of rubbery phases along with its interaction to ionomer phase in the blends significantly changes the mending capability of materials. The healing behavior of the materials has been discussed on the basis of their thermal, mechanical, and rheological tests for each materials. 相似文献
53.
Technical due diligence (TDD) as an evaluation of the performance of constructed facilities has become an important new field of practice for consultants. Before the financial crisis started in autumn 2008, TDD represented the fastest growing activity in some consulting companies. TDD is usually carried out for buyers or sellers involved in real estate transactions. It can also be part of mergers, including real estate and other assets, or part of facilities management outsourcing. This paper is based on a case study and an interview survey of companies involved in TDD consulting in Denmark and Italy during 2009. The research identifies the current practice and compares it with the recommended practice in international guidelines. The current practice is very diverse and could, in many cases, be improved by a more structured approach and stricter adherence to international guidelines. However, the investigation of the current practice also identifies examples of value-adding practices, which can give the companies in question competitive advantages by differentiation and/or give input to improvements of the recommended practice guidelines. 相似文献
54.
Lorenzo Fanni Mattia Giussani Matteo Marzoli Miglena Nikolaeva‐Dimitrova 《Progress in Photovoltaics: Research and Applications》2014,22(8):910-922
According to uncertainty calculations, the values recorded by means of commercial monitoring systems are expected to be less accurate than those recorded by a system optimized for the measurement of electrical parameters—the so‐called dedicated system (DS). This study aims to verify if a larger expected uncertainty for commercial system (CS) actually turns into a larger spread of the measurements around the true value. In the Airport Bolzano Dolomiti plant, CS and DS are installed on the same photovoltaic arrays. The comparison performed considers the detailed uncertainty budget for the two systems using three performance indicators—energy, yield and performance ratio. Results show that the uncertainty level of the CS is much larger; for example, on performance ratio, it is about four times larger with respect to the optimized one (respectively ±16% and ±4%). Three sources mainly contribute to the uncertainty: measurements of irradiance, current and voltage. The measured values of the electrical parameter are compared in order to verify if the results of the budget calculations turn into a real difference. Results show that the CS is accurate in measuring current and voltage, respectively, ~2% and ~5% of difference from the DS, but not for irradiance—here, the difference is higher than 10%. In particular, the irradiance measured by the CS is systematically smaller; therefore, the performance ratio calculated through the CS is always overestimated and often larger than 100%. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
55.
Righi V Di Nunzio M Danesi F Schenetti L Mucci A Boschetti E Biagi P Bonora S Tugnoli V Bordoni A 《Lipids》2011,46(7):627-636
It is well recognized that a high dietary intake of long-chain polyunsaturated fatty acids (LC-PUFA) has profound benefits
on health and prevention of chronic diseases. In particular, in recent years there has been a dramatic surge of interest in
the health effects of n-3 LC-PUFA derived from fish, eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. Notwithstanding,
the metabolic fate and the effects of these fatty acids once inside the cell has seldom been comprehensively investigated.
Using cultured neonatal rat cardiomyocytes as model system we have investigated for the first time, by means of high-resolution
magic-angle spinning nuclear magnetic resonance (HR-MAS NMR) spectroscopy in combination with gas chromatography (GC), the
modification occurring in the cell lipid environment after EPA and DHA supplementation. The most important difference between
control and n-3 LC-PUFA-supplemented cardiomyocytes highlighted by HR-MAS NMR spectroscopy is the increase of signals from
mobile lipids, identified as triacylglycerols (TAG). The observed increase of mobile TAG is a metabolic response to n-3 LC-PUFA
supplementation, which leads to an increased lipid storage. The sequestration of mobile lipids in lipid bodies provides a
deposit of stored energy that can be accessed in a regulated fashion according to metabolic need. Interestingly, while n-3
LC-PUFA supplementation to neonatal rat cardiomyocytes causes a huge variation in the cell lipid environment, it does not
induce detectable modifications in water-soluble metabolites, suggesting negligible interference with normal metabolic processes. 相似文献
56.
DNA barcoding as a new tool for food traceability 总被引:1,自引:0,他引:1
Andrea Galimberti Fabrizio De Mattia Alessia Losa Ilaria Bruni Silvia Federici Maurizio Casiraghi Stefano Martellos Massimo Labra 《Food research international (Ottawa, Ont.)》2013,50(1):55-63
Food safety and quality are nowadays a major concern. Any case of food alteration, especially when reported by the media, has a great impact on public opinion. There is an increasing demand for the improvement of quality controls, hence addressing scientific research towards the development of reliable molecular tools for food analysis. DNA barcoding is a widely used molecular-based system, which can identify biological specimens, and is used for the identification of both raw materials and processed food. In this review the results of several researches are critically analyzed, in order to exploit the effectiveness of DNA barcoding in food traceability, and to delineate some best practices in the application of DNA barcoding throughout the industrial pipeline. The use of DNA barcoding for food safety and in the identification of commercial fraud is also discussed. 相似文献
57.
Anna Aiello Mattia Emanuela Ligotti Maider Garnica Giulia Accardi Anna Calabr Fanny Pojero Hugo Arasanz Ana Bocanegra Ester Blanco Luisa Chocarro Miriam Echaide Leticia Fernandez-Rubio Pablo Ramos Sergio Pieiro-Hermida Grazyna Kochan Nahid Zareian Farzin Farzaneh David Escors Calogero Caruso Giuseppina Candore 《International journal of molecular sciences》2022,23(17)
Vaccination, being able to prevent millions of cases of infectious diseases around the world every year, is the most effective medical intervention ever introduced. However, immunosenescence makes vaccines less effective in providing protection to older people. Although most studies explain that this is mainly due to the immunosenescence of T and B cells, the immunosenescence of innate immunity can also be a significant contributing factor. Alterations in function, number, subset, and distribution of blood neutrophils, monocytes, and natural killer and dendritic cells are detected in aging, thus potentially reducing the efficacy of vaccines in older individuals. In this paper, we focus on the immunosenescence of the innate blood immune cells. We discuss possible strategies to counteract the immunosenescence of innate immunity in order to improve the response to vaccination. In particular, we focus on advances in understanding the role and the development of new adjuvants, such as TLR agonists, considered a promising strategy to increase vaccination efficiency in older individuals. 相似文献
58.
Barbara Peruzzi Enrica Urciuoli Michela Mariani Laura Chioma Luigi Tomao Ilaria Montano Mattia Algeri Rosa Luciano Danilo Fintini Melania Manco 《International journal of molecular sciences》2023,24(1)
Excess body weight has been considered beneficial to bone health because of its anabolic effect on bone formation; however, this results in a poor quality bone structure. In this context, we evaluated the involvement of circulating extracellular vesicles in the impairment of the bone phenotype associated with obesity. Circulating extracellular vesicles were collected from the plasma of participants with normal weight, as well as overweight and obese participants, quantified by flow cytometry analysis and used to treat mesenchymal stromal cells and osteoblasts to assess their effect on cell differentiation and activity. Children with obesity had the highest amount of circulating extracellular vesicles compared to controls. The treatment of mesenchymal stromal cells with extracellular vesicles from obese participants led to an adipogenic differentiation in comparison to vesicles from controls. Mature osteoblasts treated with extracellular vesicles from obese participants showed a reduction in differentiation markers in comparison to controls. Children with obesity who regularly performed physical exercise had a lower circulating extracellular vesicle amount in comparison to those with a sedentary lifestyle. This pilot study demonstrates how the high amount of circulating extracellular vesicles in children with obesity affects the bone phenotype and that physical activity can partially rescue this phenotype. 相似文献
59.
Gian Domenico Sorarù Katia Girardini Masaki Narisawa Mattia Biesuz 《Journal of the American Ceramic Society》2021,104(7):3097-3104
In this study the high temperature stability (crystallization and decomposition) of two silicon oxycarbide glasses with a similar amount of free carbon (8.3 vs 9.6 wt%) but different content of Si-C bonds (SiC0.22O1.57 vs SiC0.07O1.86) is presented. The two SiOC glasses are obtained from the same precursor (2 µm methyl-silsesquioxane spheres) via pyrolysis at 1100°C in inert (Ar) or reactive (CO2) atmospheres. Further annealing in Ar flow at temperatures above 1100°C and up to 1500°C is performed and the samples are characterized by Fourier Transformed Infrared Spectroscopy (FT-IR) and X-ray diffraction (XRD). For comparison purposes the same precursor was annealed in air flow to obtain SiO2 and its high temperature evolution is also studied. Results suggest that the onset for the carbothermal reduction is not dependent on the amount of Si-C bonds. Moreover, contrary to what is usually reported in the scientific literature, silica phase present in the SiOC glasses does not show, in the same experimental conditions, superior crystallization resistance compared to pure silica glass. 相似文献
60.
Mattia Gaboardi Nicola Sarzi Amadè Mauro Riccò Chiara Milanese Alessandro Girella Marta Gioventù Felix Fernandez-Alonso 《International Journal of Hydrogen Energy》2018,43(34):16766-16773
We herein report on the synthesis of mixed alkali cluster intercalated fullerides NaxLiy?xC60 (y = 12; x = 1–6) by a two-steps mechanochemical reaction of fullerene with sodium and lithium. These compounds crystallize in the cubic lattice of C60 displaying a contracted lattice parameter with respect to the Na6C60 parent structure. The analysis of the hydrogen sorption behaviour shows a slight decrease in the dehydrogenation enthalpy for y = 12 with respect to the sodium free member. Raman spectroscopy highlighted a partial electron transfer from alkali metals to C60, suggesting the presence of charged sodium/lithium clusters. Finally, we applied muon spectroscopy to understand the different hydrogenation mechanisms in NaxLi6?xC60 and NaxLi12?xC60 and explain their different performance. 相似文献