全文获取类型
收费全文 | 578篇 |
免费 | 38篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 315篇 |
金属工艺 | 3篇 |
机械仪表 | 11篇 |
建筑科学 | 22篇 |
矿业工程 | 1篇 |
能源动力 | 14篇 |
轻工业 | 84篇 |
水利工程 | 6篇 |
无线电 | 17篇 |
一般工业技术 | 86篇 |
冶金工业 | 7篇 |
原子能技术 | 2篇 |
自动化技术 | 45篇 |
出版年
2024年 | 1篇 |
2023年 | 25篇 |
2022年 | 119篇 |
2021年 | 107篇 |
2020年 | 32篇 |
2019年 | 25篇 |
2018年 | 32篇 |
2017年 | 22篇 |
2016年 | 24篇 |
2015年 | 21篇 |
2014年 | 23篇 |
2013年 | 33篇 |
2012年 | 20篇 |
2011年 | 31篇 |
2010年 | 17篇 |
2009年 | 19篇 |
2008年 | 15篇 |
2007年 | 8篇 |
2006年 | 11篇 |
2005年 | 6篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1984年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有616条查询结果,搜索用时 15 毫秒
551.
552.
Giuliano Freddi Hiroshi Kato Masuhiro Tsukada Giulia Allara Hideki Shiozaki 《应用聚合物科学杂志》1995,55(3):481-487
Domestic (Bombyx mori) and wild (tussah, Antheraea pernyi) silk fabrics were treated with diluted NaOH solutions by the pad/batch method. The equillbrium moisture regain of tussah silk fibers increased steadily with alkaline treatment, while that of B. mori did not change. B. mori tensile strenght and elongation at break were slightly impaired. The average molecular orientation and crystallinity of both kinds of silk remained unchanged. Differential scanning calorimetry (DSC) and thermomechanical analysis(TMA) showed that the thermal behavior of B. mori silk was almost unaffected, while that of tussah exhibited slight changes in the temperature range 250–300°C. By dynamic mechanical measurements (DMA) it was elucidated that both storage and loss moduli of B. mori silk fibers decreased following NaOH treatment. On the other hand, tussah silk exhibited a noticeable upward shift of the major loss peak. Alkali-treated tussah silk fibers, dyed with an acid dyestuff, attained a lower degree of dye-bath exhaustion. © 1995 John Wiley & Sons, Inc. 相似文献
553.
Giulia Sita Patrizia Hrelia Andrea Tarozzi Fabiana Morroni 《International journal of molecular sciences》2016,17(9)
Parkinson’s disease (PD) is recognized as the second most common neurodegenerative disorder and is characterized by a slow and progressive degeneration of dopaminergic neurons in the substantia nigra. Despite intensive research, the mechanisms involved in neuronal loss are not completely understood yet; however, misfolded proteins, oxidative stress, excitotoxicity and inflammation play a pivotal role in the progression of the pathology. Neuroinflammation may have a greater function in PD pathogenesis than initially believed, taking part in the cascade of events that leads to neuronal death. To date, no efficient therapy, able to arrest or slow down PD, is available. In this context, the need to find novel strategies to counteract neurodegenerative progression by influencing diseases’ pathogenesis is becoming increasingly clear. Isothiocyanates (ITCs) have already shown interesting properties in detoxification, inflammation, apoptosis and cell cycle regulation through the induction of phase I and phase II enzyme systems. Moreover, ITCs may be able to modulate several key points in oxidative and inflammatory evolution. In view of these considerations, the aim of the present review is to describe ITCs as pleiotropic compounds capable of preventing and modulating the evolution of PD. 相似文献
554.
Luca Rotundo Pina M. Fratamico Giulia Amagliani Elisa Carloni Enrica Omiccioli Mauro Magnani 《Food Analytical Methods》2018,11(10):2822-2834
The aim of this study was to assess the performance of the Diatheva STEC FLUO and BAX System real-time PCR assays for detection of Shiga toxin-producing Escherichia coli (STEC) (stx1/stx2 and eae target genes) and O-group identification in ground beef and bean sprout samples. Ground beef (325 g or 25 g) and mung bean sprout (25 g) samples were inoculated with ~?10 CFU of the “top five” STEC (O157:H7, O26, O103, O111, and O145 as specified in EU regulation ISO13136:2012), enriched using different broths and incubation temperatures, and tested using the Diatheva and BAX real-time PCR assays. In ground beef, both molecular methods were able to detect the “top five” STEC, and lower Ct values were observed for the Diatheva kits compared to BAX System. The O111-contaminated samples gave negative results with both methods using mTSB?+?novobiocin for enrichment. In bean sprouts, both methods provided positive results, although detection was not possible using mTSB?+?acriflavin/cefsulodin/vancomycin for enrichment. In conclusion, the Diatheva and BAX methods detected the “top five” STEC in ground beef and bean sprouts when inoculated at low levels. Both assays provided equivalent results in terms of performance and reliability. Thus, the Diatheva kits are comparable to reference STEC-detection methods and could be used by the food industry to reliably detect the “top five” STEC. 相似文献
555.
Barbara Carletti Emanuela Piermarini Giulia Tozzi Lorena Travaglini Alessandra Torraco Anna Pastore Marco Sparaco Sara Petrillo Rosalba Carrozzo Enrico Bertini Fiorella Piemonte 《International journal of molecular sciences》2014,15(4):5789-5806
Friedreich’s ataxia (FRDA) is a hereditary neurodegenerative disease characterized by a reduced synthesis of the mitochondrial iron chaperon protein frataxin as a result of a large GAA triplet-repeat expansion within the first intron of the frataxin gene. Despite neurodegeneration being the prominent feature of this pathology involving both the central and the peripheral nervous system, information on the impact of frataxin deficiency in neurons is scant. Here, we describe a neuronal model displaying some major biochemical and morphological features of FRDA. By silencing the mouse NSC34 motor neurons for the frataxin gene with shRNA lentiviral vectors, we generated two cell lines with 40% and 70% residual amounts of frataxin, respectively. Frataxin-deficient cells showed a specific inhibition of mitochondrial Complex I (CI) activity already at 70% residual frataxin levels, whereas the glutathione imbalance progressively increased after silencing. These biochemical defects were associated with the inhibition of cell proliferation and morphological changes at the axonal compartment, both depending on the frataxin amount. Interestingly, at 70% residual frataxin levels, the in vivo treatment with the reduced glutathione revealed a partial rescue of cell proliferation. Thus, NSC34 frataxin silenced cells could be a suitable model to study the effect of frataxin deficiency in neurons and highlight glutathione as a potential beneficial therapeutic target for FRDA. 相似文献
556.
Milou Groot Nibbelink Giulia Marchioli Lorenzo Moroni Marcel Karperien Aart Van Apeldoorn 《International journal of molecular sciences》2016,17(9)
In vitro research in the field of type I diabetes is frequently limited by the availability of a functional model for islets of Langerhans. This method shows that by the addition of theophylline to the glucose buffers, mouse insulinoma MIN6 and rat insulinoma INS1E pseudo-islets can serve as a model for islets of Langerhans for in vitro research. The effect of theophylline is dose- and cell line-dependent, resulting in a minimal stimulation index of five followed by a rapid return to baseline insulin secretion by reducing glucose concentrations after a first high glucose stimulation. This protocol solves issues concerning in vitro research for type I diabetes as donors and the availability of primary islets of Langerhans are limited. To avoid the limitations of using human donor material, cell lines represent a valid alternative. Many different β cell lines have been reported, but the lack of reproducible responsiveness to glucose stimulation remains a challenge. 相似文献
557.
Fredi Giulia Dorigato Andrea Pegoretti Alessandro 《Mechanics of Time-Dependent Materials》2020,24(3):395-418
Mechanics of Time-Dependent Materials - Dynamic-mechanical analysis (DMA) was performed to investigate the viscoelastic response of multifunctional laminates for thermal energy storage (TES). The... 相似文献
558.
559.
Adaptive web-based educational systems provide learners with personalized courses, where learning material is delivered to learners taking into account their personal learning needs, learning styles and learning progresses. In this paper we show the Lecomps5 system, a didactic framework, supporting the automated production and adaptation of personalized courses, implemented in the Lecomps5 system. In particular, this framework was designed in order to address the teacher’s satisfaction issue, arising in many systems that are quite demanding in terms of the teacher’s work and range of activities. Lecomps5 allows the teacher, through a simple and intuitive didactic tool, to define learning material, specify its characteristics pertaining to personalization and define, to some extent, the didactic strategies to be applied. In order to support both the management of learning material and the automated construction of personalized courses, the system embeds a planner, based on Linear Temporal Logic. The selection of learning material, its sequencing, and the delivery of courses, is performed according to both learners’ initial and run-time knowledge and learning styles. The teacher can focus more on her didactic tasks and preferences rather than on the available authoring tools, and spend less time to generate courses. Finally we show encouraging results from experimentation we conducted to test the system from a teacher’s point of view. 相似文献
560.
Gualtiero Gusmano Giampiero Montesperelli Enrico Traversa Giulia Mattogno 《Journal of the American Ceramic Society》1993,76(3):743-750
Active elements for humidity sensors based upon MgAl2 O4 thin films or sintered pellets were investigated. Thin films were deposited on Si/SiO2 substrates by radiofrequency (rf) sputtering. Sintered MgAl2 O4 pellets were prepared by traditional ceramic processing. Scanning electron microscopy (SEM) analysis showed that the thin films were rather dense and homogeneous, made up of clustered particles of about 20–30 nm, while the pellets showed a wide pore-size distribution. X-ray photoelectron spectroscopy (XPS) demonstrated that the thin films have a stoichiometry close to that of MgAl2 O4 . Sintered MgAl2 O4 is crystalline, while it is disordered in thin-film form. The presence of two different components of the Al 2 p peaks was correlated with the structural difference between pellets and thin films. The relationship between good film–substrate adhesive properties and the chemical composition at the interface was studied. The electrical properties of the sensing elements were studied at 40°C in environments at different relative humidity (RH) values between 2% and 95%, using ac impedance spectroscopy. MgAl2 O4 thin films showed interesting characteristics in terms of their use in humidity-measurement devices. Resistance versus RH sensitivity values showed variations as high as 4 orders of magnitude in the RH range tested for thin films, and 5 orders of magnitude for pellets. The differences in the electrical behavior of MgAl2 O4 pellets and thin films were correlated with their different microstructures. 相似文献