全文获取类型
收费全文 | 1400篇 |
免费 | 73篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 39篇 |
化学工业 | 255篇 |
金属工艺 | 15篇 |
机械仪表 | 32篇 |
建筑科学 | 40篇 |
能源动力 | 37篇 |
轻工业 | 113篇 |
水利工程 | 13篇 |
无线电 | 187篇 |
一般工业技术 | 238篇 |
冶金工业 | 212篇 |
原子能技术 | 12篇 |
自动化技术 | 281篇 |
出版年
2023年 | 8篇 |
2022年 | 10篇 |
2021年 | 60篇 |
2020年 | 45篇 |
2019年 | 45篇 |
2018年 | 46篇 |
2017年 | 28篇 |
2016年 | 40篇 |
2015年 | 37篇 |
2014年 | 62篇 |
2013年 | 94篇 |
2012年 | 95篇 |
2011年 | 84篇 |
2010年 | 61篇 |
2009年 | 75篇 |
2008年 | 81篇 |
2007年 | 56篇 |
2006年 | 52篇 |
2005年 | 42篇 |
2004年 | 46篇 |
2003年 | 43篇 |
2002年 | 23篇 |
2001年 | 17篇 |
2000年 | 12篇 |
1999年 | 29篇 |
1998年 | 69篇 |
1997年 | 35篇 |
1996年 | 39篇 |
1995年 | 18篇 |
1994年 | 18篇 |
1993年 | 11篇 |
1992年 | 13篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 8篇 |
1988年 | 6篇 |
1987年 | 8篇 |
1986年 | 2篇 |
1985年 | 10篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 5篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1976年 | 8篇 |
1974年 | 3篇 |
1973年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有1474条查询结果,搜索用时 31 毫秒
1.
Carlo Dal Lin Claudia Maria Radu Giuseppe Vitiello Paola Romano Albino Polcari Sabino Iliceto Paolo Simioni Francesco Tona 《International journal of molecular sciences》2021,22(1)
Mechanical vibrations seem to affect the behaviour of different cell types and the functions of different organs. Pressure waves, including acoustic waves (sounds), could affect cytoskeletal molecules via coherent changes in their spatial organization and mechano-transduction signalling. We analyzed the sounds spectra and their fractal features. Cardiac muscle HL1 cells were exposed to different sounds, were stained for cytoskeletal markers (phalloidin, beta-actin, alpha-tubulin, alpha-actinin-1), and studied with multifractal analysis (using FracLac for ImageJ). A single cell was live-imaged and its dynamic contractility changes in response to each different sound were analysed (using Musclemotion for ImageJ). Different sound stimuli seem to influence the contractility and the spatial organization of HL1 cells, resulting in a different localization and fluorescence emission of cytoskeletal proteins. Since the cellular behaviour seems to correlate with the fractal structure of the sound used, we speculate that it can influence the cells by virtue of the different sound waves’ geometric properties that we have photographed and filmed. A theoretical physical model is proposed to explain our results, based on the coherent molecular dynamics. We stress the role of the systemic view in the understanding of the biological activity. 相似文献
2.
Macrophages are highly heterogeneous and plastic immune cells with peculiar characteristics dependent on their origin and microenvironment. Following pathogen infection or damage, circulating monocytes can be recruited in different tissues where they differentiate into macrophages. Stimuli present in the surrounding milieu induce the polarisation of macrophages towards a pro-inflammatory or anti-inflammatory profile, mediating inflammatory or homeostatic responses, respectively. However, macrophages can also derive from embryonic hematopoietic precursors and reside in specific tissues, actively participating in the development and the homeostasis in physiological conditions. Pancreatic islet resident macrophages are present from the prenatal stages onwards and show specific surface markers and functions. They localise in close proximity to β-cells, being exquisite sensors of their secretory ability and viability. Over the years, the crucial role of macrophages in β-cell differentiation and homeostasis has been highlighted. In addition, macrophages are emerging as central players in the initiation of autoimmune insulitis in type 1 diabetes and in the low-grade chronic inflammation characteristic of obesity and type 2 diabetes pathogenesis. The present work reviews the current knowledge in the field, with a particular focus on the mechanisms of communication between β-cells and macrophages that have been described so far. 相似文献
3.
Raffaella Balestrini Cecilia Brunetti Maria Cammareri Sofia Caretto Valeria Cavallaro Eleonora Cominelli Monica De Palma Teresa Docimo Giovanna Giovinazzo Silvana Grandillo Franca Locatelli Erica Lumini Dario Paolo Cristina Patan Francesca Sparvoli Marina Tucci Elisa Zampieri 《International journal of molecular sciences》2021,22(6)
Plant specialized metabolites (SMs) play an important role in the interaction with the environment and are part of the plant defense response. These natural products are volatile, semi-volatile and non-volatile compounds produced from common building blocks deriving from primary metabolic pathways and rapidly evolved to allow a better adaptation of plants to environmental cues. Specialized metabolites include terpenes, flavonoids, alkaloids, glucosinolates, tannins, resins, etc. that can be used as phytochemicals, food additives, flavoring agents and pharmaceutical compounds. This review will be focused on Mediterranean crop plants as a source of SMs, with a special attention on the strategies that can be used to modulate their production, including abiotic stresses, interaction with beneficial soil microorganisms and novel genetic approaches. 相似文献
4.
Benedetta Angeloni Rachele Bigi Gianmarco Bellucci Rosella Mechelli Chiara Ballerini Carmela Romano Emanuele Morena Giulia Pellicciari Roberta Reni Virginia Rinaldi Maria Chiara Buscarinu Silvia Romano Giovanni Ristori Marco Salvetti 《International journal of molecular sciences》2021,22(7)
Multiple sclerosis is a complex, multifactorial, dysimmune disease prevalent in women. Its etiopathogenesis is extremely intricate, since each risk factor behaves as a variable that is interconnected with others. In order to understand these interactions, sex must be considered as a determining element, either in a protective or pathological sense, and not as one of many variables. In particular, sex seems to highly influence immune response at chromosomal, epigenetic, and hormonal levels. Environmental and genetic risk factors cannot be considered without sex, since sex-based immunological differences deeply affect disease onset, course, and prognosis. Understanding the mechanisms underlying sex-based differences is necessary in order to develop a more effective and personalized therapeutic approach. 相似文献
5.
Massimo Dal Monte Maurizio Cammalleri Rosario Amato Salvatore Pezzino Roberta Corsaro Paola Bagnoli Dario Rusciano 《International journal of molecular sciences》2020,21(23)
Melatonin is of great importance for regulating several eye processes, including pressure homeostasis. Melatonin in combination with agomelatine has been recently reported to reduce intraocular pressure (IOP) with higher efficacy than each compound alone. Here, we used the methylcellulose (MCE) rat model of hypertensive glaucoma, an optic neuropathy characterized by the apoptotic death of retinal ganglion cells (RGCs), to evaluate the hypotensive and neuroprotective efficacy of an eye drop nanomicellar formulation containing melatonin/agomelatine. Eye tissue distribution of melatonin/agomelatine in healthy rats was evaluated by HPLC/MS/MS. In the MCE model, we assessed by tonometry the hypotensive efficacy of melatonin/agomelatine. Neuroprotection was revealed by electroretinography; by levels of inflammatory and apoptotic markers; and by RGC density. The effects of melatonin/agomelatine were compared with those of timolol (a beta blocker with prevalent hypotensive activity) or brimonidine (an alpha 2 adrenergic agonist with potential neuroprotective efficacy), two drugs commonly used to treat glaucoma. Both melatonin and agomelatine penetrate the posterior segment of the eye. In the MCE model, IOP elevation was drastically reduced by melatonin/agomelatine with higher efficacy than that of timolol or brimonidine. Concomitantly, gliosis-related inflammation and the Bax-associated apoptosis were partially prevented, thus leading to RGC survival and recovered retinal dysfunction. We suggest that topical melatoninergic compounds might be beneficial for ocular health. 相似文献
6.
Roberto C. Dante Pablo Martín-Ramos Pedro Chamorro-Posada Dario Rutto José Vázquez-Cabo Denisse G. Dante 《Fullerenes, Nanotubes and Carbon Nanostructures》2020,28(7):533-540
AbstractIn this work, a new g-C3N4-based Z-scheme with γ-Fe2O3 and β-Ag2Se both n-type semiconductors, and graphite to favor electron exchange is presented. The composite material was studied by XRD, FTIR, UV-Vis, TEM, XPS, TGA, DSC and TOF-SIMS, and the ability of this photocatalytic system to act as a photo-reductant was assessed using crystal violet (CV+) dye. Solar light driven photo-reduction of CV+ in the presence of tri-sodium citrate evidenced a synergistic enhancement of the activity of the composite toward reduction, with ~20 times higher conversion rates per unit of surface area than those of g-C3N4. Photo-oxidation experiments under Xe lamp irradiation in the presence of H2O2 also showed that the AgFeCN composite featured a higher activity (~8×) than g-C3N4. This Z-scheme may deserve further study as a photo-reductant to obtain hydrogen or hydrogenated compounds. Moreover, the use of CV+ may represent a facile procedure that can aid in the selection of new photocatalysts to be used in hydrogen production. 相似文献
7.
Andrea Ballo Alfio Dario Grasso Gaetano Palumbo 《International Journal of Circuit Theory and Applications》2020,48(2):157-161
This paper introduces a simple design strategy to increase the power efficiency of linear charge pumps. The technique exploits a voltage amplitude of the clock signal lower than the supply voltage to reduce the power conversion losses. The nominal output voltage is maintained unaltered by increasing the number of stages. 相似文献
8.
Alessandro Sannino Dr. Elena Gabriele Martina Bigatti Dr. Sara Mulatto Dr. Jacopo Piazzi Dr. Jörg Scheuermann Prof. Dr. Dario Neri Dr. Etienne J. Donckele Dr. Florent Samain 《Chembiochem : a European journal of chemical biology》2019,20(7):955-962
DNA-encoded chemical libraries are often used for the discovery of ligands against protein targets of interest. These large collections of DNA-barcoded chemical compounds are typically screened by using affinity capture methodologies followed by PCR amplification and DNA sequencing procedures. However, the performance of individual steps in the selection procedures has been scarcely investigated, so far. Herein, the quantitative analysis of selection experiments, by using three ligands with different affinity to carbonic anhydrase IX as model compounds, is described. In the first set of experiments, quantitative PCR (qPCR) procedures are used to evaluate the recovery and selectivity for affinity capture procedures performed on different solid-phase supports, which are commonly used for library screening. In the second step, both qPCR and analysis of DNA sequencing results are used to assess the recovery and selectivity of individual carbonic anhydrase IX ligands in a library, containing 360 000 compounds. Collectively, this study reveals that selection procedures can be efficient for ligands with sub-micromolar dissociation constants to the target protein of interest, but also that selection performance dramatically drops if 104 copies per library member are used as the input. 相似文献
9.
Liesel Claeys Chiara Romano Karl De Ruyck Hayley Wilson Beatrice Fervers Michael Korenjak Jiri Zavadil Marc J. Gunter Sarah De Saeger Marthe De Boevre Inge Huybrechts 《Comprehensive Reviews in Food Science and Food Safety》2020,19(4):1449-1464
In recent years, there has been an increasing interest in investigating the carcinogenicity of mycotoxins in humans. This systematic review aims to provide an overview of data linking exposure to different mycotoxins with human cancer risk. Publications (2019 and earlier) of case–control or longitudinal cohort studies were identified in PubMed and EMBASE. These articles were then screened by independent reviewers and their quality was assessed according to the Newcastle–Ottawa scale. Animal, cross‐sectional, and molecular studies satisfied criteria for exclusion. In total, 14 articles were included: 13 case–control studies and 1 longitudinal cohort study. Included articles focused on associations of mycotoxin exposure with primary liver, breast, and cervical cancer. Overall, a positive association between the consumption of aflatoxin‐contaminated foods and primary liver cancer risk was verified. Two case–control studies in Africa investigated the relationship between zearalenone and its metabolites and breast cancer risk, though conflicting results were reported. Two case–control studies investigated the association between hepatocellular carcinoma and fumonisin B1 exposure, but no significant associations were observed. This systematic review incorporates several clear observations of dose‐dependent associations between aflatoxins and liver cancer risk, in keeping with IARC Monograph conclusions. Only few human epidemiological studies investigated the associations between mycotoxin exposures and cancer risk. To close this gap, more in‐depth research is needed to unravel evidence for other common mycotoxins, such as deoxynivalenol and ochratoxin A. The link between mycotoxin exposures and cancer risk has mainly been established in experimental studies, and needs to be confirmed in human epidemiological studies to support the evidence‐based public health strategies. 相似文献