首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   59篇
  免费   7篇
电工技术   1篇
化学工业   13篇
机械仪表   2篇
建筑科学   4篇
能源动力   4篇
轻工业   2篇
无线电   6篇
一般工业技术   20篇
冶金工业   3篇
原子能技术   1篇
自动化技术   10篇
  2024年   1篇
  2023年   2篇
  2021年   6篇
  2020年   2篇
  2019年   2篇
  2018年   3篇
  2017年   1篇
  2016年   7篇
  2015年   2篇
  2014年   6篇
  2013年   5篇
  2012年   7篇
  2011年   7篇
  2010年   1篇
  2009年   5篇
  2008年   3篇
  2007年   1篇
  2006年   3篇
  2001年   1篇
  1999年   1篇
排序方式: 共有66条查询结果,搜索用时 188 毫秒
1.
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   
2.
Despite companies face several challenges when redesigning their supply chain for the Circular Economy, the literature lacks a systematisation of such challenges and of the ways to overcome them. Through a systematic literature review, this paper identifies and systematises 24 challenges that may hamper a supply chain redesign for the Circular Economy. Sixteen among these challenges are well known from research in related topics. On the contrary, the remaining eight are relatively new or take a different relevance within the Circular Economy context. A multiple case study in the household appliance supply chain is carried out, to explore how these challenges appear in practice and how companies may tackle them. The cases analysed involve actors at different supply chain levels, and findings suggest that a great degree of vertical integration by one actor in the supply chain is not a necessary condition for Circular Economy implementation. The empirical study, in conjunction with the literature analysis, leads to the development of a framework linking the challenges to specific levers that companies may pursue to overcome them. The framework can be seen as a reference for managers undertaking the path towards Circular Economy.  相似文献   
3.
4.
The occurrence of Pseudomonas aeruginosa (PA) persisters, including viable but non-culturable (VBNC) forms, subpopulations of tolerant cells that can survive high antibiotic doses, is the main reason for PA lung infections failed eradication and recurrence in Cystic Fibrosis (CF) patients, subjected to life-long, cyclic antibiotic treatments. In this paper, we investigated the role of subinhibitory concentrations of different anti-pseudomonas antibiotics in the maintenance of persistent (including VBNC) PA cells in in vitro biofilms. Persisters were firstly selected by exposure to high doses of antibiotics and their abundance over time evaluated, using a combination of cultural, qPCR and flow cytometry assays. Two engineered GFP-producing PA strains were used. The obtained results demonstrated a major involvement of tobramycin and bacterial cell wall-targeting antibiotics in the resilience to starvation of VBNC forms, while the presence of ciprofloxacin and ceftazidime/avibactam lead to their complete loss. Moreover, a positive correlation between tobramycin exposure, biofilm production and c-di-GMP levels was observed. The presented data could allow a deeper understanding of bacterial population dynamics during the treatment of recurrent PA infections and provide a reliable evaluation of the real efficacy of the antibiotic treatments against the bacterial population within the CF lung.  相似文献   
5.
Accident data have shown that in pedestrian accidents with high-fronted vehicles (SUVs and vans) the risk of pedestrian head injuries from the contact with the ground is higher than with low-fronted vehicles (passenger cars). However, the reasons for this remain poorly understood. This paper addresses this question using multibody modelling to investigate the influence of vehicle front height and shape in pedestrian accidents on the mechanism of impact with the ground and on head ground impact speed. To this end, a set of 648 pedestrian/vehicle crash simulations was carried out using the MADYMO multibody simulation software. Impacts were simulated with six vehicle types at three impact speeds (20, 30, 40 km/h) and three pedestrian types (50th % male, 5th % female, and 6-year-old child) at six different initial stance configurations, stationary and walking at 1.4 m/s.  相似文献   
6.
Epidemiologic studies indicate that millions of people suffer from recurrent cystitis, a pathology requiring antibiotic prophylaxis and entailing high social costs. Cranberry is a traditional folk remedy for cystitis and, which, in the form of a variety of products and formulations has over several decades undergone extensive evaluation for the management of urinary tract infections (UTI). The aim of this retrospective study is to summarize and review the most relevant and recent preclinical and clinical studies on cranberries for the treatment of UTIs. The scientific literature selected for this review was identified by searches of Medline via PubMed. A variety of recent experimental evidence has shed light on the mechanism underlying the anti-adhesive properties of proanthrocyanidins, their structure–activity relationships, and pharmacokinetics. Analysis of clinical studies and evaluation of the cranberry efficacy/safety ratio in the prevention of UTIs strongly support the use of cranberry in the prophylaxis of recurrent UTIs in young and middle-aged women. However, evidence of its clinical use among other patients remains controversial.  相似文献   
7.
Polymer-based solar cells (PSC) represent a promising technology in the field of photovoltaics, although they still suffer from poor environmental stability. Poly(3-hexylthiophene) (P3HT) is one of the most commonly employed electron-donor materials for the preparation of the photo-active layer of PSC and it is known to undergo degradation when exposed to light. In this work, the degradation of P3HT was studied by irradiating polymer films by means of simulated sunlight. The results of this study highlighted a remarkable instability of P3HT. Substantial modifications of the infrared as well as of the UV–Vis spectra of the polymer were reported and a degradation pathway was suggested, in agreement with recent literature results. In order to stabilize the structure, two additives were evaluated namely a standard Hindered Amine Light Stabilizer (HALS) and Multi-Walled Carbon Nanotubes (MWCNT). The addition of MWCNT appeared to significantly reduce the rate of degradation.  相似文献   
8.
Hysteretic rate-independent constitutive laws are introduced within the framework of continuum thermodynamics with internal variables and revisited using concepts and arguments related to dynamical system theory. The evolution of internal variables is formulated either by a system of differential equations or by the associated phase flow. The restrictions implied by rate independence and thermodynamics are pointed out. Within this framework, the class of models with Masing hysteretic rules and Bouc endochronic relations are reviewed, and notions such as irreversibility, noninvertibility, and memory effects are discussed having recourse to different choices of internal variables. By introducing plastic strain as the internal variable, thermodynamic admissibility is proved for both models. However, while the processes with Masing rules exhibit a limited memory and are therefore noninvertible, the processes based on Bouc models are shown to have full memory and to be invertible though irreversible.  相似文献   
9.
Klebsiella pneumoniae (Kp) is an opportunistic pathogen and the leading cause of healthcare-associated infections, mostly affecting subjects with compromised immune systems or suffering from concurrent bacterial infections. However, the dramatic increase in hypervirulent strains and the emergence of new multidrug-resistant clones resulted in Kp occurrence among previously healthy people and in increased morbidity and mortality, including neonatal sepsis and death across low- and middle-income countries. As a consequence, carbapenem-resistant and extended spectrum β-lactamase-producing Kp have been prioritized as a critical anti-microbial resistance threat by the World Health Organization and this has renewed the interest of the scientific community in developing a vaccine as well as treatments alternative to the now ineffective antibiotics. Capsule polysaccharide is the most important virulence factor of Kp and plays major roles in the pathogenesis but its high variability (more than 100 different types have been reported) makes the identification of a universal treatment or prevention strategy very challenging. However, less variable virulence factors such as the O-Antigen, outer membrane proteins as fimbriae and siderophores might also be key players in the fight against Kp infections. Here, we review elements of the current status of the epidemiology and the molecular pathogenesis of Kp and explore specific bacterial antigens as potential targets for both prophylactic and therapeutic solutions.  相似文献   
10.
A new photoelectrochromic device (PECD) is presented in this work proposing the combination of a WO3‐based electrochromic device (ECD) and a polymer‐based dye‐sensitized solar cell (DSSC). In the newly designed architecture, a photocurable polymeric membrane is employed as quasi‐solid electrolyte for both the ECD and the DSSC. In addition, a photocurable fluoropolymeric system is incorporated as solution‐processable external protective thin coating film with easy‐cleaning and UV‐shielding functionalities. Such new polymer‐based device assembly is characterized by excellent device operation with improved photocoloration efficiency and switching ability compared with analogous PECDs based on standard liquid electrolyte systems. In addition, long‐term (>2100 h) stability tests under continuous exposure to real outdoor conditions reveal the remarkable performance stability of this new quasi‐solid PECD system, attributed to the protective action of the photocurable fluorinated coating that effectively prevents photochemical and physical degradation of the PECD components during operation. This first example of quasi‐solid PECD systems paves the way for a new generation of thermally, electrochemically, and photochemically stable polymer‐based PECDs, and provides for the first time a clear demonstration of their true potential as readily upscalable smart window components for energy‐saving buildings.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号