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   306篇
  免费   6篇
电工技术   1篇
化学工业   85篇
金属工艺   4篇
机械仪表   6篇
建筑科学   9篇
能源动力   2篇
轻工业   54篇
水利工程   1篇
无线电   22篇
一般工业技术   46篇
冶金工业   39篇
原子能技术   2篇
自动化技术   41篇
  2023年   3篇
  2022年   5篇
  2021年   14篇
  2020年   3篇
  2019年   6篇
  2018年   6篇
  2017年   4篇
  2016年   9篇
  2015年   8篇
  2014年   8篇
  2013年   23篇
  2012年   25篇
  2011年   14篇
  2010年   13篇
  2009年   13篇
  2008年   19篇
  2007年   22篇
  2006年   15篇
  2005年   15篇
  2004年   13篇
  2003年   8篇
  2002年   8篇
  2001年   4篇
  1999年   4篇
  1998年   4篇
  1997年   2篇
  1996年   11篇
  1995年   1篇
  1994年   3篇
  1993年   5篇
  1990年   4篇
  1989年   2篇
  1988年   3篇
  1987年   1篇
  1986年   1篇
  1985年   3篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1978年   1篇
  1974年   2篇
排序方式: 共有312条查询结果,搜索用时 31 毫秒
21.
Pancreatic beta-cells have a crucial role in the regulation of blood glucose homeostasis by the production and secretion of insulin. In type 1 diabetes (T1D), an autoimmune reaction against the beta-cells together with the presence of inflammatory cytokines and ROS in the islets leads to beta-cell dysfunction and death. This review gives an overview of proteomic studies that lead to better understanding of beta-cell functioning in T1D. Protein profiling of isolated islets and beta-cell lines in health and T1D contributed to the unraveling of pathways involved in cytokine-induced cell death. In addition, by studying the serological proteome of T1D patients, new biomarkers and beta-cell autoantigens were discovered, which may improve screening tests and follow-up of T1D development. Interestingly, an important role for PTMs was demonstrated in the generation of beta-cell autoantigens. To conclude, proteomic techniques are of indispensable value to improve the knowledge on beta-cell function in T1D and the search toward therapeutic targets.  相似文献   
22.
Gold nanomaterials are promising objects for applications in optics and medicine because of their unique properties related to the Surface Plasmon Resonances (SPR) phenomena. It is possible to tune these properties with the control of the size and shape of the nanomaterials. Gold hollow spheres nanomaterials are an interesting concept for encapsulation of either dyes or drugs. The study of their properties and their behavior in a bio-environment still remains scarce and some phenomena are still to be explained in particular regarding local field enhancement effect or quenching of their photophysical properties. In this work we describe a process allowing inclusion of optical dyes in gold nanoshells and evaluate the optical properties.  相似文献   
23.
In this paper the effect of operating parameters on biotrickling filter performance degrading chlorobenzene and o-dichlorobenzene mixture were studied. The large laboratory scale biofilter, total volume 40 L, filled with inert packing material was used. The biomass adaptation and cultivation were performed in a batch fermentor and were used to inoculate the biotrickling filter. After a starting period, the influence of the substrate load increase, liquid recirculation flow rate, and empty bed retention time on elimination capacity and removal efficiency were found. The most important recirculation liquid parameters were analyzed every day, that is: concentration of metabolites, dissolved organic carbon, nitrate, chloride, and biomass. A good correlation was found between intermediate concentration and the removal efficiency of the biotrickling filter. The measurements of the absorbance, very easy and rapid, can be used as a control parameter of the biofiltration efficiency.  相似文献   
24.
This study addresses the question of whether peripheral vision is involved in the control of hand trajectory direction during an aiming task performed at high speed. Ten adult subjects were required to aim at targets in various positions by making a punching movement with their hand. The experimental conditions were varied so that different parts of hand trajectory could be seen in the peripheral field. Two movement times were applied:  相似文献   
25.
The aim was to investigate mechanisms contributing to quercetin's previously described effects on cell-proliferation and -differentiation, which contradicted its proposed anticarcinogenic potency. In a 10-day experiment, 40 microM quercetin stabilized by 1 mM ascorbate reduced Caco-2 differentiation up to 50% (p < 0.001). Caco-2 RNA from days 5 and 10, hybridized on HG-U133A2.0 Affymetrix GeneChips(R), showed 1,743 affected genes on both days (p < 0.01). All 14 Caco-2 differentiation-associated genes showed decreased expression (p < 0.01), including intestinal alkaline phosphatase, that was confirmed technically (qRT-PCR) and functionally (enzyme-activity). The 1,743 genes contributed to 27 pathways (p < 0.05) categorized under six gene ontology (GO) processes, including apoptosis and cell-cycle. Genes within these GO-processes showed fold changes that suggest increased cell-survival and -proliferation. Furthermore, quercetin down-regulated expression of genes involved in tumor-suppression and phase II metabolism, and up-regulated oncogenes. Gene expression changes mediated by ascorbate-stabilized quercetin were concordant with those occurring in human colorectal carcinogenesis ( approximately 80-90%), but were opposite to those previously described for Caco-2 cells exposed to quercetin without ascorbate ( approximately 75-90%). In conclusion, gene expression among Caco-2 cells exposed to ascorbate-stabilized quercetin showed mechanisms contrary to what is expected for a cancer-preventive agent. Whether this unexpected in vitro effect is relevant in vivo, remains to be elucidated.  相似文献   
26.
27.
A framework for the development of an environmental management system that satisfies the requirements of the ISO 14001 standards is presented. The framework is developed for NB Power, a company producing electricity for the province of New Brunswick in Canada. A case study is carried out in a thermal power plant called Coleson Cove. An initial review of the existing environmental management programs is presented. The environmental policy is evaluated, and the environmental aspects and impacts of the plant's activities are identified and prioritized according to prespecified criteria of severity, frequency, degree of control, and existence of regulation. Environmental objectives and targets are set and recommendations are presented.  相似文献   
28.
This quasi-experimental study examined participation rates and sample characteristics of participants recruited with and without the offer of course credit. In Sample 1, where course credit is not usually offered, credit was added in one condition (N = 195) and not in the other (N = 175). In Sample 2, where credit is usually offered, it was maintained in one condition (N = 92) and removed in the other (N = 178). Results in both samples revealed that participation rates were higher in the credit conditions; they plunged when customary rewards were taken away. Results also revealed evidence of sample bias. More specifically, the motivational characteristics of participants and nonparticipants differed in all conditions except the new credit condition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
29.
The main objective of this paper is to analyse residential demand by traffic destination, using a translogarithmic indirect utility function. We focus on five traffic directions, in order to construct a model adapted to evaluate the characteristics of telecommunications demand in a competitive market. The resulting price elasticities express high reactivity to own price changes for the main traffic directions, as well as little interactions between the different types of traffic. Moreover, the high values of income elasticities confirm the importance of income effects when analysing residential telecommunications demand. This model shows useful for welfare analysis. The computation of customers' income equivalent variation shows, on average, a higher willingness to pay for some traffic directions than the bill actually paid. Finally, we show that the optimal prices for the operator, in a cost minimisation point of view, are higher than the observed prices for local and national traffic directions. This emphasises the existence of important cross-subsidies among the different segments of customers.  相似文献   
30.
Studied the effects of knowledge of results (KR), either spatial or temporal, on performance of a coincidence-timing task among Canadian children. Human subjects: 90 male and female Canadian children (aged 6–10 yrs). Ss were divided into 3 age groups (mean age 6.8 yrs, 8.3 yrs, and 10.2 yrs). Each age group was divided into 3 experimental groups: 1 group received spatial KR, 1 group received temporal KR, and 1 group received no KR during practice sessions for a coincidence-timing task. The task consisted of moving an object horizontally with the hand to a spot corresponding to the movement of a visual stimulus. The object was to reach the correct spot at the same time as the visual stimulus, which came from either the right or the left at speeds of 100 or 152 cm/s. The results were analyzed according to Ss' age, speed of stimulus, direction of stimulus, type of KR training, and whether or not the S's object arrived before or after the visual stimulus. A multivariate analysis of variance (MANOVA) was used. (English abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  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