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   1279篇
  免费   97篇
电工技术   16篇
综合类   6篇
化学工业   355篇
金属工艺   30篇
机械仪表   35篇
建筑科学   63篇
矿业工程   2篇
能源动力   28篇
轻工业   250篇
水利工程   9篇
石油天然气   12篇
无线电   47篇
一般工业技术   181篇
冶金工业   169篇
原子能技术   5篇
自动化技术   168篇
  2024年   2篇
  2023年   11篇
  2022年   19篇
  2021年   68篇
  2020年   42篇
  2019年   52篇
  2018年   62篇
  2017年   59篇
  2016年   60篇
  2015年   58篇
  2014年   45篇
  2013年   88篇
  2012年   76篇
  2011年   94篇
  2010年   61篇
  2009年   78篇
  2008年   52篇
  2007年   50篇
  2006年   39篇
  2005年   41篇
  2004年   30篇
  2003年   16篇
  2002年   27篇
  2001年   17篇
  2000年   9篇
  1999年   15篇
  1998年   36篇
  1997年   30篇
  1996年   28篇
  1995年   17篇
  1994年   13篇
  1993年   15篇
  1992年   6篇
  1991年   5篇
  1990年   7篇
  1989年   4篇
  1988年   4篇
  1987年   5篇
  1985年   5篇
  1984年   3篇
  1982年   4篇
  1981年   2篇
  1979年   3篇
  1978年   2篇
  1977年   4篇
  1976年   5篇
  1975年   1篇
  1973年   1篇
  1963年   1篇
  1957年   1篇
排序方式: 共有1376条查询结果,搜索用时 31 毫秒
1.
2.
3.
4.
Antibiotics are potentially a cause of neurotoxicity in dialysis patients, the most common are the beta‐lactams as ceftazidime and cefepime, and few cases have been reported after piperacillin/tazobactam use. This report presents a case of a hypertensive and diabetic 67‐year‐old woman in regular hemodialysis, which previously had a stroke. She was hospitalized presenting pneumonia, which was initially treated with cefepime. Two days after treatment, she presented dysarthria, left hemiparesis, ataxia, and IX and X cranial nerves paresis. Computed tomography showed no acute lesions and cefepime neurotoxicity was hypothesized, and the antibiotic was replaced by piperacillin/tazobactam. The neurologic signs disappeared; however, 4 days after with piperacillin/tazobactam treatment, the neurological manifestations returned. A new computed tomography showed no new lesions, and the second antibiotic regimen withdrawn. After two hemodialysis sessions, the patient completely recovered from neurological manifestations. The patient presented sequentially neurotoxicity caused by two beta‐lactams antibiotics. This report meant to alert clinicians that these antibiotics have dangerous neurological effects in chronic kidney disease patients.  相似文献   
5.
Female SJL mice are more susceptible than male mice to experimental autoimmune encephalomyelitis (EAE) induced by myelin basic protein (MBP)-specific T lymphocytes. In the present study, we examined mechanisms involved in this gender-related difference in disease susceptibility. MBP-specific T lymphocytes derived from spleens of males during the effector phase of adoptive EAE produced significantly higher levels of IL-10, an anti-inflammatory cytokine in EAE. A protective effect of testosterone was then shown. Females implanted with dihydrotestosterone pellets demonstrated a significantly less severe course of EAE as compared with females implanted with placebo pellets. Finally, MBP-specific T lymphocytes derived from dihydrotestosterone-implanted females produced significantly higher levels of IL-10 than those from placebo. Together these data indicate that testosterone exerts a protective effect in EAE that is mediated at least in part by enhanced production of IL-10 by autoantigen-specific T lymphocytes.  相似文献   
6.
This paper assesses the impacts of a GTL plant on the expansion of Brazil's oil refining segment. The GTL plant (50,000 bpd) was sized to start up operations in 2015, producing diesel and naphtha through the indirect route (FT-synthesis). This plant will consume the non-associated natural gas production from the recent discoveries at the Santos Basin (around 419 Bm3), and the associated gas production from the Campos Basin. Both basins are located in the Southeast of Brazil, the most populated, rich and industrialized region of the country. Two different criteria for refinery expansion were simulated in order to meet oil product demand scenarios. Findings show that depending on the refinery expansion criteria considered GTL will play a fundamental hole to meet the oil product demand forecast to Brazil in the next 10 years.  相似文献   
7.
8.
A.V. Machado  M. van Duin 《Polymer》2005,46(17):6575-6586
Simple blending and dynamic vulcanisation of EPDM/PE blends using the resol/SnCl2 system was studied in an extruder using a series of sampling devices. The melting of the PE pellets occurs just in front of and in the first kneading zone. Upon complete melting of the PE phase, the EPDM/PE blends reach very quickly their final morphology. Crosslinking of the EPDM phase to high levels occurs already when the PE phase is not yet fully molten. The higher the EPDM content, the higher the viscous dissipation, the higher the melt temperature and, consequently, the higher the crosslinking rate. For the EPDM/PE (50/50; w/w) TPV a transition from continuous via co-continuous to fully dispersed EPDM is observed, which is driven by crosslinking. Although the degree of crosslinking of the EPDM rubber is very high, this does not prevent phase inversion of the blend. The EPDM/PE interface is rather blurred, because PE crystalline lamellae are growing into the EPDM domains, probably because of the high compatibility between PE and EPDM (60 wt% of ethene). This study shows that dynamic vulcanisation in extruders proceeds quite differently from that in batch kneaders, where melting, mixing and crosslinking are separated in time. In extruders mass and heat transport, melting of the thermoplastic, morphology development (including dispersion and phase inversion), distribution and dissolution of (crosslinking) chemicals and crosslinking of the rubber do not occur as independent phenomena, but mutually and/or continuously interact.  相似文献   
9.
10.
Studies on odor mixture perception suggest that although odor components can often be identified in mixtures, mixtures can also give rise to novel perceptual qualities that are not present in the components. Using an olfactory habituation task, the authors evaluated how the perceptual similarity between components in a mixture affects the perceptual quality of the mixture itself. Rats perceived binary mixtures composed of similar components as different from their 2 components, whereas binary mixtures composed of dissimilar components were perceived as very similar to their components. Results show that for both types of mixtures, pretraining to Component A reduces subsequent learning about Component B in rats trained in the presence of A. (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