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   2150篇
  免费   34篇
电工技术   7篇
综合类   1篇
化学工业   131篇
金属工艺   12篇
机械仪表   14篇
建筑科学   18篇
矿业工程   3篇
能源动力   19篇
轻工业   75篇
水利工程   7篇
石油天然气   4篇
无线电   34篇
一般工业技术   108篇
冶金工业   1676篇
原子能技术   2篇
自动化技术   73篇
  2023年   5篇
  2022年   12篇
  2021年   44篇
  2020年   22篇
  2019年   14篇
  2018年   27篇
  2017年   27篇
  2016年   19篇
  2015年   13篇
  2014年   28篇
  2013年   27篇
  2012年   40篇
  2011年   39篇
  2010年   27篇
  2009年   34篇
  2008年   19篇
  2007年   18篇
  2006年   13篇
  2005年   14篇
  2004年   13篇
  2003年   11篇
  2002年   8篇
  2001年   4篇
  2000年   3篇
  1999年   52篇
  1998年   499篇
  1997年   283篇
  1996年   202篇
  1995年   108篇
  1994年   107篇
  1993年   101篇
  1992年   19篇
  1991年   32篇
  1990年   25篇
  1989年   21篇
  1988年   25篇
  1987年   23篇
  1986年   21篇
  1985年   20篇
  1983年   5篇
  1982年   11篇
  1981年   9篇
  1980年   11篇
  1979年   1篇
  1978年   4篇
  1977年   33篇
  1976年   84篇
  1975年   5篇
  1974年   1篇
  1955年   1篇
排序方式: 共有2184条查询结果,搜索用时 0 毫秒
1.

Both water balance (WB) and rating curve (RC) are methods for estimating streamflow. The first is mostly used to estimate reservoir outflows, while the second is usually adopted in hydrometeorological network streamflow gauges. While WB uses hourly collected data, the RC estimates streamflow using current water level and extrapolation techniques. The objective of this study was to analyze variations in the reservoir’s hourly outflow at Queimado Hydroelectric Power Plant (HPP Queimado) and to propose a method to evaluate whether the estimate of the daily outflows, obtained by the WB method, is similar to the flow values obtained at a conventional station. The logistic regression (LR) model was used because it is a method that adopts binary, categorically dependent variables to identify the event of interest. The results showed that the values of streamflow, obtained from an average of two daily readings, were a good representation of the flows in the region. The LR was able to identify atypical data, especially in the rainy season. This means that data consistency analysis can be faster and safer, when adequately employed and considering the proposed conditions, contributing to both management policies and the management of water resources.

  相似文献   
2.
Computer‐Interpretable Guidelines (CIGs) are the dominant medium for the delivery of clinical decision support, given the evidence‐based nature of their source material. Therefore, these machine‐readable versions have the ability to improve practitioner performance and conformance to standards, with availability at the point and time of care. The formalisation of Clinical Practice Guideline knowledge in a machine‐readable format is a crucial task to make it suitable for the integration in Clinical Decision Support Systems. However, the current tools for this purpose reveal shortcomings with respect to their ease of use and the support offered during CIG acquisition and editing. In this work, we characterise the current landscape of CIG acquisition tools based on the properties of guideline visualisation, organisation, simplicity, automation, manipulation of knowledge elements, and guideline storage and dissemination. Additionally, we describe the CompGuide Editor, a tool for the acquisition of CIGs in the CompGuide model for Clinical Practice Guidelines that also allows the editing of previously encoded guidelines. The Editor guides the users throughout the process of guideline encoding and does not require proficiency in any programming language. The features of the CIG encoding process are revealed through a comparison with already established tools for CIG acquisition.  相似文献   
3.
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   
4.
5.
6.
Tumor cells from eight freshly isolated cervical cancers (i.e., four adenocarcinomas and four squamous carcinomas) were analyzed for their production of the immune-inhibitory cytokine transforming growth factor-beta (TGF-beta) in vitro. All fresh adenocarcinomas secreted significant levels of TGF-beta (mean 397, range between 207 and 782 pg/ml/10(5) cells/48 hr). In contrast, no detectable TGF-beta was present in the supernatants from the four fresh squamous carcinoma cultures (P < 0.001). These data suggest that major differences in the secretion of the immunoinhibitory cytokine TGF-beta exist between squamous cell carcinomas and adenocarcinomas of the uterine cervix. Furthermore, these findings suggest that at least some of the differences in the natural biologic behavior, as well as in the response to radiation treatment, between these two histologic types of cervical cancer could be related to differences in secretion of this immune-inhibitory cytokine.  相似文献   
7.
8.
9.
10.
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