首页 | 官方网站   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   78篇
  免费   4篇
工业技术   82篇
  2021年   1篇
  2020年   3篇
  2019年   2篇
  2018年   1篇
  2017年   2篇
  2016年   2篇
  2015年   1篇
  2014年   3篇
  2013年   2篇
  2011年   1篇
  2010年   2篇
  2009年   7篇
  2008年   3篇
  2007年   6篇
  2006年   5篇
  2005年   4篇
  2004年   7篇
  2002年   4篇
  2001年   2篇
  2000年   2篇
  1999年   5篇
  1998年   3篇
  1997年   3篇
  1996年   4篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1991年   1篇
  1990年   1篇
  1976年   1篇
  1973年   1篇
排序方式: 共有82条查询结果,搜索用时 158 毫秒
71.
We prospectively studied 100 consecutive patients (200 hands) sent to our Neurophysiopathology Service for a suspected Carpal Tunnel Syndrome (C.T.S.). We performed 6 different motor and sensitive electrodiagnostic tests on both hands of each patients and on 25 healthy subjects. We calculated the sensibility and the specificity of each test by comparing each parameter with all the other ones, and then, again, using the clinical evaluation as a "gold standard". The routinely performed tests proved to have a high sensibility in detecting C.T.S., nevertheless, sometimes they do not give a definite response. In these cases we suggest to carry out the neurophysiological examination by performing some of the newly proposed tests. We end our study by drawing a "flow-chart", which considers reliability, sensibility, difficulty in performing and/or evaluating, and discomfort for patients, of each test; by this we would give a guide and a practical aid in determining the electrophysiological path for C.T.S. diagnosis.  相似文献   
72.
73.
A new neural tree model, called adaptive high-order neural tree (AHNT), is proposed for classifying large sets of multidimensional patterns. The AHNT is built by recursively dividing the training set into subsets and by assigning each subset to a different child node. Each node is composed of a high-order perceptron (HOP) whose order is automatically tuned taking into account the complexity of the pattern set reaching that node. First-order nodes divide the input space with hyperplanes, while HOPs divide the input space arbitrarily, but at the expense of increased complexity. Experimental results demonstrate that the AHNT generalizes better than trees with homogeneous nodes, produces small trees and avoids the use of complex comparative statistical tests and/or a priori selection of large parameter sets.  相似文献   
74.
75.
This work describes the high temperature reaction sequence of commercial Man Made Vitreous Fibers (MMVF) Cerafiber, Superwool, Rock wool and Glass wool which may be used as substitute for asbestos in some industrial applications. Knowledge of the reaction path and transformation sequence is very important to assess whether carcinogenic crystalline phases are formed during devitrification, which may occur when used as insulators. In addition, knowledge about the nature of the phases formed at high temperature is mandatory to assess if thermally transformed MMVF can be safely recycled as secondary raw material (SRM). In this scenario, this study provides useful information for the optimization of the industrial annealing process aimed to attain a safe, recyclable product. The results of this work show that one of the high-temperature products of Cerafiber and Superwool is cristobalite which is classified as a carcinogenic. It was possible to define the temperature interval at which Cerafiber and Superwool fibers can be safely used as thermal insulators (e.g. insulators in tunnel and/or roller kilns, etc.). As cristobalite is formed in both synthetic fiber products at temperatures higher than 1200 degrees C, their use should be limited to devices operating at lower temperatures. Rock and Glass wool melt upon thermal treatment. As far as the industrial process of inertization is concerned, a maximum firing temperature of 1100 and 600 degrees C is required to melt Rock wool and Glass wool, respectively, with the high-temperature products that can be safely recycled as SRM. Recycling of these products in stoneware tile mixtures were subsequently attempted. The addition of 1-2 wt.% of the melts of Rock and Glass wool gave promising results in terms of viscous sintering reactions and resistance to staining with the only weak characteristic being the color properties of the fired bodies which tend to worsen.  相似文献   
76.
77.
Formaldehyde degradation in an anaerobic packed-bed bioreactor   总被引:2,自引:0,他引:2  
The development of appropriate technologies for the treatment of formaldehyde discharged into the environment is important to minimize its impact. Aerobic systems have been employed, although alternative anaerobic treatments have also been widely studied, mainly due to their low energy consumption and sludge production. However, toxic substances can lead to disturbances in anaerobic reactors. Some research has already been developed on formaldehyde anaerobic biological treatment, but no consensus has yet been reached about its behavior nor has the most efficient system been identified. Aiming at finding supporting evidence for this issue, therefore, this study investigated the degradation and toxicity of formaldehyde in a Horizontal-Flow Anaerobic Immobilized Sludge Reactor. Formaldehyde concentrations of 26.2-1158.6 mg HCHO/L were applied in the reactor, resulting in formaldehyde and chemical oxygen demand removal efficiencies of 99.7% and 92%, respectively. Volatile fatty acids with up to five carbons, found during the degradation of formaldehyde, are believed to indicate that the degradation followed routes unlike those suggested in the literature, which reports the formation of intermediates such as methanol and formic acid. The Monod kinetic model adhered to the experimental data well, with apparent kinetic parameters estimated as r(app)max) = 2.79 x 10(-3) mg HCHO/mg SSVh and K (app)(s) = 242.8 mg HCHO/L.  相似文献   
78.
This work reports on the influence of the agitation rate on the organic matter degradation in an anaerobic sequencing batch reactor, containing biomass immobilized on 3 cm cubic polyurethane matrices, stirred mechanically and fed with partially soluble soymilk substrate with mean chemical oxygen demand (COD) of 974+/-70 mg l(-1). Hydrodynamic studies informed on the homogenization time under agitagion rates from 500 to 1100 rpm provided by three propeller impellers. It occurred very quickly compared to the total cycle time. The results showed that agitation provided good mixing and improved the overall organic matter consumption rates. A modified first-order kinetic model represented adequately the data in the entire range of agitation rate. The apparent first-order kinetic constant for suspended COD rose approximately 360% when the agitation rate was changed from 500 to 900 rpm, whereas the apparent first-order kinetic constant for soluble COD did not vary significantly.  相似文献   
79.
A distributed optimization framework and its application to the regulation of the behavior of a network of interacting image processing algorithms are presented. The algorithm parameters used to regulate information extraction are explicitly represented as state variables associated with all network nodes. Nodes are also provided with message-passing procedures to represent dependences between parameter settings at adjacent levels. The regulation problem is defined as a joint-probability maximization of a conditional probabilistic measure evaluated over the space of possible configurations of the whole set of state variables (i.e., parameters). The global optimization problem is partitioned and solved in a distributed way, by considering local probabilistic measures for selecting and estimating the parameters related to specific algorithms used within the network. The problem representation allows a spatially varying tuning of parameters, depending on the different informative contents of the subareas of an image. An application of the proposed approach to an image processing problem is described. The processing chain chosen as an example consists of four modules. The first three algorithms correspond to network nodes. The topmost node is devoted to integrating information derived from applying different parameter settings to the algorithms of the chain. The nodes associated with data-transformation processes to be regulated are represented by an optical sensor and two filtering units (for edge-preserving and edge-extracting filterings), and a straight-segment detection module is used as an integration site.  相似文献   
80.
OBJECTIVE: To evaluate the clinical and therapeutic efficacy of 2% clindamycin vaginal cream in pregnant women heavily colonized with group B streptococci (GBS). STUDY DESIGN: A prospective, clinical trial in which carriers of group B streptococci were randomized to receive topical intravaginal clindamycin or oral amoxicillin. PATIENTS: We randomized 105 pregnant women: 55 received 2% clindamycin vaginal cream (100 mg/day for 7 days) and 50 oral amoxicillin (2 g/day for 7 days). INTERVENTIONS: Patients were treated during pregnancy, none of them received intrapartum chemoprophylaxis. On the other hand, all the neonates, within 24 hours from delivery, were studied from the microbiological point of view, carrying out auricolar, nasal, oropharyngeal and umbilical cultures. RELIEFS: The eradication of the microorganism was evaluated by performing a vaginal culture after 6 weeks from the beginning of antibiotic therapy. RESULTS: The eradication rate of the microorganism was significantly higher in women treated with topical clindamycin compared with the group receiving oral amoxicillin (71% versus 36%; p < 0.05). The neonatal outcome was similar in the two groups in terms of gestational age at delivery and mean birthweight. None of the neonates was admitted to the neonatal intensive care unit and no cases of neonatal sepsis were recorded. CONCLUSIONS: From our experience we can conclude that, during pregnancy, a treatment with topical intravaginal clindamycin may be useful in the eradication of GBS.  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-23

京公网安备 11010802026262号