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   219篇
  免费   28篇
电工技术   2篇
化学工业   45篇
金属工艺   2篇
机械仪表   9篇
建筑科学   15篇
能源动力   5篇
轻工业   44篇
水利工程   5篇
无线电   4篇
一般工业技术   34篇
冶金工业   55篇
自动化技术   27篇
  2023年   1篇
  2022年   4篇
  2021年   6篇
  2020年   8篇
  2019年   4篇
  2018年   14篇
  2017年   12篇
  2016年   13篇
  2015年   14篇
  2014年   10篇
  2013年   8篇
  2012年   11篇
  2011年   13篇
  2010年   10篇
  2009年   7篇
  2008年   6篇
  2007年   5篇
  2006年   2篇
  2005年   3篇
  2004年   4篇
  2003年   7篇
  2002年   5篇
  2001年   5篇
  1999年   2篇
  1998年   22篇
  1997年   13篇
  1996年   5篇
  1995年   7篇
  1994年   4篇
  1993年   3篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1985年   1篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1977年   1篇
  1976年   4篇
  1975年   2篇
  1973年   1篇
排序方式: 共有247条查询结果,搜索用时 9 毫秒
221.
Presentation of the case of one patient with a leiomyosarcoma of the spermatic cord with presence of numerous giant cells, a remarkably unusual finding. Presence of this type of cells, as well as their positivity for histiocytic markers in immunohistochemical staining, raise considerable problems for the differential diagnosis of this neoplasia with malignant fibrous histiocytomas, which probably requires a different, more aggressive therapeutical approach.  相似文献   
222.
223.
Motor behaviour relies on complex neurochemical interactions in the basal ganglia, in particular the striatum. Antagonistic influences in this region are exerted by afferent projections from, on the one hand, the ventral mesencephalon, utilizing dopamine as a transmitter, and, on the other hand, from the cerebral cortex, signalling by the excitatory amino acid glutamate. The activity in both these neuronal populations appears to be regulated by the neuropeptide cholecystokinin. This article concentrates on interactions between cholecystokinin and glutamate, summarizing some recent morphological, biochemical and behavioural findings. It is suggested that cholecystokinin, acting via the cholecystokininB receptor, potentiates the glutamatergic excitatory input to the striatum.  相似文献   
224.
Posterior fossa epidural hematomas: a review and synthesis   总被引:1,自引:0,他引:1  
The authors report three patients with posterior fossa epidural hematomas and analyze 80 additional cases in the accessible literature. They occur in the younger age groups with a clear male predominance (3.6 to 1). The loss of consciousness at the time of impact and just before surgical intervention have both proved to be factors indicating a poor prognosis. The clinical symptoms and signs were classified in three general types: increased intracranial pressure, brainstem dysfunction, and cerebellar disturbances. A fracture of the occipital bone was seen in 84.2% of the patients. The source of bleeding often remained undetermined, although a tear of the dural sinuses was a most frequent finding. An associated intracranial lesion was found in 39.7% of the cases, this being another factor indicating a poor prognosis. The overall mortality was 26.5%, while the surgical mortality was only 11.5%. Excellent results were achieved in 65% of the cases.  相似文献   
225.
This paper describes a pipelined parallel algorithm for the MMSE-OSIC decoding procedure proposed in V-BLAST wireless MIMO systems, for heterogeneous networks of processors. It is based on a block version of the square-root Kalman Filter algorithm that was initially devised to solve the RLS problem. It has been parallelized in a pipelined way obtaining a good efficiency and scalability. The optimum load balancing for this parallel algorithm is dynamic, but we derive a static load balancing scheme with good performance.  相似文献   
226.
The River Plate coastal plain is a 160‐km‐long, 3–10‐km‐wide strip, located to <5 m a.s.l. on the right bank of the estuary. It is formed by sediments and landforms generated by the littoral transport and marine ingressions and regressions during the Holocene. The coastal plain faces heavy pressures from Buenos Aires Metropolitan Area, with about 13 million inhabitants, industrial, mining and rural activities. Here, we analyse the relations existing between landforms, soils and vegetation. Despite the anthropogenic influence, the natural landscape is more or less preserved in some areas, such as patches of the southernmost gallery forest in the world in natural levees, the xerophytic forests located in well‐drained soils of beach ridges and other units such as Inland and Coastal Mudflats with wetland soils and vegetation, Tidal Flats with contrasting soils and plant communities among others.  相似文献   
227.
228.
Photocatalysis can be a useful tool in the treatment of some recalcitrant and toxic pollutants. In fact, it is being applied today in several industrial processes. However some problems arise in the modelling of photocatalytic systems, most of them related to the radiation field. In this work, some methods are presented which can be powerful tools in the evaluation of the radiation absorbed by the photocatalyst, which is the energy really useful in promoting the photocatalytic process. All these methods are based on actinometric procedures carried out in different experimental conditions and using different photoreactors.  相似文献   
229.
230.
Electrode structural stability and mechanical integrity is of major importance regarding not only lithium-ion battery performance but also safety aspects. The goal of this study is to design a simulation procedure to reproduce the microstructural and mechanical properties of such lithium-ion battery electrodes. Taking into consideration the particulate state of these electrodes, a discrete element method (DEM) approach is proposed, which comprises a procedure to reproduce real electrode structures and the application of a proper contact model to capture the bulk mechanics. This is accomplished by considering particle interactions as well as the performance of the binder. Three different electrodes are manufactured with the aim of calibrating and validating the Hertzian-bond contact model. Experimental nanoindentation measurements prove to be in good agreement with the simulation outcome, concluding that the method constitutes a valuable physical and mechanical basis for further applications.  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