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   2026篇
  免费   74篇
  国内免费   5篇
电工技术   36篇
综合类   6篇
化学工业   626篇
金属工艺   54篇
机械仪表   44篇
建筑科学   125篇
矿业工程   9篇
能源动力   46篇
轻工业   132篇
水利工程   5篇
无线电   132篇
一般工业技术   362篇
冶金工业   114篇
原子能技术   28篇
自动化技术   386篇
  2023年   20篇
  2022年   35篇
  2021年   66篇
  2020年   34篇
  2019年   35篇
  2018年   37篇
  2017年   38篇
  2016年   72篇
  2015年   53篇
  2014年   63篇
  2013年   93篇
  2012年   112篇
  2011年   144篇
  2010年   113篇
  2009年   95篇
  2008年   111篇
  2007年   94篇
  2006年   109篇
  2005年   75篇
  2004年   76篇
  2003年   49篇
  2002年   42篇
  2001年   40篇
  2000年   33篇
  1999年   37篇
  1998年   38篇
  1997年   33篇
  1996年   24篇
  1995年   22篇
  1994年   24篇
  1993年   20篇
  1992年   22篇
  1991年   21篇
  1990年   16篇
  1989年   15篇
  1988年   10篇
  1987年   14篇
  1985年   13篇
  1984年   9篇
  1983年   11篇
  1982年   12篇
  1981年   11篇
  1980年   13篇
  1979年   11篇
  1978年   9篇
  1977年   10篇
  1976年   8篇
  1975年   14篇
  1974年   16篇
  1973年   7篇
排序方式: 共有2105条查询结果,搜索用时 31 毫秒
181.
Heart rate variability (HRV) represents the cardiovascular control mediated by the autonomic nervous system and other mechanisms. In the established task force HRV monitoring different cardiovascular control mechanisms can approximately be identified at typical frequencies of heart rate oscillations by power spectral analysis. HRV measures assessing complex and fractal behavior partly improved clinical risk stratification. However, their relationship to (patho-)physiology is not sufficiently explored. Objective of the present work is the introduction of complexity measures of different physiologically relevant time scales. This is achieved by a new concept of the autonomic information flow (AIF) analysis which was designed according to task force HRV. First applications show that different time scales of AIF improve the risk stratification of patients with multiple organ dysfunction syndrome and cardiac arrest patients in comparison to standard HRV. Each group's significant time scales correspond to their respective pathomechanisms.  相似文献   
182.
183.
The standardization of processes and the identification of shared business services in a service-oriented architecture (SOA) are currently widely discussed. Above all in practice, however, there still is a lack of appropriate instruments to support these tasks. In this paper an approach for a process map is introduced which allows for a systematic presentation—as complete as possible—of the processes in an enterprise (division). After a consistent refinement of the process has taken place by means of aggregation/disaggregation respectively, generalization/specialization relations, it is possible to identify primarily functional similarities of the detailed sub-processes. The application of the process map at a financial service provider (FSP) highlights how these similarities can be taken as a basis to standardize processes and to identify shared services.  相似文献   
184.
185.
In this paper an image data compression scheme based on Periodic Haar Piecewise-Linear (PHL) transform and quantization tables is proposed. Effectiveness of the compression for different classes of images is evaluated. The comparison of the compression quality using PHL and DCT transforms is given.  相似文献   
186.
Revolute joints in applications always show clearance between pin and bushing due to manufacturing tolerances, the need of relative motion or progressing wear. Many researchers developed and investigated methodologies to calculate the dynamic behavior of mechanisms with such imperfect joints. Very often they use a simple slider-crank mechanism to test or demonstrate the capability of their approaches. In this paper, a methodology for simulating a slider-crank mechanism with an imperfect revolute joint in RecurDyn, a commercial multibody simulation tool, is presented. Therefore, a thorough investigation of existing contact, damping and friction force models as well as different ways of modeling revolute joints in RecurDyn was conducted. For the investigation of the damping models, a special program for calculating the model parameters for a given coefficient of restitution was developed. Only one damping model was capable of reproducing the experimental results, which were found in literature. Some characteristic results of the slider-crank mechanism are presented in a way that they can be compared to results in other papers. Thereby. a good correlation was achieved, demonstrating the capabilities of the methodology.  相似文献   
187.
We consider the distributed realizability problem for systems with regular and deterministic contextfree local specifications. We characterize exactly the architectures for which the realizability problem is decidable. This extends known results on local specifications in two directions. First, architectures with cycles are allowed instead of just acyclic ones and second, deterministic contextfree specifications are considered.  相似文献   
188.
189.
Wendelstein 7-X is an advanced helical stellarator, which is presently under construction at the Greifswald branch of IPP. A set of 70 superconducting coils arranged in five modules provides a twisted shaped magnetic cage for the plasma and allows steady state operation. Operation of the magnet system at cryogenic temperatures requires a cryostat which provides thermal protection and gives access to the plasma. The main components of the cryostat are the plasma vessel, the outer vessel, the ports, and the thermal insulation. The German company, MAN Diesel & Turbo SE Deggendorf (former MAN DWE GmbH Deggendorf), is responsible for the manufacture and assembly of the plasma vessel, the outer vessel and the thermal insulation. This paper describes the manufacturing and assembly technology of the plasma and outer vessel of the cryostat for Wendelstein 7-X.  相似文献   
190.
A generating extension of a program specializes the program with respect to part of the input. Applying a partial evaluator to the program trivially yields a generating extension, but specializing the partial evaluator with respect to the program often yields a more efficient one. This specialization can be carried out by the partial evaluator itself; in this case, the process is known as the second Futamura projection.We derive an ML implementation of the second Futamura projection for Type-Directed Partial Evaluation (TDPE). Due to the differences between traditional, syntax-directed partial evaluation and TDPE, this derivation involves several conceptual and technical steps. These include a suitable formulation of the second Futamura projection and techniques for making TDPE amenable to self-application. In the context of the second Futamura projection, we also compare and relate TDPE with conventional off-line partial evaluation.We demonstrate our technique with several examples, including compiler generation for Tiny, a prototypical imperative language.  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