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   9427篇
  免费   1659篇
  国内免费   521篇
电工技术   85篇
综合类   336篇
化学工业   395篇
金属工艺   72篇
机械仪表   155篇
建筑科学   84篇
矿业工程   29篇
能源动力   142篇
轻工业   504篇
水利工程   26篇
石油天然气   25篇
武器工业   23篇
无线电   1185篇
一般工业技术   300篇
冶金工业   33篇
原子能技术   79篇
自动化技术   8134篇
  2025年   48篇
  2024年   501篇
  2023年   396篇
  2022年   345篇
  2021年   542篇
  2020年   358篇
  2019年   295篇
  2018年   326篇
  2017年   627篇
  2016年   521篇
  2015年   536篇
  2014年   827篇
  2013年   614篇
  2012年   696篇
  2011年   692篇
  2010年   581篇
  2009年   649篇
  2008年   527篇
  2007年   606篇
  2006年   573篇
  2005年   337篇
  2004年   95篇
  2003年   126篇
  2002年   99篇
  2001年   81篇
  2000年   108篇
  1999年   79篇
  1998年   52篇
  1997年   41篇
  1996年   36篇
  1995年   16篇
  1994年   17篇
  1993年   15篇
  1992年   14篇
  1991年   10篇
  1990年   11篇
  1989年   6篇
  1988年   31篇
  1987年   36篇
  1986年   51篇
  1985年   4篇
  1984年   7篇
  1983年   4篇
  1981年   9篇
  1979年   5篇
  1974年   4篇
  1972年   5篇
  1968年   4篇
  1967年   5篇
  1965年   6篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
In this paper, a new methodology is presented for topology optimization of networked embedded systems as they occur in automotive and avionic systems as well as wireless sensor networks. By introducing a model which is (1) suitable for heterogeneous networks with different communication bandwidths, (2) modeling of routing restrictions, and (3) flexible binding of tasks onto processors, current design issues of networked embedded systems can be investigated. On the basis of this model, the presented methodology firstly allocates the required resources which can be communication links as well as computational nodes and secondly binds the functionality onto the nodes and the data dependencies onto the links such that no routing restrictions will be violated or capacities on communication links will be exceeded. Due to the often error-prone communication in networks, we allow for routing each data dependency over multiple routes in the networks. With this strategy, our methodology is able to increase the reliability of the entire system. This reliability analysis is based on Binary Decision Diagrams (BDDs) and is integrated in our multi-objective design space exploration. By applying Evolutionary Algorithms, we are able to consider multiple objectives simultaneously during the optimization process and allow for a subsequent unbiased decision making. An experimental evaluation as well as a demonstration of a case study from the field of automotive electronics will show the applicability of the presented approach.  相似文献   
2.
Turning the free edge of an unstiffened flange inwards or outwards to form a ‘lip’, can substantially improve the local buckling resistance of a member. The lip is the most common type of edge stiffener used in cold-rolled, thin-walled sections. In this paper the behaviour of plate elements of thin-walled sections stiffened by compound lips (i.e. lips which are folded twice to form ‘lips on the lips’) is examined both theoretically and experimentally. An outline of a series of tests on compound edge-stiffened thin-walled sections of various geometries is given and some load-end compression displacement paths are compared with the theoretical predictions. Reasonably good agreement is obtained between the experimental and theoretical results. Comparisons of the theoretical predictions with experimental results of other researchers are also presented in this paper.  相似文献   
3.
Harmful algal blooms, which are considered a serious environmental problem nowadays, occur in coastal waters in many parts of the world. They cause acute ecological damage and ensuing economic losses, due to fish kills and shellfish poisoning as well as public health threats posed by toxic blooms. Recently, data-driven models including machine-learning (ML) techniques have been employed to mimic dynamics of algal blooms. One of the most important steps in the application of a ML technique is the selection of significant model input variables. In the present paper, we use two extensively used ML techniques, artificial neural networks (ANN) and genetic programming (GP) for selecting the significant input variables. The efficacy of these techniques is first demonstrated on a test problem with known dependence and then they are applied to a real-world case study of water quality data from Tolo Harbour, Hong Kong. These ML techniques overcome some of the limitations of the currently used techniques for input variable selection, a review of which is also presented. The interpretation of the weights of the trained ANN and the GP evolved equations demonstrate their ability to identify the ecologically significant variables precisely. The significant variables suggested by the ML techniques also indicate chlorophyll-a (Chl-a) itself to be the most significant input in predicting the algal blooms, suggesting an auto-regressive nature or persistence in the algal bloom dynamics, which may be related to the long flushing time in the semi-enclosed coastal waters. The study also confirms the previous understanding that the algal blooms in coastal waters of Hong Kong often occur with a life cycle of the order of 1–2 weeks.  相似文献   
4.
5.
One of the critical security issues of Vehicular Ad Hoc Networks (VANETs) is the revocation of misbehaving vehicles. While essential, revocation checking can leak potentially sensitive information. Road Side Units (RSUs) receiving the certificate status queries could infer the identity of the vehicles posing the query. An important loss of privacy results from the RSUs ability to tie the checking vehicle with the query's target. We propose a Privacy Preserving Revocation mechanism (PPREM) based on a universal one-way accumulator. PPREM provides explicit, concise, authenticated and unforgeable information about the revocation status of each certificate while preserving the users' privacy.  相似文献   
6.
7.
8.
In this article, with Ehrenfeucht-Fraïssé games we prove that Δ1Δ0 on BFR, which implies ΔΔ0 on BFR, and thus solve an open problem raised by Albert Atserias in his dissertation (Δ0,Δ1,Δ are fragments of first order logic and BFR is a class of finite sets which in essence is equivalent to a class of finite pure arithmetic structures with built-in BIT predicate).  相似文献   
9.
10.
Lin  Yijun  Wu  Fengge  Zhao  Junsuo 《Neural computing & applications》2023,35(11):8227-8241
Neural Computing and Applications - High-resolution (HR) remote sensing images provide rich information for human activities. However, processing entire HR images is time-consuming, and many...  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