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   2196篇
  免费   96篇
  国内免费   5篇
电工技术   37篇
综合类   6篇
化学工业   649篇
金属工艺   56篇
机械仪表   46篇
建筑科学   128篇
矿业工程   10篇
能源动力   46篇
轻工业   135篇
水利工程   9篇
无线电   148篇
一般工业技术   391篇
冶金工业   193篇
原子能技术   29篇
自动化技术   414篇
  2023年   19篇
  2022年   33篇
  2021年   66篇
  2020年   37篇
  2019年   38篇
  2018年   45篇
  2017年   42篇
  2016年   79篇
  2015年   58篇
  2014年   72篇
  2013年   103篇
  2012年   116篇
  2011年   149篇
  2010年   116篇
  2009年   104篇
  2008年   115篇
  2007年   97篇
  2006年   113篇
  2005年   80篇
  2004年   84篇
  2003年   55篇
  2002年   44篇
  2001年   43篇
  2000年   35篇
  1999年   38篇
  1998年   65篇
  1997年   56篇
  1996年   31篇
  1995年   24篇
  1994年   27篇
  1993年   26篇
  1992年   25篇
  1991年   21篇
  1990年   19篇
  1989年   15篇
  1988年   12篇
  1987年   15篇
  1986年   8篇
  1985年   13篇
  1984年   9篇
  1983年   11篇
  1982年   13篇
  1981年   12篇
  1980年   14篇
  1979年   11篇
  1978年   9篇
  1977年   10篇
  1976年   10篇
  1975年   14篇
  1974年   17篇
排序方式: 共有2297条查询结果,搜索用时 15 毫秒
1.
Wu  Li  Li  Jing  Fu  Caixia  Kühn  Bernd  Wang  Xiaolin 《Magma (New York, N.Y.)》2019,32(4):501-509
Magnetic Resonance Materials in Physics, Biology and Medicine - To investigate the value of using diffusion-weighted imaging (DWI) and intravoxel incoherent motion DWI (IVIM-DWI) to assess the...  相似文献   
2.
Metallurgical and Materials Transactions B - The quality requirements of aluminum products are steadily increasing, and the presence of non-metallic inclusions have a large impact on the quality of...  相似文献   
3.
We describe a novel, easy and efficient combinatorial phage display peptide substrate-mining method to map the substrate specificity of proteases. The peptide library is displayed on the pVII capsid of the M13 bacteriophage, which renders pIII necessary for infectivity and efficient retrieval, in an unmodified state. As capture module, the 3XFLAG was chosen due to its very high binding efficiency to anti-FLAG mAbs and its independency of any post-translational modification. This library was tested with Factor-VII activating protease (WT-FSAP) and its single-nucleotide polymorphism variant Marburg-I (MI)-FSAP. The WT-FSAP results confirmed the previously reported Arg/Lys centered FSAP cleavage site consensus as dominant, as well as reinforcing MI-FSAP as a loss-of-function mutant. Surprisingly, rare substrate clones devoid of basic amino acids were also identified. Indeed one of these peptides was cleaved as free peptide, thus suggesting a broader range of WT-FSAP substrates than previously anticipated.  相似文献   
4.
Abstract

Relative populations of four energy-lowest IPR (isolated-pentagon-rule) isomers of Eu@C86 are computed using the Gibbs energy based on characteristics from density functional theory calculations (M06-2X/3-21G?~?SDD entropy term, M06-2X/6-31G*~SDD or B2PLYP(D)/6-31G*~SDD energetics). The calculations confirm that the recently isolated Eu@C1(7)-C86 species is a major isomer in a relevant temperature region. Relationship to the empty C86 cages is discussed, too.  相似文献   
5.
6.
Non-standard fault models often require the application of two-pattern testing. A fully-automated approach for generating a multiple scan chain-based architecture is presented so that two-pattern test sets generated for the combinational core can be applied to the sequential circuit. Test time and area overhead constraints are considered.  相似文献   
7.
Security for ad hoc network environments has received a lot of attention as of today. Previous work has mainly been focussing on secure routing, fairness issues, and malicious node detection. However, the issue of introducing and conserving trust relationships has received considerably less attention. In this article, we present a scalable method for the use of public key certificates and their revocation in mobile ad hoc networks (MANETs). With the LKN-ad hoc security framework (LKN-ASF) a certificate management protocol has been introduced, bringing PKI technology to MANETs. In addition a performance analysis of two different revocation approaches for MANETs will be presented.  相似文献   
8.
The focus of this paper lies in the practical aspects of voice over IP communication. VoIP configurations in the H.323 standard will be presented briefly. Following that, the fundamental protocol procedure of H.323 communication will be briefly explained. A further part of the paper will address the subject QoS (quality of service), and present the common measurement methods used in QoS. Results gained from experiments conducted in a VoIP environment will then follow. The investigations concentrate primarily on the load behavior of voice packets in relation to important parameters of this service. The results obtained are presented and evaluated in diagrams. The paper concludes with a summary.  相似文献   
9.
New requirements of growing computer networks and information systems have an influence on extended client/server models with increased functionality. This forms the basis for service management in distributed systems which is realized by a service trading concept. This paper studies the requirements derived from the Open Distributed Processing (ODP) Reference Model in order to consider an open service market. Furthermore, it examines management possibilities for describing the service trading scenario. Because of similar architectures and properties ODP services, service offers, types, exporters and traders are mapped onto management components and modeled as managed objects. Therefore, the Guidelines for the Definition of Managed Objects (GDMO) are used. The final concept allows a precise and unambiguous study of the service trading scenario and provides means for exporting and importing of service offers in a distributed environment.  相似文献   
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