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   245篇
  免费   5篇
  国内免费   1篇
化学   124篇
晶体学   3篇
数学   60篇
物理学   9篇
无线电   55篇
  2023年   1篇
  2022年   2篇
  2021年   6篇
  2020年   4篇
  2019年   5篇
  2018年   9篇
  2017年   3篇
  2016年   8篇
  2015年   5篇
  2014年   11篇
  2013年   25篇
  2012年   17篇
  2011年   10篇
  2010年   9篇
  2009年   16篇
  2008年   8篇
  2007年   21篇
  2006年   12篇
  2005年   9篇
  2004年   4篇
  2003年   2篇
  2002年   9篇
  2000年   2篇
  1999年   4篇
  1998年   1篇
  1997年   4篇
  1996年   1篇
  1995年   2篇
  1994年   3篇
  1992年   2篇
  1989年   2篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   2篇
  1983年   5篇
  1982年   1篇
  1981年   7篇
  1980年   4篇
  1979年   8篇
  1976年   2篇
排序方式: 共有251条查询结果,搜索用时 15 毫秒
181.
182.
In this paper we introduce the notions of [I N] and [S I N]-hypergroups and prove a Choquet-Deny type theorem for [I N] and central hypergroups. More precisely, we prove a Liouville theorem for bounded harmonic functions on a class of [I N]-hypergroups. Further, we show that positive harmonic functions on [I N]-hypergroups are integrals of exponential functions. Similar results are proved for [S I N] and central hypergroups.  相似文献   
183.
We develop a model theoretic framework for studying algebraic structures equipped with a measure. The real line is used as a value space and its usual arithmetical operations as connectives. Integration is used as a quantifier. We extend some basic results of pure model theory to this context and characterize measurable sets in terms of zero-sets of formulas.   相似文献   
184.
CD.-Based Configurational Assignments of Glycosylaziridines The relationship between CD.-curves and the configuration of the trans-2-benzoyl-3-phenylaziridines was known. By studying a series of cis- and trans-2-glycosyl-3-benzoylaziridines we have shown that CD. allows the assignment of the configuration at both asymetric C-atoms. As benzoylaziridines can easily be obtained from cyano- or alkoxycarbonylaziridines without configurational change, the absolute configuration of these last two classes of compounds can also be assessed by this method.  相似文献   
185.
186.
The goal of this work was to simulate the effect of the finite conductivity of semiconductor substrates on the on-chip coupling inductance and then to investigate the effect of the on-chip coupling inductance on circuit crosstalk. In addition, the limitations of standard approaches for estimating coupling inductance are examined. A method for the reduction of the coupling inductance and its effect on circuit crosstalk is also discussed.  相似文献   
187.
188.
the extraction behavior of certain tervalent lanthanides into chloroform solutions containing various N-phenylacylhydroxamic acids is reported. The ligands include N-o-methylphenyl-m-trifluoromethylbenzohydroxamic acid (MPFBHA), N-m-trifuloromethylphenyl-o-methylbenzohydroxamic acid (FPMBHA), N-o-methylphenylbenzohydroxamic acid (MPBHA), N-phenyl-o-methylbenzohydroxamic acid (PMBHA), N-o-methylphenyl-p-tertbutylbenzohydroxamic acid (MPBBHA), and N-phenyl-p-tert-butylbenzohydroxamic acid (PBBHA). Of the N-phenylacylhydroxamic acids mentioned, only PBBHA was found suitable to extract the lanthanides under the experimental conditions used. The selected lanthanides, namely La, Pr, Eu, Ho, and Yb, were all found to extract with PBBHA as self-adducts of the form LnL3 · 2 HL, where L and HL denote the ligand anion and neutral ligand, respectively. The extraction constants and separation factors for the lanthanides with PBBHA were evaluated. It is possible that steric hindrance prevents the lanthanides from extracting with MPFBHA, FPMBHA, MPBHA, PMBHA, or MPBBHA.  相似文献   
189.
This paper presents a detailed scaling analysis of the power supply distribution network voltage drop in DSM technologies. The effects of chip temperature, electromigration and interconnect technology scaling (including resistivity increase of Cu interconnects due to electron surface scattering and finite barrier thickness) are taken into consideration during this analysis. It is shown that the voltage drop effect in the power/ground (P/G) distribution network increases rapidly with technology scaling, and that using well-known countermeasures such as wire-sizing and/or decoupling capacitor insertion which are typically used in the present design methodologies may be insufficient to limit the voltage fluctuations over the power grid for future technologies. It is also shown that such voltage drops on power supply lines of switching devices in a clock distribution network can introduce significant amount of skew which in turn degrades the signal integrity.This work was done when the author was with the Dept. of EESystems, University of Southern California.Amir H. Ajami received his B.S. degree in electrical engineering from the University of Tehran, Tehran, Iran in 1993. He received his M.S. and Ph.D. degrees in electrical engineering from the University of Southern California, Los Angeles, CA, in 1999 and 2002, respectively.He is currently a member of consulting staff in research and development division at MagmaDesign Automation, Inc., Santa Clara, CA. He has previously held positions at Cadence Design Systems, Inc., andMagma Design Automations, Inc., in 1999 and 2000, respectively. His research interests are in the area of technology scaling issues in high-performance VLSI designs with emphasis on full-chip thermal analysis, thermalaware timing and power optimization methodologies, and signal integrity. He has coauthored several papers on the modeling and analysis of the effects of substrate thermal gradients on performance degradation and development of thermal-aware physical-synthesis optimization algorithms.Dr. Ajami is a member of Association of Computing Machinery (ACM) and IEEE. HE serves on the technical program committee of the 2005 IEEE International Symposium on Quality Electronics Design.Kaustav Banerjee received the Ph.D. degree in electrical engineering and computer sciences from the University of California at Berkeley in 1999. He was with Stanford University, Stanford, CA, from 1999 to 2002 as a Research Associate at the Center for Integrated Systems. In July 2002, he joined the faculty of the Electrical and Computer Engineering Department at the University of California, Santa Barbara, as an Assistant Professor. From February 2002 to August 2002 he was a Visiting Professor at the Circuit Research Labs of Intel in Hillsboro, Oregon. In the past, he has also held summer/visiting positions at Texas Instruments Inc., Dallas, Texas, Fujitsu Labs and the Swiss Federal Institute of Technology (EPFL). His present research interests focus on a wide variety of nanometer scale issues in high-performance VLSI and mixed-signal designs, as well as on circuits and systems issues in emerging nanoelectronics. He is also interested in some exploratory interconnect and circuit architectures including 3-D ICs. At UCSB, Dr. Banerjee mentors several doctoral and masters students. He also co-advises graduate students at Stanford University, University of Illinois at Urbana-Champaign and EPFL-Switzerland. He has co-directed two doctoral dissertations at Stanford University and the University of Southern California. Dr. Banerjee served as Technical Program Chair of the 2002 IEEE International Symposium on Quality Electronic Design (ISQED 02), and is the General Chair of ISQED 05. He also serves or has served on the technical program committees of the IEEE International Electron Devices Meeting, the IEEE International Reliability Physics Symposium, the EOS/ESD Symposium and the ACM International Symposium on Physical Design. His research has been chronicled in over 100 journals and refereed international conference papers and a book chapter. He has also co-edited a book titled Emerging Nanoelectronics: Life with and after CMOS by Kluwer in 2004. Dr. Banerjee has been recognized through the ACM SIGDA Outstanding New Faculty Award (2004) as well as a Best Paper Award at the Design Automation Conference (2001). He is listed in Whos Who in America and Whos Who in Science and Engineering.Massoud Pedram received a B.S. degree in Electrical Engineering from the California Institute of Technology in 1986 and M.S. and Ph.D. degrees in Electrical Engineering and Computer Sciences from the University of California, Berkeley in 1989 and 1991, respectively. He then joined the department of Electrical Engineering, Systems at the University of Southern California where he is currently a professor. Dr. Pedram has served on the technical program committee of a number of conferences, including the Design automation Conference (DAC), Design and Test in Europe Conference (DATE), Asia-Pacific Design automation Conference (ASP-DAC), and International Conference on Computer Aided Design (ICCAD). He served as the Technical Co-chair and General Co-chair of the International Symposium on Low Power Electronics and Design (SLPED) in 1996 and 1997, respectively. He was the Technical Program Chair and the General Chair of the 2002 and 2003 International Symposium on Physical Design. Dr. Pedram has published four books, 60 journal papers, and more than 150 conference papers. His research has received a number of awards including two ICCD Best Paper Awards, a Distinguished Citation from ICCAD, a DAC Best Paper Award, and an IEEE Transactions on VLSI Systems Best Paper Award. He is a recipient of the NSFs Young Investigator Award (1994) and the Presidential Faculty Fellows Award (a.k.a. PECASE Award) (1996).Dr. Pedram is a Fellow of the IEEE, a member of the Board of Governors for the IEEE Circuits and systems Society, an associate editor of the IEEE Transactions on Computer Aided Design, the IEEE Transactions on Circuits and Systems, and the IEEE Circuits and Systems Society Distinguished Lecturer Program Chair. He is also an Advisory Board Member of the ACM Interest Group on Design Automation, and an associate editor of the ACM Transactions on Design Automation of Electronic Systems. His current work focuses on developing computer aided design methodologies and techniques for low power design, synthesis, and physical design. For more information, please go to URL address: .  相似文献   
190.
A combined iterative force field—CNDO molecular orbital approach to conformations of methylcyclooctane is described. This hybrid method involves a full relaxation force-field calculation of conformer structures, followed by a single CNDO calculation on each structure.  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