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   2321篇
  免费   129篇
  国内免费   3篇
电工技术   16篇
化学工业   548篇
金属工艺   62篇
机械仪表   40篇
建筑科学   83篇
矿业工程   5篇
能源动力   58篇
轻工业   201篇
水利工程   9篇
石油天然气   3篇
无线电   251篇
一般工业技术   427篇
冶金工业   274篇
原子能技术   32篇
自动化技术   444篇
  2023年   26篇
  2022年   39篇
  2021年   42篇
  2020年   52篇
  2019年   57篇
  2018年   59篇
  2017年   68篇
  2016年   75篇
  2015年   63篇
  2014年   76篇
  2013年   139篇
  2012年   127篇
  2011年   167篇
  2010年   117篇
  2009年   111篇
  2008年   123篇
  2007年   110篇
  2006年   100篇
  2005年   87篇
  2004年   78篇
  2003年   67篇
  2002年   64篇
  2001年   30篇
  2000年   28篇
  1999年   35篇
  1998年   76篇
  1997年   65篇
  1996年   41篇
  1995年   35篇
  1994年   32篇
  1993年   39篇
  1992年   24篇
  1991年   12篇
  1990年   13篇
  1989年   9篇
  1988年   11篇
  1987年   8篇
  1986年   6篇
  1985年   13篇
  1984年   15篇
  1983年   13篇
  1982年   13篇
  1981年   8篇
  1980年   5篇
  1978年   5篇
  1977年   10篇
  1976年   15篇
  1975年   6篇
  1956年   4篇
  1935年   3篇
排序方式: 共有2453条查询结果,搜索用时 15 毫秒
1.
An antibacterial peptide (AMP), i.e., nisin, was covalently bound to gelatin through a protein–protein coupling. Various reaction conditions were tested to study and optimize parameters of grafting e.g., orientation and density of AMP, which could impact the final antibacterial activity of the modified biopolymer. Modification was investigated by Fourier transform infrared (FT‐IR) spectroscopy and zeta potential. The antibacterial activity of the nisin‐enriched gelatin was evaluated against two staphylococci bacterial strains, i.e., Staphylococus epidermidis and Staphylococcus aureus. A higher activity was found for gelatin modified at pH = 7.4 revealing an influence of the nisin orientation on the protein antibacterial property. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41825.  相似文献   
2.
Computer Supported Cooperative Work (CSCW) -  相似文献   
3.
4.
5.
The authors describe their scientific and clinical interests in developing the panel Trauma, Dissociation, and Conflict: The Space Where Neuroscience, Cognitive Science, and Psychoanalysis Overlap, given at the 22nd Annual Spring Meeting of the Division of Psychoanalysis of the American Psychological Association. They cite the influence of the panelists, Philip M. Bromberg, Wilma Bucci, and Joseph LeDoux, on their own work. Specializing in the treatment of chronic pain, Anderson has developed a relational intersubjective technique informed by this interdisciplinary approach. Gold's work has focused on the distinction between dissociative processes and repression in traumatic memory. The relevance of trauma, dissociation, and conflict, heightened since September 11, 2001, could not have been anticipated in the planning of the panel. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
6.
We study experimentally and theoretically two polarization effects in a vertical cavity surface emitting laser submitted to optical feedback. In a first experiment, we obtain flips between two linearly polarized laser modes up to a frequency of 50 MHz using an external cavity with a polarizer. In a second experiment, polarization self modulation is demonstrated up to a frequency of 2.6 GHz, using a quarter wave plate instead. Numerical calculations, based on a four levels model for the active medium, show a good agreement with the experiments.  相似文献   
7.
Summary Considered in this paper is the two-dimensional steady flow of a power-law fluid past a stationary circular cylinder. The governing nonlinear equations, expressed in terms of a stream function and vorticity, were solved by finite differences for Reynolds numbers (based on the radius of the cylinder)R=5,20, 40 for various power-law indices,n. Parameters such as the drag coefficient, separation angle, wake length and critical Reynolds number are presented and contrasted with those of a Newtonian fluid (n=1) to illustrate the non-Newtonian effects. For a given-Reynolds number a consistent behaviour withn was observed in the parameters for the ranges considered. The results obtained for the Newtonian case agree well with documented results.  相似文献   
8.
A new method is presented to analyze reflection losses of integrated mirrors, taking into account the exact guided mode profile and assuming that this profile remains unchanged up to the reflecting plane. The fraction of the reflected light coupled to one of the guided modes of the output waveguide is calculated, taking into account the mirror reflection coefficient. The influence of both translation and tilt of the reflecting plane is investigated. The method applies for every guided mode and any reflection angles. Numerical calculations are derived for a 90° optical corner mirror  相似文献   
9.
10.
Abstract. The influence of missing observations on the linear prediction of a stationary time series is investigated. Simple bounds for the prediction error variance and asymptotic behaviours for short and long‐memory processes respectively are presented.  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