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   1384篇
  免费   106篇
  国内免费   10篇
化学   895篇
晶体学   29篇
力学   60篇
数学   108篇
物理学   408篇
  2024年   8篇
  2023年   18篇
  2022年   92篇
  2021年   91篇
  2020年   62篇
  2019年   56篇
  2018年   60篇
  2017年   47篇
  2016年   70篇
  2015年   58篇
  2014年   65篇
  2013年   104篇
  2012年   100篇
  2011年   103篇
  2010年   73篇
  2009年   45篇
  2008年   48篇
  2007年   49篇
  2006年   40篇
  2005年   37篇
  2004年   33篇
  2003年   20篇
  2002年   15篇
  2001年   10篇
  2000年   8篇
  1999年   6篇
  1998年   6篇
  1997年   7篇
  1996年   13篇
  1995年   5篇
  1994年   12篇
  1993年   8篇
  1992年   7篇
  1991年   13篇
  1990年   9篇
  1989年   4篇
  1988年   8篇
  1987年   12篇
  1986年   12篇
  1985年   12篇
  1984年   5篇
  1983年   3篇
  1982年   9篇
  1981年   3篇
  1980年   5篇
  1978年   5篇
  1977年   5篇
  1976年   3篇
  1974年   4篇
  1973年   4篇
排序方式: 共有1500条查询结果,搜索用时 15 毫秒
41.
42.
Theoretical and Mathematical Physics - We explore conformal Ricci collineations (CRCs) for static space–times with maximal symmetric transverse spaces. Solving the CRC equations in the...  相似文献   
43.
Plasma Chemistry and Plasma Processing - We report plasma based fabrication of an optoelectronic device with plasmon enhanced infrared sensitivity realized by integrating plasmonic gold...  相似文献   
44.
Extraction of relevant lip features is of continuing interest in the visual speech domain. Using end-to-end feature extraction can produce good results, but at the cost of the results being difficult for humans to comprehend and relate to. We present a new, lightweight feature extraction approach, motivated by human-centric glimpse-based psychological research into facial barcodes, and demonstrate that these simple, easy to extract 3D geometric features (produced using Gabor-based image patches), can successfully be used for speech recognition with LSTM-based machine learning. This approach can successfully extract low dimensionality lip parameters with a minimum of processing. One key difference between using these Gabor-based features and using other features such as traditional DCT, or the current fashion for CNN features is that these are human-centric features that can be visualised and analysed by humans. This means that it is easier to explain and visualise the results. They can also be used for reliable speech recognition, as demonstrated using the Grid corpus. Results for overlapping speakers using our lightweight system gave a recognition rate of over 82%, which compares well to less explainable features in the literature.  相似文献   
45.
In this article, we prove some strong and weak convergence theorems for quasi-nonexpansive multivalued mappings in Banach spaces. The iterative process used is independent of Ishikawa iterative process and converges faster. Some examples are provided to validate our results. Our results extend and unify some results in the contemporary literature.  相似文献   
46.
This communication reports the successful adsorption of a water-soluble cationic fluorescent dye Acridine Orange (AO) onto Langmuir–Blodgett (LB) films of a cationic amphiphile octadecylamine (ODA) in the presence of nano-clay platelets hectorite. Acridine orange (AO) has been widely used as a stainer for the characterization of biopolymers. But AO has a tendency to form non-florescent H-dimer even in the aqueous solution. Anionic nano-clay platelets hectorite played an important role in controlling the H-dimer formation of AO in the hybrid film. Effects of various parameters in the adsorption process were investigated in detail.  相似文献   
47.
48.
49.
50.
Abstract

A novel polymeric complex has been synthesized by refluxing disodium acetylene dicarboxylate with tributyltin chloride in dry methanol. The solid-state structure of the complex has been determined by single-crystal X-ray analysis. The tin(IV) metal exhibits distorted trigonal bipyramidal geometry. Each carboxylate group of the ligand acts in a bidentate fashion, linking adjacent metal atoms to produce polymeric chains, which are cross-linked into a three-dimensional network.  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