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   129篇
  免费   1篇
化学   41篇
力学   1篇
数学   64篇
物理学   24篇
  2023年   1篇
  2022年   1篇
  2021年   5篇
  2020年   5篇
  2019年   3篇
  2018年   5篇
  2017年   7篇
  2016年   3篇
  2015年   2篇
  2014年   3篇
  2013年   3篇
  2012年   7篇
  2011年   6篇
  2010年   5篇
  2009年   5篇
  2008年   2篇
  2007年   11篇
  2006年   7篇
  2005年   3篇
  2004年   5篇
  2003年   5篇
  2002年   3篇
  2001年   4篇
  2000年   2篇
  1999年   3篇
  1998年   2篇
  1997年   3篇
  1996年   5篇
  1995年   2篇
  1993年   2篇
  1992年   1篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1980年   1篇
  1979年   1篇
  1972年   1篇
排序方式: 共有130条查询结果,搜索用时 15 毫秒
1.
We consider a sequence of curved rods which consist of isotropic material and which are clamped on the lower base or on both bases. We study the asymptotic behaviour of the stress tensor and displacement under the assumptions of linearized elasticity when the cross‐sectional diameter of the rods tends to zero and the body force is given in the particular form. The analysis covers the case of a non‐smooth limit line of centroids. We show how the body force and the choice of the approximating curved rods can affect the strong convergence and the limit form of the stress tensor for the curved rods clamped on both bases. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
2.
3.
Automated structure verification using 1H NMR data or a combination of 1H and heteronuclear single‐quantum correlation (HSQC) data is gaining more interest as a routine application for qualitative evaluation of large compound libraries produced by synthetic chemistry. The goal of this automated software method is to identify a manageable subset of compounds and data that require human review. In practice, the automated method will flag structure and data combinations that exhibit some inconsistency (i.e. strange chemical shifts, conflicts in multiplicity, or overestimated and underestimated integration values) and validate those that appear consistent. One drawback of this approach is that no automated system can guarantee that all passing structures are indeed correct structures. The major reason for this is that approaches using only 1H or even 1H and HSQC spectra often do not provide sufficient information to properly distinguish between similar structures. Therefore, current implementations of automated structure verification systems allow, in principle, false positive results. Presented in this work is a method that greatly reduces the probability of an automated validation system passing incorrect structures (i.e. false positives). This novel method was applied to automatically validate 127 non‐proprietary compounds from several commercial sources. Presented also is the impact of this approach on false positive and false negative results. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   
4.
In present research, we investigate dynamic coupled thermoelasticity problem for a “coating-substrate” system. We present a number of models of thermoelastic deformation of the “coating-substrate” system with thermomechanical characteristics which may vary both continuously and discontinuously. To solve these problems, we use the variational principle of coupled thermoelasticity in the Laplace transforms space and hypotheses on a distribution of temperature and displacements transforms. The transforms inversion is realized according to the Durbin method. The calculations were carried out based on both proposed simplified models and FEM.  相似文献   
5.
6.
Chemistry of Natural Compounds - The aerial part of Lespedeza tomentosa (Thunb.) Maxim. growing in southern Primorsky Krai, Russian Federation, yielded 10 identified flavonoid glycosides, eight of...  相似文献   
7.
The nanotechnology development is accompanied by an intensive growth of information flow which is specially noticeable as applied to journal information flow. Now over the world there are the 69 nano-titled journals with the impact factor and/or a settled periodicity as well as the 70 those which lack stability periodicity and are in an organization stage. Only 49 nano-titled have the impact factor with the comparatively high mean value of about 3.44. The domestic nano-titled journals published in Russia, India, China, and other countries are also considered. The attention is taken that in the 2006–2010 period the 95 new nano-titled journals were organized and in 2011 this process is continuing and seems to be the most impressive. Many nano-related journals (including classical physical, chemical and materials science ones) are also described and discussed.  相似文献   
8.
Summary  Common non-parametric estimators of a probability density function (PDF) show bad performance for heavy-tailed PDFs. Using a parametric approximation of the true cumulative distribution function (CDF), the transformation-retransformation of the data is explored here as a useful tool for the reliable PDF prediction. The PDF estimators are compared by their capacity to solve a classification problem. Simulation results and an application to Web data analysis are presented, too.  相似文献   
9.
A Structural Property Concerning Abstract Commensurability of Subgroups   总被引:1,自引:0,他引:1  
Further properties of a group introduced by the first authorin 1980 (sometimes called the first Grigorchuk group) are established.These are notably that any two infinite finitely generated subgroupsof have isomorphic subgroups of finite index and that the generalizedword problem for is soluble.  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