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   165篇
  免费   7篇
  国内免费   2篇
化学   83篇
晶体学   2篇
力学   5篇
数学   45篇
物理学   39篇
  2023年   2篇
  2022年   1篇
  2021年   2篇
  2020年   4篇
  2018年   2篇
  2017年   5篇
  2016年   8篇
  2015年   8篇
  2014年   7篇
  2013年   11篇
  2012年   9篇
  2011年   13篇
  2010年   16篇
  2009年   9篇
  2008年   13篇
  2007年   7篇
  2006年   8篇
  2005年   8篇
  2004年   4篇
  2003年   1篇
  2002年   13篇
  2001年   4篇
  2000年   1篇
  1999年   3篇
  1998年   2篇
  1997年   1篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   1篇
  1990年   1篇
  1989年   1篇
  1984年   1篇
  1980年   1篇
  1974年   1篇
排序方式: 共有174条查询结果,搜索用时 109 毫秒
71.
We consider the problem of infrared divergencies in String theory in Embeddings Manifolds by means of the Nash Theorem of Riemann metrics parametrized by immersions.  相似文献   
72.
73.
To evaluate the potential aroma of Aragonez clonal red musts, several free and glycosidically bound odourant compounds were extracted. Then, the gas chromatography-olfactometry (GC-O) posterior intensity method was used to evaluate their odour intensity and the compounds were identified by gas chromatography-mass spectrometry (GC-MS). A group of eight sniffers evaluated free and bound fractions of Aragonez musts and perceived forty-three and twenty-two odourant peaks respectively. Furaneol (burnt sugar, candy-cotton) and vanillin (vanilla, sweet) were identified in both free and bound fractions of Aragonez musts, indicating their grape-derived origin. Principal component analysis (PCA) was applied to the posterior intensity method data and a relationship between the different odourant compound variables and the free fractions was established. Two principal components (PCs) were found which together explained 100% of the total variance. A large number of potentially important but yet unknown odourants was detected by the GC-O analysis.  相似文献   
74.
We consider the elementary operator L, acting on the Hilbert-Schmidt Class C2(H), given by L(T)=ATB, with A and B bounded operators on H. We establish necessary and sufficient conditions on A and B for L to be a 2-isometry or a 3-isometry. We derive sufficient conditions for L to be an n-isometry. We also give several illustrative examples involving the weighted shift operator on l2 and the multiplication operator on the Dirichlet space.  相似文献   
75.
We write a space-time Feynman Path Integral representation for scattered elastic wave fields from a weakly anisotropic non-homogeneity.  相似文献   
76.
We characterize projections on spaces of Lipschitz functions expressed as the average of two and three linear surjective isometries. Generalized bi-circular projections are the only projections on these spaces given as the convex combination of two surjective isometries.  相似文献   
77.
78.
If X is a Banach space with a normalized unconditional Schauder basis (xn), we define whenever and obtain estimates for μX,(xn) when every continuous m-homogeneous polynomial from X into Y is absolutely (q,1) summing. Our results provide new information on coincidence situations between the space of absolutely summing m-homogeneous polynomials and the whole space of continuous m-homogeneous polynomials. In particular, when m=1, we obtain new contributions to the linear theory of absolutely summing operators.  相似文献   
79.
80.
We establish conditions under which Oja–Adams' learning models are gradient, semi-gradient, or gradient-like systems. We consider both single and multi-output models. The multi-output learning models are represented by matrix differential equations whose analysis require techniques from matrix calculus. We also derive the stability behavior of these systems while restricted to naturally defined invariant sets.  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