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   1351篇
  免费   40篇
  国内免费   9篇
化学   970篇
晶体学   10篇
力学   28篇
数学   202篇
物理学   190篇
  2023年   16篇
  2022年   25篇
  2021年   48篇
  2020年   27篇
  2019年   41篇
  2018年   32篇
  2017年   35篇
  2016年   55篇
  2015年   41篇
  2014年   41篇
  2013年   86篇
  2012年   79篇
  2011年   90篇
  2010年   49篇
  2009年   50篇
  2008年   98篇
  2007年   91篇
  2006年   86篇
  2005年   67篇
  2004年   59篇
  2003年   27篇
  2002年   32篇
  2001年   14篇
  2000年   19篇
  1999年   8篇
  1998年   15篇
  1997年   14篇
  1996年   13篇
  1995年   10篇
  1994年   12篇
  1993年   15篇
  1992年   8篇
  1991年   8篇
  1990年   7篇
  1989年   7篇
  1988年   11篇
  1987年   7篇
  1985年   4篇
  1984年   10篇
  1983年   6篇
  1982年   4篇
  1980年   3篇
  1978年   2篇
  1977年   2篇
  1976年   2篇
  1924年   2篇
  1912年   2篇
  1911年   2篇
  1910年   2篇
  1858年   1篇
排序方式: 共有1400条查询结果,搜索用时 31 毫秒
121.
An invariant definition of mass is given, within the context of a geometric unified theory, in terms of the geometric connection and the matter current. This geometric mass corresponds to the concept of self energy and leads to the mass parameter in Dirac's equation.  相似文献   
122.
We find the conjugacy vector, i.e., we determine the number of conjugacy classes which compose the sets of the elements with centralizers of equal order, for several general families ofp-groups of maximal class which include those of order up top 9. As a consequence, we obtain the number of conjugacy classes,r(G), for the groups in these families. Also, we provide upper and lower bounds forr(G) and characterize when they are attained. Examples are given showing that the bounds are actually attained. This work has been supported by DGICYT grant PB91-0446 and by the University of the Basque Country.  相似文献   
123.
The object of this paper is to provide a systematic treatment of bargaining procedures as a basis for negotiation. An innovative fuzzy logic approach to analyze n-person cooperative games is developed. A couple of indices, the Good Deal Index and the Counterpart Convenience Index are proposed to characterize the heuristic of bargaining and to provide a solution concept. The indices are examined theoretically and experimentally by analyzing three case studies. The results verify the validity of the approach.  相似文献   
124.
125.
126.
Aluminum Chloride Phthalocyanine (AlPcCl) can be used as a photosensitizer (PS) for Photodynamic Inactivation of Microorganisms (PDI). The AlPcCl showed favorable characteristics for PDI due to high quantum yield of singlet oxygen (ΦΔ) and photostability. Physicochemical properties and photodynamic inactivation of AlPcCl incorporated in polymeric micelles of tri‐block copolymer (P‐123 and F‐127) against microorganisms Staphylococcus aureus, Escherichia coli and Candida albicans were investigated in this work. Previously, it was observed that the AlPcCl undergoes self‐aggregation in F‐127, while in P‐123 the PS is in a monomeric form suitable for PDI. Due to the self‐aggregation of AlPcCl in F‐127, this formulation did not show any effect on these microorganisms. On the other hand, AlPcCl formulated in P‐123 was effective against S. aureus and C. albicans and the death of microorganisms was dependent on the PS concentration and illumination time. Additionally, it was found that the values of PS concentration and illumination time to eradicate 90% of the initial population of microorganisms (IC90 and D90, respectively) were small for the AlPcCl in P‐123, showing the effectiveness of this formulation for PDI.  相似文献   
127.
128.
129.
The goal of this paper is to introduce a class of \(C^\infty \) functions derivatives of which satisfy quantitative size estimates. The estimates, called global \(L^q\) Gevrey estimates, first arose in the work of Boggess and Raich ( J. Fourier Anal. Appl. 19:180–224, 2013) when they investigated how to capture a particular type of exponential decay through estimates on the Fourier transform. In the present work, we refine the notion of global \(L^q\)-Gevrey functions and include a discussion of the function theory as well as the relationship to Gevrey classes and known function spaces. In addition, we present explicit examples of global \(L^q\)-Gevrey functions and ways to generate new global \(L^q\)-Gevrey functions from old ones. We conclude with three applications: The first is solving a Carleman-type problem for constructing functions derivatives of which are a given sequence of global \(L^q\)-Gevrey functions. The other two applications concern extensions of a given global \(L^q\)-Gevrey function: the first is constructing an almost analytic extension, and the second is building an approximate solution to a first-order complex vector field coefficients of which are global \(L^q\)-Gevrey functions.  相似文献   
130.
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