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   2774篇
  免费   129篇
  国内免费   18篇
化学   2257篇
晶体学   50篇
力学   23篇
数学   131篇
物理学   460篇
  2022年   14篇
  2021年   25篇
  2020年   38篇
  2019年   57篇
  2018年   30篇
  2017年   16篇
  2016年   74篇
  2015年   64篇
  2014年   77篇
  2013年   110篇
  2012年   150篇
  2011年   190篇
  2010年   108篇
  2009年   85篇
  2008年   174篇
  2007年   171篇
  2006年   177篇
  2005年   171篇
  2004年   175篇
  2003年   138篇
  2002年   106篇
  2001年   65篇
  2000年   46篇
  1999年   46篇
  1998年   44篇
  1997年   33篇
  1996年   34篇
  1995年   20篇
  1994年   15篇
  1993年   15篇
  1992年   28篇
  1991年   24篇
  1990年   21篇
  1989年   13篇
  1988年   20篇
  1987年   21篇
  1986年   15篇
  1985年   38篇
  1984年   27篇
  1983年   22篇
  1982年   23篇
  1981年   27篇
  1980年   19篇
  1979年   32篇
  1978年   12篇
  1977年   14篇
  1976年   17篇
  1975年   16篇
  1974年   13篇
  1973年   13篇
排序方式: 共有2921条查询结果,搜索用时 15 毫秒
1.
Journal of Radioanalytical and Nuclear Chemistry - Extraction chromatography flow-sheet employing octyl(phenyl)-N,N-diisobutylcarbonoylmethylphosphine oxide and bis(2-ethylhexyl) hydrogen phosphate...  相似文献   
2.
3.
Infection of hosts by morbilliviruses is facilitated by the interaction between viral hemagglutinin (H-protein) and the signaling lymphocytic activation molecule (SLAM). Recently, the functional importance of the n-terminal region of human SLAM as a measles virus receptor was demonstrated. However, the functional roles of this region in the infection process by other morbilliviruses and host range determination remain unknown, partly because this region is highly flexible, which has hampered accurate structure determination of this region by X-ray crystallography. In this study, we analyzed the interaction between the H-protein from canine distemper virus (CDV-H) and SLAMs by a computational chemistry approach. Molecular dynamics simulations and fragment molecular orbital analysis demonstrated that the unique His28 in the N-terminal region of SLAM from Macaca is a key determinant that enables the formation of a stable interaction with CDV-H, providing a basis for CDV infection in Macaca. The computational chemistry approach presented should enable the determination of molecular interactions involving regions of proteins that are difficult to predict from crystal structures because of their high flexibility.  相似文献   
4.
We study the relation between the cohomology of general linear and symmetric groups and their respective quantizations, using Schur algebras and standard homological techniques to build appropriate spectral sequences. As our methods fit inside a much more general context within the theory of finite-dimensional algebras, we develop our results first in that general setting, and then specialize to the above situations. From this we obtain new proofs of several known results in modular representation theory of symmetric groups. Moreover, we reduce certain questions about computing extensions for symmetric groups and Hecke algebras to questions about extensions for general linear groups and their quantizations.  相似文献   
5.
Let Cld AW (X) be the hyperspace of nonempty closed subsets of a normed linear space X with the Attouch–Wets topology. It is shown that the space Cld AW (X) and its various subspaces are AR's. Moreover, if X is an infinite-dimensional Banach space with weight w(X) then Cld AW (X) is homeomorphic to a Hilbert space with weight 2 w(X).  相似文献   
6.
7.
8.
A multi-layer chip inductor (MCI) was fabricated using polycrystalline Li–Zn–Cu–Mn ferrite and the green-sheet technique, and its complex impedance spectrum was evaluated with the help of numerical calculations. The complex impedance spectra of the MCI component using Ni–Zn–Cu ferrite, which have been widely used for this application, were very sensitive to the residual stress and deviated much from the calculated values; however, it was found that the complex impedance spectrum of the MCI component using Li–Zn–Cu–Mn ferrite is quite well reproduced by calculation, where the complex permittivity and permeability of the polycrystalline ferrite as well as the MCI dimensions, were used. It implied that the magneto-striction effect was negligible in case of MCI using Li–Zn–Cu–Mn ferrite, and that the difference was related to magneto-strictive coefficient of the polycrystalline ferrite. Consequently, utilization of Li–Zn–Cu–Mn ferrite enabled us to easily design the complex impedance of MCI component.  相似文献   
9.
Taking into account pseudoscalar as well as scalar condensates, we reexamine the chiral restoration path on the chiral manifold. We shall see both condensates coherently produce a density wave at a certain density, which delays chiral restoration as density or temperature is increased.  相似文献   
10.
Suffix trees are a well-known and widely-studied data structure highly useful for string matching. The suffix tree of a string w can be constructed in O(n) time and space, where n denotes the length of w. Larsson achieved an efficient algorithm to maintain suffix trees for a sliding window. It contributes to prediction by partial matching (PPM) style statistical data compression scheme. Compact directed acyclic word graphs (CDAWGs) are a more space-economical data structure for indexing strings. In this paper we propose a linear-time algorithm to maintain CDAWGs for a sliding window.  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