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   1219篇
  免费   46篇
  国内免费   5篇
化学   969篇
晶体学   10篇
力学   6篇
数学   66篇
物理学   219篇
  2023年   10篇
  2022年   11篇
  2021年   15篇
  2020年   15篇
  2019年   24篇
  2018年   15篇
  2017年   19篇
  2016年   26篇
  2015年   25篇
  2014年   33篇
  2013年   78篇
  2012年   63篇
  2011年   97篇
  2010年   43篇
  2009年   37篇
  2008年   86篇
  2007年   76篇
  2006年   72篇
  2005年   76篇
  2004年   77篇
  2003年   69篇
  2002年   74篇
  2001年   13篇
  2000年   17篇
  1999年   13篇
  1998年   14篇
  1997年   11篇
  1996年   15篇
  1995年   6篇
  1994年   4篇
  1993年   5篇
  1991年   7篇
  1990年   6篇
  1989年   4篇
  1988年   6篇
  1986年   3篇
  1985年   12篇
  1984年   12篇
  1982年   6篇
  1981年   13篇
  1980年   10篇
  1979年   7篇
  1978年   4篇
  1977年   8篇
  1976年   4篇
  1975年   3篇
  1974年   3篇
  1973年   3篇
  1964年   3篇
  1961年   2篇
排序方式: 共有1270条查询结果,搜索用时 0 毫秒
11.
12.
In this work, the application of an undecimated wavelet transformation together with digital interferometric contrast to improve the resulting reconstructions in a digital hard X‐ray Gabor holographic microscope is shown. Specifically, the starlet transform is used together with digital Zernike contrast. With this contrast, the results show that only a small set of scales from the hologram are, in effect, useful, and it is possible to enhance the details of the reconstruction.  相似文献   
13.
A series of solvable lattice models with face interaction are introduced on the basis of the affine Lie algebraX n (1) =A n (1) ,B n (1) ,C n (1) ,D n (1) . The local states taken on by the fluctuation variables are the dominant integral weights ofX n (1) of a fixed level. Adjacent local states are subject to a condition related to the vector representation ofX n . The Boltzmann weights are parametrized by elliptic theta functions and solve the star-triangle relation.  相似文献   
14.
A model is considered in which the bonds of a lattice are covered by rodlike molecules. Neighboring molecular ends interact with orientation-dependent interactions. The model exhibits closed -loop phase diagrams and double critical points. Exact coexistence surfaces are calculated for the model on the Bethe, honeycomb, and square lattices. The nature of the doubling of the critical exponent near a double critical point is calculated. The behavior of the critical line in the neighborhood of a double critical point is calculated exactly.  相似文献   
15.
We introduce certain families of elliptic functions involving the Weierstrass ℘-function via q-series systematically and investigate their analytic and algebraic properties. Especially, we give examples of non-linear algebraic ordinary differential equations satisfied by some such elliptic functions. 2000 Mathematics Subject Classification: Primary–11M36, 33E05  相似文献   
16.
We investigate the adiabatic and dynamical natures of the lattice relaxation of excitons in strongly coupled electron-phonon (e-ph) systems using the extended Peierls-Hubbard model, so as to clarify the possible mechanisms of the photoinduced structural phase transition (PISPT) via multi-photon. Focusing on the growth process of relaxed domains that is induced by multi-photoexcitation, we calculate the adiabatic potential energy surfaces relevant to the nonlinear lattice relaxations of excitons in this process. Calculated potentials lead to an essential model of a multi-stepwise potential-crossing (MSPC) system that is composed of many displaced harmonic oscillators as an elementary process of the domain growth in the strongly coupled e-ph systems. We also investigate the dynamical natures in such MSPC systems calculating the time-developments the excited wave packet in this system using the density operator. It is concluded from calculated results that the system possibly develops from the lowest-energy potential state to the higher ones by the effect of the photoexcitations followed by the lattice relaxations.  相似文献   
17.
We introduce a Selberg type zeta function of two variables which interpolates several higher Selberg zeta functions. The analytic continuation, the functional equation and the determinant expression of this function via the Laplacian on a Riemann surface are obtained.Mathematics Subject Classifications (2000). Primary 11M36, Secondary 33B15  相似文献   
18.
19.
The present study was designed to show the applicability of scanning ion conductance microscopy (SICM) for imaging different types of biological samples. For this purpose, we first applied SICM to image collagen fibrils and showed the usefulness of the approach-retract scanning (ARS)/hopping mode for such samples with steep slopes. Comparison of SICM images with those obtained by AFM revealed that the ARS/hopping SICM mode can probe the surface topography of collagen fibrils and chromosomes at nanoscale resolution under liquid conditions. In addition, we successfully imaged cultured HeLa cells, with 15 μm in height by ARS/hopping SICM mode. Because SICM can obtain non-contact (or force-free) images, delicate cellular projections were visualized on the surface of the fixed cell. SICM imaging of live HeLa cells further demonstrated its applicability to study the morphological dynamics associated with biological processes on the time scale of minutes under liquid conditions. We further applied SICM for imaging the luminal surface of the trachea and succeeded in visualizing the surface of both ciliated and non-ciliated cells. These SICM images were comparable with those obtained by scanning electron microscopy. Although the dynamic mode of AFM provides better resolution than the ARS/hopping mode of SICM in some samples, only the latter can obtain contact-free images of samples with steep slopes, rendering it an important tool for observing live cells as well as unfixed or fixed soft samples with complicated shapes. Taken together, we demonstrate that SICM imaging, especially using an ARS/hopping mode, is a useful technique with unique capabilities for imaging the three-dimensional topography of a range of biological samples under physiologically relevant aqueous conditions.  相似文献   
20.
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