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   1454008篇
  免费   29999篇
  国内免费   7843篇
化学   745205篇
晶体学   20793篇
力学   76881篇
综合类   112篇
数学   250037篇
物理学   398822篇
  2021年   13684篇
  2020年   16097篇
  2019年   16250篇
  2018年   15536篇
  2017年   13930篇
  2016年   29424篇
  2015年   21281篇
  2014年   30828篇
  2013年   75023篇
  2012年   44231篇
  2011年   45826篇
  2010年   40674篇
  2009年   42031篇
  2008年   43246篇
  2007年   40029篇
  2006年   42992篇
  2005年   36556篇
  2004年   36087篇
  2003年   33175篇
  2002年   33406篇
  2001年   34419篇
  2000年   28487篇
  1999年   24308篇
  1998年   21736篇
  1997年   21576篇
  1996年   21514篇
  1995年   19520篇
  1994年   19022篇
  1993年   18592篇
  1992年   19323篇
  1991年   19481篇
  1990年   18694篇
  1989年   18685篇
  1988年   18322篇
  1987年   18177篇
  1986年   17143篇
  1985年   23480篇
  1984年   24447篇
  1983年   20431篇
  1982年   21966篇
  1981年   21166篇
  1980年   20521篇
  1979年   21075篇
  1978年   22120篇
  1977年   21840篇
  1976年   21600篇
  1975年   20314篇
  1974年   20020篇
  1973年   20421篇
  1972年   14868篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
111.
112.
Statistical Inference for Stochastic Processes - The problem of linear interpolation in the context of a multivariate time series having multiple (possibly non-consecutive) missing values is...  相似文献   
113.
Siberian Mathematical Journal - A lattice homomorphism between quasi-Banach lattices is known to be compact if and only if it is a sum of a series of rank one lattice...  相似文献   
114.
Theoretical and Mathematical Physics - This paper is devoted to tetrahedron maps, which are set-theoretical solutions of the Zamolodchikov tetrahedron equation. We construct a family of tetrahedron...  相似文献   
115.
CRANAD-2 is a fluorogenic curcumin derivative used for near-infrared detection and imaging in vivo of amyloid aggregates, which are involved in neurodegenerative diseases. We explore the performance of CRANAD-2 in two super-resolution imaging techniques, namely stimulated emission depletion (STED) and single-molecule localization microscopy (SMLM), with markedly different fluorophore requirements. By conveniently adapting the concentration of CRANAD-2, which transiently binds to amyloid fibrils, we show that it performs well in both techniques, achieving a resolution in the range of 45–55 nm. Correlation of SMLM with atomic force microscopy (AFM) validates the resolution of fine features in the reconstructed super-resolved image. The good performance and versatility of CRANAD-2 provides a powerful tool for near-infrared nanoscopic imaging of amyloids in vitro and in vivo.  相似文献   
116.
Designs, Codes and Cryptography - Given an integer $$k\ge 3$$ and a group G of odd order,  if there exists a 2-(v, k, 1)-design and if v is sufficiently large then there...  相似文献   
117.
Journal of Analytical Chemistry - Silver nanoparticles modified with Eu3+ ions increase the intensity of the fluorescence signal by a factor of 125 in an analytical system containing doxycycline as...  相似文献   
118.
Computational Optimization and Applications - We consider a continuous-time optimization method based on a dynamical system, where a massive particle starting at rest moves in the conservative...  相似文献   
119.
Herein, we report a Mott-Schottky catalyst by entrapping cobalt nanoparticles inside the N-doped graphene shell (Co@NC). The Co@NC delivered excellent oxygen evolution activity with an overpotential of merely 248 mV at a current density of 10 mA cm–2 with promising long-term stability. The importance of Co encapsulated in NC has further been demonstrated by synthesizing Co nanoparticles without NC shell. The synergy between the hexagonal close-packed (hcp) and face-centered cubic (fcc) Co plays a major role to improve the OER activity, whereas the NC shell optimizes the electronic structure, improves the electron conductivity, and offers a large number of active sites in Co@NC. The density functional theory calculations have revealed that the hcp Co has a dominant role in the surface reaction of electrocatalytic oxygen evolution, whereas the fcc phase induces the built-in electric field at the interfaces with N-doped graphene to accelerate the H+ ion transport.  相似文献   
120.
Crystallography Reports - Two LiInSe2 single crystals, grown under different conditions, have been studied. Characteristics of these crystals for neutron detection have been compared using...  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