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   1466715篇
  免费   29983篇
  国内免费   7876篇
化学   756005篇
晶体学   20651篇
力学   77020篇
综合类   110篇
数学   250757篇
物理学   400031篇
  2021年   13643篇
  2020年   16071篇
  2019年   16224篇
  2018年   14866篇
  2017年   13112篇
  2016年   29275篇
  2015年   21259篇
  2014年   30870篇
  2013年   75134篇
  2012年   45385篇
  2011年   47221篇
  2010年   40627篇
  2009年   41803篇
  2008年   44383篇
  2007年   41386篇
  2006年   44972篇
  2005年   38052篇
  2004年   37659篇
  2003年   34287篇
  2002年   34541篇
  2001年   35355篇
  2000年   29070篇
  1999年   24595篇
  1998年   21893篇
  1997年   21717篇
  1996年   21537篇
  1995年   19511篇
  1994年   18997篇
  1993年   18581篇
  1992年   19358篇
  1991年   19517篇
  1990年   18693篇
  1989年   18682篇
  1988年   18303篇
  1987年   18107篇
  1986年   17147篇
  1985年   23471篇
  1984年   24403篇
  1983年   20429篇
  1982年   22003篇
  1981年   21180篇
  1980年   20515篇
  1979年   21029篇
  1978年   22127篇
  1977年   21806篇
  1976年   21593篇
  1975年   20374篇
  1974年   20068篇
  1973年   20485篇
  1972年   14934篇
排序方式: 共有10000条查询结果,搜索用时 15 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