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   1329807篇
  免费   29641篇
  国内免费   7709篇
化学   664866篇
晶体学   20200篇
力学   74343篇
综合类   101篇
数学   240726篇
物理学   366921篇
  2021年   13483篇
  2020年   15914篇
  2019年   16044篇
  2016年   27539篇
  2015年   20657篇
  2014年   30376篇
  2013年   74297篇
  2012年   37374篇
  2011年   33616篇
  2010年   36386篇
  2009年   38819篇
  2008年   33209篇
  2007年   28572篇
  2006年   35665篇
  2005年   27424篇
  2004年   29080篇
  2003年   27726篇
  2002年   28949篇
  2001年   28048篇
  2000年   24548篇
  1999年   22425篇
  1998年   20952篇
  1997年   21016篇
  1996年   21092篇
  1995年   19189篇
  1994年   18622篇
  1993年   18167篇
  1992年   18074篇
  1991年   18397篇
  1990年   17604篇
  1989年   17700篇
  1988年   17243篇
  1987年   17226篇
  1986年   16150篇
  1985年   22580篇
  1984年   23827篇
  1983年   19991篇
  1982年   21683篇
  1981年   20904篇
  1980年   20267篇
  1979年   20452篇
  1978年   21746篇
  1977年   21347篇
  1976年   21121篇
  1975年   19760篇
  1974年   19498篇
  1973年   19967篇
  1972年   14430篇
  1968年   12285篇
  1967年   12625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