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   1305348篇
  免费   29573篇
  国内免费   7675篇
化学   649050篇
晶体学   20090篇
力学   73968篇
综合类   102篇
数学   238483篇
物理学   360903篇
  2021年   13449篇
  2020年   15884篇
  2019年   16017篇
  2016年   27380篇
  2015年   20590篇
  2014年   30278篇
  2013年   74114篇
  2012年   35916篇
  2011年   31167篇
  2010年   35770篇
  2009年   38506篇
  2008年   31228篇
  2007年   26352篇
  2006年   33731篇
  2005年   25760篇
  2004年   27568篇
  2003年   26423篇
  2002年   27784篇
  2001年   27176篇
  2000年   23947篇
  1999年   22131篇
  1998年   20776篇
  1997年   20826篇
  1996年   20989篇
  1995年   19073篇
  1994年   18525篇
  1993年   18029篇
  1992年   18103篇
  1991年   18342篇
  1990年   17559篇
  1989年   17642篇
  1988年   17236篇
  1987年   17250篇
  1986年   16121篇
  1985年   22580篇
  1984年   23781篇
  1983年   19956篇
  1982年   21609篇
  1981年   20818篇
  1980年   20176篇
  1979年   20402篇
  1978年   21647篇
  1977年   21305篇
  1976年   20988篇
  1975年   19646篇
  1974年   19280篇
  1973年   19703篇
  1972年   14233篇
  1968年   12179篇
  1967年   12536篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
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   
112.
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   
113.
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   
114.
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   
115.
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   
116.
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   
117.
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   
118.
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   
119.
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   
120.
Journal of Radioanalytical and Nuclear Chemistry - In this paper a study for the selection of an NPE (nonylphenol ethoxylates)—free cocktail is discussed in order to be used for our routine...  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