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   1369750篇
  免费   44094篇
  国内免费   19267篇
化学   693848篇
晶体学   20830篇
力学   78961篇
综合类   767篇
数学   248652篇
物理学   390053篇
  2022年   12847篇
  2021年   16655篇
  2020年   19015篇
  2019年   19404篇
  2018年   14085篇
  2016年   31009篇
  2015年   24516篇
  2014年   35356篇
  2013年   80617篇
  2012年   42959篇
  2011年   37713篇
  2010年   40669篇
  2009年   43317篇
  2008年   35420篇
  2007年   29687篇
  2006年   37459篇
  2005年   27919篇
  2004年   29438篇
  2003年   27965篇
  2002年   29275篇
  2001年   28044篇
  2000年   24973篇
  1999年   23627篇
  1998年   22288篇
  1997年   22193篇
  1996年   22308篇
  1995年   20260篇
  1994年   19564篇
  1993年   18855篇
  1992年   18613篇
  1991年   18855篇
  1990年   17982篇
  1989年   17890篇
  1988年   17355篇
  1987年   17376篇
  1986年   16234篇
  1985年   22580篇
  1984年   23838篇
  1983年   20002篇
  1982年   21640篇
  1981年   20849篇
  1980年   20154篇
  1979年   20291篇
  1978年   21603篇
  1977年   21204篇
  1976年   20839篇
  1975年   19503篇
  1974年   19130篇
  1973年   19561篇
  1972年   14106篇
排序方式: 共有10000条查询结果,搜索用时 16 毫秒
121.
122.
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   
123.
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   
124.
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   
125.
Photoelectrochemical (PEC) cytosensors, a combination of the PEC process and the living-cell assay, have emerged as a powerful tool in the analytical and biological science. This mini review provides a brief introduction of this arena and summaries the key steps about the development of PEC cytosensors with representative examples, followed by future prospects based on our own opinions.  相似文献   
126.
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   
127.
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   
128.
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   
129.
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   
130.
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   
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