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   8201篇
  免费   112篇
  国内免费   39篇
化学   4903篇
晶体学   76篇
力学   327篇
数学   1226篇
物理学   1820篇
  2022年   112篇
  2021年   137篇
  2020年   174篇
  2019年   183篇
  2018年   189篇
  2017年   201篇
  2016年   262篇
  2015年   123篇
  2014年   205篇
  2013年   397篇
  2012年   342篇
  2011年   388篇
  2010年   296篇
  2009年   290篇
  2008年   327篇
  2007年   320篇
  2006年   256篇
  2005年   218篇
  2004年   228篇
  2003年   201篇
  2002年   227篇
  2001年   136篇
  2000年   118篇
  1999年   80篇
  1998年   86篇
  1997年   79篇
  1995年   108篇
  1994年   115篇
  1993年   98篇
  1992年   73篇
  1991年   107篇
  1990年   98篇
  1989年   101篇
  1988年   72篇
  1987年   86篇
  1986年   75篇
  1985年   101篇
  1984年   134篇
  1983年   84篇
  1982年   103篇
  1981年   81篇
  1980年   86篇
  1979年   125篇
  1978年   120篇
  1977年   113篇
  1976年   122篇
  1975年   98篇
  1974年   70篇
  1973年   96篇
  1970年   71篇
排序方式: 共有8352条查询结果,搜索用时 15 毫秒
91.
The channeling of hydrogen atoms in bundles of carbon nanotubes in the presence of vacancies on walls and adsorbed atoms inside the tubes is studied by means of computer simulation. A change in the parameters of the beam of channeling particles during interaction with the indicated defects makes it possible to detect the structural damage of nanotube bundles.  相似文献   
92.
We review the experimental results on the P-even and P-odd angular correlations of fission fragments in the fission of the 235U and 239Pu nuclei induced by unpolarized and polarized resonance neutrons, and on the TRI and ROT effects in the ternary and binary fission of actinides induced by polarized thermal neutrons. Also reported are the measured yields of prompt and delayed neutrons per fission event. The experimental data are analyzed within a novel theoretical framework developed by the JINR—RNC KI Collaboration, whereby the reduction of the multidimensional phase space of fission fragments to the JπK-channel space is consistently validated and the role of resonance interference in the observed correlation effects is revealed.  相似文献   
93.
A new theoretical (semiempirical) model of diffusion-drift charge carrier transport in layers with a fractal structure based on a partial differential equation with a fractional time derivative has been proposed. It has been shown by numerical calculations that a decrease in the order of the fractional derivative in the presence of the external electric field leads to broadening and asymmetry of the spatial distributions of charge carriers, which physically corresponds to intensification of scattering processes.  相似文献   
94.
The purpose TUS space experiment is to study cosmic rays of ultrahigh energies produced by extensive air showers from space. The concentrator is located on satellite, made in the form of the Fresnel mirror towards the earth’s atmosphere, the focus of which is a photodetector. The angle of view of the mirror is ±4.5° that for a given height of the orbit corresponds to the area 80 × 80 km2 on ground. The ground complex consisting of a number of stations, to check the optical system of the experiment is created, (their location and the amount will be determined after the launch of the satellite based on its actual orbit).  相似文献   
95.
96.
We consider the Weyl asymptotic formula
  相似文献   
97.

Background  

Although cognitive processes such as reading and calculation are associated with reproducible cerebral networks, inter-individual variability is considerable. Understanding the origins of this variability will require the elaboration of large multimodal databases compiling behavioral, anatomical, genetic and functional neuroimaging data over hundreds of subjects. With this goal in mind, we designed a simple and fast acquisition procedure based on a 5-minute functional magnetic resonance imaging (fMRI) sequence that can be run as easily and as systematically as an anatomical scan, and is therefore used in every subject undergoing fMRI in our laboratory. This protocol captures the cerebral bases of auditory and visual perception, motor actions, reading, language comprehension and mental calculation at an individual level.  相似文献   
98.
Spatial redistribution of microparticles in a suspension on exposure to the interference laser field depending on the parameters of the particles and the field characteristics has been analyzed theoretically. Results of experimental investigations are presented that illustrate the capture of an ensemble of polymeric small spheres and also of the lymphocytes of human blood and other microparticles in a liquid in the interference radiation bands of the He–Ne laser.  相似文献   
99.
100.
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