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   1572821篇
  免费   32294篇
  国内免费   8312篇
化学   694369篇
晶体学   20475篇
力学   75674篇
综合类   106篇
数学   244315篇
物理学   380519篇
无线电   197969篇
  2021年   14817篇
  2020年   17441篇
  2019年   17581篇
  2018年   15152篇
  2016年   30549篇
  2015年   22004篇
  2014年   32924篇
  2013年   78852篇
  2012年   42636篇
  2011年   41694篇
  2010年   41471篇
  2009年   45902篇
  2008年   44075篇
  2007年   41650篇
  2006年   46607篇
  2005年   39482篇
  2004年   40067篇
  2003年   37259篇
  2002年   37851篇
  2001年   37840篇
  2000年   32969篇
  1999年   29625篇
  1998年   27707篇
  1997年   27475篇
  1996年   27018篇
  1995年   24783篇
  1994年   24277篇
  1993年   23690篇
  1992年   23726篇
  1991年   23843篇
  1990年   22650篇
  1989年   22261篇
  1988年   21460篇
  1987年   20159篇
  1986年   18997篇
  1985年   25467篇
  1984年   26499篇
  1983年   22377篇
  1982年   23748篇
  1981年   22941篇
  1980年   22185篇
  1979年   22202篇
  1978年   23371篇
  1977年   22952篇
  1976年   22554篇
  1975年   21238篇
  1974年   20869篇
  1973年   21326篇
  1972年   15527篇
  1967年   13327篇
排序方式: 共有10000条查询结果,搜索用时 78 毫秒
191.
Ukrainian Mathematical Journal - We establish new criteria of compatibility for a linear system of equations (equivalent to the Kronecker–Capelli theorem) or inequalities (equivalent to the...  相似文献   
192.
Chen  R. J.  Chen  W.  Kong  F. L. 《Analysis Mathematica》2022,48(1):19-28

Restricted testing conditions were considered recently. For the maximal operator, Hytönen, Li and Sawyer [8] first obtained parental testing condition. Later, they [9] showed that it suffices to restrict testing to doubling cubes. Chen and Lacey [3] gave a similar restricted testing condition. In our paper, we discuss a version of the latter in the multilinear setting.

  相似文献   
193.
Kirovskaya  I. A.  Filatova  T. N.  Nor  P. E. 《Semiconductors》2021,55(2):228-233
Semiconductors - According to developed methods, in the fields of the mutual solubility of initial binary compounds (InP, InSb, and CdS), solid solutions of the InP–CdS and InSb–CdS...  相似文献   
194.
Journal of Fourier Analysis and Applications - We develop a theory of Sobolev orthogonal polynomials on the Sierpiński gasket ( $$SG$$ ), which is a fractal set that can be viewed as a limit...  相似文献   
195.
Melnikov  A.  Aksentyev  A.  Senichev  Y. 《Physics of Atomic Nuclei》2021,84(11):1871-1873
Physics of Atomic Nuclei - We have investigated the robustness of the spin-navigator based method for manipulating the beam polarization to bend magnet installation errors. Toward that end,...  相似文献   
196.
Physics of the Solid State - The external factors which influence the ferromagnetic resonance (FMR) line width in bilayer (ferromagnet/antiferromagnet) exchange-biased systems are studied. The...  相似文献   
197.
Antimony triselenide (Sb2Se3) nanoflake-based nitrogen dioxide (NO2) sensors exhibit a progressive bifunctional gas-sensing performance, with a rapid alarm for hazardous highly concentrated gases, and an advanced memory-type function for low-concentration (<1 ppm) monitoring repeated under potentially fatal exposure. Rectangular and cuboid shaped Sb2Se3 nanoflakes, comprising van der Waals planes with large surface areas and covalent bond planes with small areas, can rapidly detect a wide range of NO2 gas concentrations from 0.1 to 100 ppm. These Sb2Se3 nanoflakes are found to be suitable for physisorption-based gas sensing owing to their anisotropic quasi-2D crystal structure with extremely enlarged van der Waals planes, where they are humidity-insensitive and consequently exhibit an extremely stable baseline current. The Sb2Se3 nanoflake sensor exhibits a room-temperature/low-voltage operation, which is noticeable owing to its low energy consumption and rapid response even under a NO2 gas flow of only 1 ppm. As a result, the Sb2Se3 nanoflake sensor is suitable for the development of a rapid alarm system. Furthermore, the persistent gas-sensing conductivity of the sensor with a slow decaying current can enable the development of a progressive memory-type sensor that retains the previous signal under irregular gas injection at low concentrations.  相似文献   
198.
Crystallography Reports - The orientation of grains and the special boundaries formed by them in multicrystalline silicon has been studied by electron backscattered diffraction. It is found that...  相似文献   
199.
Crystallography Reports - Some questions related to the establishment, development, and prospects of physical studies using inelastic thermal-neutron scattering are briefly reviewed. The directions...  相似文献   
200.
Theoretical and Mathematical Physics - The fractional derivative method is used to take wave dispersion into account in the wave equation when describing the propagation of gravitational soliton...  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