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   1484212篇
  免费   34135篇
  国内免费   9585篇
化学   638779篇
晶体学   20007篇
力学   74250篇
综合类   192篇
数学   238376篇
物理学   358693篇
无线电   197635篇
  2021年   15244篇
  2020年   17730篇
  2019年   17912篇
  2016年   29423篇
  2015年   22090篇
  2014年   33274篇
  2013年   79262篇
  2012年   37997篇
  2011年   32427篇
  2010年   38386篇
  2009年   43825篇
  2008年   36214篇
  2007年   32411篇
  2006年   41105篇
  2005年   32029篇
  2004年   34313篇
  2003年   32931篇
  2002年   34310篇
  2001年   33392篇
  2000年   30264篇
  1999年   28507篇
  1998年   27440篇
  1997年   27364篇
  1996年   26892篇
  1995年   24766篇
  1994年   24180篇
  1993年   23504篇
  1992年   23075篇
  1991年   23259篇
  1990年   22074篇
  1989年   21689篇
  1988年   20839篇
  1987年   19645篇
  1986年   18396篇
  1985年   24918篇
  1984年   26169篇
  1983年   22147篇
  1982年   23574篇
  1981年   22767篇
  1980年   22012篇
  1979年   21869篇
  1978年   23165篇
  1977年   22727篇
  1976年   22233篇
  1975年   20891篇
  1974年   20501篇
  1973年   20970篇
  1972年   15199篇
  1968年   12939篇
  1967年   13052篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
Journal of Applied Mechanics and Technical Physics - Turbulent mixing at interfaces of three-layer gas systems after shock-wave passage has been studied. The influence of the initial roughness of...  相似文献   
162.
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   
163.
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   
164.
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   
165.
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   
166.
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   
167.
Luo  Hao  Chen  Long 《Mathematical Programming》2022,195(1-2):735-781
Mathematical Programming - Convergence analysis of accelerated first-order methods for convex optimization problems are developed from the point of view of ordinary differential equation solvers. A...  相似文献   
168.
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   
169.
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   
170.
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