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   427494篇
  免费   5147篇
  国内免费   2084篇
化学   223917篇
晶体学   5579篇
力学   19292篇
综合类   61篇
数学   50679篇
物理学   135197篇
  2020年   3432篇
  2019年   3814篇
  2018年   5708篇
  2017年   5788篇
  2016年   7567篇
  2015年   4875篇
  2014年   7382篇
  2013年   18310篇
  2012年   14948篇
  2011年   17948篇
  2010年   12612篇
  2009年   12512篇
  2008年   16222篇
  2007年   16329篇
  2006年   15376篇
  2005年   16249篇
  2004年   14913篇
  2003年   12348篇
  2002年   11082篇
  2001年   12336篇
  2000年   9460篇
  1999年   7176篇
  1998年   6070篇
  1997年   5955篇
  1996年   5839篇
  1995年   5220篇
  1994年   5234篇
  1993年   5185篇
  1992年   5543篇
  1991年   5531篇
  1990年   5160篇
  1989年   5050篇
  1988年   5031篇
  1987年   4905篇
  1986年   4722篇
  1985年   6433篇
  1984年   6643篇
  1983年   5493篇
  1982年   5835篇
  1981年   5624篇
  1980年   5269篇
  1979年   5615篇
  1978年   5881篇
  1977年   5833篇
  1976年   5883篇
  1975年   5378篇
  1974年   5552篇
  1973年   5617篇
  1972年   4149篇
  1971年   3374篇
排序方式: 共有10000条查询结果,搜索用时 127 毫秒
31.
Radiophysics and Quantum Electronics - A well-known simplified model of turbulent convection from local sources of buoyancy and/or momentum acting for a short time has been developed and...  相似文献   
32.
33.
34.
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   
35.
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   
36.
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   
37.
A temperature control unit was implemented to vary the temperature of samples studied on a commercial Mobile Universal Surface Explorer nuclear magnetic resonance (MOUSE-NMR) apparatus. The device was miniaturized to fit the maximum MOUSE sampling depth (25 mm). It was constituted by a sample holder sandwiched between two heat exchangers placed below and above the sample. Air was chosen as the fluid to control the temperature at the bottom of the sample, at the interface between the NMR probe and the sample holder, in order to gain space. The upper surface of the sample was regulated by the circulation of water inside a second heat exchanger placed above the sample holder. The feasibility of using such a device was demonstrated first on pure water and then on several samples of bread dough with different water contents. For this, T1 relaxation times were measured at various temperatures and depths and were then compared with those acquired with a conventional compact closed-magnet spectrometer. Discussion of results was based on biochemical transformations in bread dough (starch gelatinization and gluten heat denaturation). It was demonstrated that, within a certain water level range, and because of the low magnetic field strength of the MOUSE, a linear relationship could be established between T1 relaxation times and the local temperature in the dough sample.  相似文献   
38.
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   
39.
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   
40.
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