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   658445篇
  免费   7134篇
  国内免费   2503篇
化学   340068篇
晶体学   8022篇
力学   32075篇
综合类   78篇
数学   86979篇
物理学   200860篇
  2021年   5805篇
  2020年   6463篇
  2019年   7180篇
  2018年   9572篇
  2017年   9701篇
  2016年   13562篇
  2015年   7689篇
  2014年   12455篇
  2013年   29134篇
  2012年   23070篇
  2011年   27663篇
  2010年   20425篇
  2009年   20166篇
  2008年   26081篇
  2007年   25936篇
  2006年   23836篇
  2005年   21405篇
  2004年   19634篇
  2003年   17557篇
  2002年   17466篇
  2001年   18585篇
  2000年   14377篇
  1999年   11037篇
  1998年   9487篇
  1997年   9328篇
  1996年   8831篇
  1995年   7928篇
  1994年   7996篇
  1993年   7481篇
  1992年   8015篇
  1991年   8457篇
  1990年   8000篇
  1989年   7864篇
  1988年   7678篇
  1987年   7410篇
  1986年   7160篇
  1985年   9364篇
  1984年   9736篇
  1983年   8174篇
  1982年   8584篇
  1981年   7996篇
  1980年   7575篇
  1979年   8135篇
  1978年   8526篇
  1977年   8463篇
  1976年   8443篇
  1975年   8002篇
  1974年   7907篇
  1973年   8255篇
  1972年   6109篇
排序方式: 共有10000条查询结果,搜索用时 125 毫秒
81.
Nonlinear Dynamics - In this paper, we analyze the effect which the choice of a friction model has on tippe top inversion in the case where the resulting action of all dissipative forces is...  相似文献   
82.
Optical and Quantum Electronics - Classification of hyperspectral image (HSI) is widely used for the study of remotely sensed images. Convolutional Neural Networks (CNNs) are one of the most...  相似文献   
83.
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   
84.
Radiophysics and Quantum Electronics - We find self-consistent stationary distributions of the electric field and plasma density in the process of ionization self-channeling of quasielectrostatic...  相似文献   
85.
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   
86.
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   
87.
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   
88.
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   
89.
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   
90.
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   
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