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   225920篇
  免费   3069篇
  国内免费   1317篇
化学   125566篇
晶体学   3257篇
力学   9002篇
综合类   61篇
数学   25688篇
物理学   66732篇
  2020年   1793篇
  2019年   1936篇
  2018年   2608篇
  2017年   2649篇
  2016年   3836篇
  2015年   2552篇
  2014年   3726篇
  2013年   9323篇
  2012年   7949篇
  2011年   9759篇
  2010年   6850篇
  2009年   6627篇
  2008年   9106篇
  2007年   9208篇
  2006年   8659篇
  2005年   7912篇
  2004年   7053篇
  2003年   6182篇
  2002年   6109篇
  2001年   6786篇
  2000年   5134篇
  1999年   3722篇
  1998年   3082篇
  1997年   3051篇
  1996年   3054篇
  1995年   2661篇
  1994年   2744篇
  1993年   2620篇
  1992年   2880篇
  1991年   2931篇
  1990年   2747篇
  1989年   2660篇
  1988年   2603篇
  1987年   2542篇
  1986年   2558篇
  1985年   3358篇
  1984年   3418篇
  1983年   2864篇
  1982年   3102篇
  1981年   2848篇
  1980年   2655篇
  1979年   2835篇
  1978年   3060篇
  1977年   3070篇
  1976年   3109篇
  1975年   2831篇
  1974年   2954篇
  1973年   2995篇
  1972年   2351篇
  1971年   1865篇
排序方式: 共有10000条查询结果,搜索用时 140 毫秒
11.
Physics of the Solid State - Local internal stresses in two natural inhomogeneous materials differing in the structure have been calculated using analysis of pauses between acoustic emission...  相似文献   
12.
Crystallography Reports - Two LiInSe2 single crystals, grown under different conditions, have been studied. Characteristics of these crystals for neutron detection have been compared using...  相似文献   
13.
Journal of Radioanalytical and Nuclear Chemistry - In this paper a study for the selection of an NPE (nonylphenol ethoxylates)—free cocktail is discussed in order to be used for our routine...  相似文献   
14.
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   
15.
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   
16.
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   
17.
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   
18.
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   
19.
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   
20.
Crystallography Reports - Methods of coherent X-ray diffraction imaging of the spatial structure of noncrystalline objects and nanocrystals (nanostructures) are considered. Particular attention is...  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