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   197152篇
  免费   3361篇
  国内免费   397篇
化学   110790篇
晶体学   2234篇
力学   8081篇
综合类   7篇
数学   22582篇
物理学   57216篇
  2021年   1436篇
  2020年   1732篇
  2019年   1760篇
  2018年   2405篇
  2017年   2215篇
  2016年   3853篇
  2015年   2846篇
  2014年   3710篇
  2013年   9004篇
  2012年   8058篇
  2011年   9446篇
  2010年   6140篇
  2009年   5802篇
  2008年   8383篇
  2007年   8466篇
  2006年   7794篇
  2005年   7302篇
  2004年   6392篇
  2003年   5441篇
  2002年   5281篇
  2001年   5083篇
  2000年   3952篇
  1999年   3019篇
  1998年   2594篇
  1997年   2510篇
  1996年   2399篇
  1995年   2150篇
  1994年   2203篇
  1993年   2050篇
  1992年   2340篇
  1991年   2407篇
  1990年   2196篇
  1989年   2193篇
  1988年   2090篇
  1987年   1977篇
  1986年   1887篇
  1985年   2542篇
  1984年   2640篇
  1983年   2128篇
  1982年   2380篇
  1981年   2249篇
  1980年   2143篇
  1979年   2282篇
  1978年   2428篇
  1977年   2270篇
  1976年   2361篇
  1975年   2238篇
  1974年   2304篇
  1973年   2284篇
  1972年   1455篇
排序方式: 共有10000条查询结果,搜索用时 531 毫秒
11.
Set-Valued and Variational Analysis - R. Tyrell Rockafellar and his collaborators introduced, in a series of works, new regression modeling methods based on the notion of superquantile (or...  相似文献   
12.
Faul  Peter F. 《Semigroup Forum》2021,102(3):655-673
Semigroup Forum - It is well known that the set of isomorphism classes of extensions of groups with abelian kernel is characterized by the second cohomology group. In this paper we generalise this...  相似文献   
13.
Ferrarini  A.  Finotello  A.  Salsano  G.  Auricchio  F.  Palombo  D.  Spinella  G.  Pane  B.  Conti  M. 《Acta Mechanica Sinica》2021,37(7):1192-1192
Acta Mechanica Sinica - A Correction to this paper has been published: https://doi.org/10.1007/s10409-021-01066-2  相似文献   
14.
15.
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   
16.
Russian Chemical Bulletin - The N-methylation of primary carboxamides is based on two consecutive reactions. The silylation of the corresponding carboxamides with chloro(chloromethyl)dimethylsilane...  相似文献   
17.
18.
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   
19.
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   
20.
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   
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