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   117334篇
  免费   935篇
  国内免费   417篇
化学   55643篇
晶体学   1604篇
力学   5465篇
综合类   13篇
数学   18996篇
物理学   36965篇
  2022年   635篇
  2021年   1025篇
  2020年   1076篇
  2019年   1288篇
  2018年   3572篇
  2017年   3912篇
  2016年   3299篇
  2015年   1842篇
  2014年   2469篇
  2013年   4456篇
  2012年   6593篇
  2011年   6017篇
  2010年   4586篇
  2009年   4390篇
  2008年   3762篇
  2007年   3647篇
  2006年   3543篇
  2005年   8643篇
  2004年   8156篇
  2003年   5488篇
  2002年   2777篇
  2001年   2569篇
  2000年   1805篇
  1999年   1475篇
  1998年   1272篇
  1997年   1146篇
  1996年   966篇
  1995年   905篇
  1994年   884篇
  1993年   868篇
  1992年   1054篇
  1991年   1100篇
  1990年   1017篇
  1989年   1032篇
  1988年   935篇
  1987年   835篇
  1986年   789篇
  1985年   923篇
  1984年   1009篇
  1983年   861篇
  1982年   868篇
  1981年   784篇
  1980年   726篇
  1979年   811篇
  1978年   927篇
  1977年   940篇
  1976年   897篇
  1975年   821篇
  1974年   836篇
  1973年   813篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Journal of Experimental and Theoretical Physics - Dzyaloshinskii–Moriya interaction, DMI in short, represents an antisymmetric type of magnetic interactions that favor orthogonal orientation...  相似文献   
2.
Russian Journal of General Chemistry - Aminophosphabetaines, i.e., isobutyl {[alkyl(dimethyl)ammonio]methyl}phosphonates with higher alkyl substituents at the nitrogen atom, were obtained by a...  相似文献   
3.
Kinetics and Catalysis - The results of studies in the field of synthesis and characterization of layered double hydroxides (LDHs) obtained using solid-phase reactions are summarized. The effect of...  相似文献   
4.
Mechanics of Composite Materials - Carbon fiber (CF)/ polyamide (PA6) composites are one of the most promising thermoplastic materials for automobile applications. However, the interfacial...  相似文献   
5.
Russian Journal of Applied Chemistry - A method for the disposal of hydrolysis lignin waste based on its modification with ZnCl2 and FeCl3 and subsequent carbonization at 800°C was proposed....  相似文献   
6.
Mathematical Notes - Subspaces of the space of analytic functions on a convex domain in the complex plane that are invariant with respect to the differentiation operator are studied. The problem of...  相似文献   
7.
Russian Physics Journal - The specific features of the sorption activity of silver nanoparticles (AgNPs) on biodegradable polymers of natural (collagen) and artificial (polyamide 6.6) origin have...  相似文献   
8.
General Relativity and Gravitation - In previous work, we established theoretical results concerning the effect of matter shells surrounding a gravitational wave (GW) source, and we now apply these...  相似文献   
9.
The health monitoring has been studied to ensure integrity of design of engine structure by detection, quantification, and prediction of damages. Early detection of faults may allow the downtime of maintenance to be rescheduled, thus preventing sudden shutdown of machines. In cylinder pressure developed, vibrations and noise emissions data provide a rich source of information about condition of engines. Monitoring of vibrations and noise emissions are novel non-intrusive methodologies for which positioning of various transducers are important issue. The presented work shows applicability of these diagnosis methodologies adopted in case of diesel engines. The effects of changing various fuel injection parameters was analyzed. Scope of using non-intrusive technique has been analyzed by changing locations of microphone. Novelty of this worklies in exploring signal processing methods for various locations around the engine test set up. Various frequency ranges of contributing noise and vibration sources were identified. Time-Frequency analysis showed the onset of various cyclic. Based on the identification of various frequency bands, it is possible to device suitable filters in order to extract more information.  相似文献   
10.
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   
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