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   441050篇
  免费   4572篇
  国内免费   1143篇
化学   231917篇
晶体学   6797篇
力学   20158篇
综合类   13篇
数学   51670篇
物理学   136210篇
  2020年   3742篇
  2019年   4113篇
  2018年   5481篇
  2017年   5344篇
  2016年   7998篇
  2015年   4919篇
  2014年   7624篇
  2013年   18879篇
  2012年   14734篇
  2011年   17738篇
  2010年   12487篇
  2009年   12137篇
  2008年   16381篇
  2007年   16639篇
  2006年   15607篇
  2005年   14049篇
  2004年   12898篇
  2003年   11636篇
  2002年   11352篇
  2001年   12484篇
  2000年   9677篇
  1999年   7484篇
  1998年   6385篇
  1997年   6323篇
  1996年   5934篇
  1995年   5520篇
  1994年   5526篇
  1993年   5199篇
  1992年   5853篇
  1991年   5889篇
  1990年   5694篇
  1989年   5364篇
  1988年   5495篇
  1987年   5433篇
  1986年   5120篇
  1985年   6834篇
  1984年   7221篇
  1983年   5988篇
  1982年   6289篇
  1981年   6178篇
  1980年   6039篇
  1979年   6081篇
  1978年   6438篇
  1977年   6372篇
  1976年   6458篇
  1975年   5966篇
  1974年   6029篇
  1973年   6267篇
  1972年   4293篇
  1971年   3508篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
31.
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   
32.
A formal computation proving a new operator identity from known ones is, in principle, restricted by domains and codomains of linear operators involved, since not any two operators can be added or composed. Algebraically, identities can be modelled by noncommutative polynomials and such a formal computation proves that the polynomial corresponding to the new identity lies in the ideal generated by the polynomials corresponding to the known identities. In order to prove an operator identity, however, just proving membership of the polynomial in the ideal is not enough, since the ring of noncommutative polynomials ignores domains and codomains. We show that it suffices to additionally verify compatibility of this polynomial and of the generators of the ideal with the labelled quiver that encodes which polynomials can be realized as linear operators. Then, for every consistent representation of such a quiver in a linear category, there exists a computation in the category that proves the corresponding instance of the identity. Moreover, by assigning the same label to several edges of the quiver, the algebraic framework developed allows to model different versions of an operator by the same indeterminate in the noncommutative polynomials.  相似文献   
33.
Crystallography Reports - The crystal and molecular structures of Cl–C6H4–O–C16H33 (I) have been studied, and its differential scanning calorimetry (DSC) study is performed....  相似文献   
34.
35.
Doklady Physics - This work is devoted to analysis and generalization of the kinetic criteria of vitrification using the model of delocalized atoms. The generalized criterion of a...  相似文献   
36.
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   
37.
Journal of Experimental and Theoretical Physics - The studies of the topological properties of systems have recently been extended due to a new concept of higher-order topological insulators and...  相似文献   
38.
39.
CRANAD-2 is a fluorogenic curcumin derivative used for near-infrared detection and imaging in vivo of amyloid aggregates, which are involved in neurodegenerative diseases. We explore the performance of CRANAD-2 in two super-resolution imaging techniques, namely stimulated emission depletion (STED) and single-molecule localization microscopy (SMLM), with markedly different fluorophore requirements. By conveniently adapting the concentration of CRANAD-2, which transiently binds to amyloid fibrils, we show that it performs well in both techniques, achieving a resolution in the range of 45–55 nm. Correlation of SMLM with atomic force microscopy (AFM) validates the resolution of fine features in the reconstructed super-resolved image. The good performance and versatility of CRANAD-2 provides a powerful tool for near-infrared nanoscopic imaging of amyloids in vitro and in vivo.  相似文献   
40.
Journal of Analytical Chemistry - Silver nanoparticles modified with Eu3+ ions increase the intensity of the fluorescence signal by a factor of 125 in an analytical system containing doxycycline as...  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