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   277967篇
  免费   19378篇
  国内免费   8074篇
化学   170928篇
晶体学   3552篇
力学   14388篇
综合类   522篇
数学   31019篇
物理学   85010篇
  2022年   3400篇
  2021年   4168篇
  2020年   5336篇
  2019年   6872篇
  2018年   6411篇
  2017年   6027篇
  2016年   10017篇
  2015年   7964篇
  2014年   10179篇
  2013年   15393篇
  2012年   13866篇
  2011年   14305篇
  2010年   11984篇
  2009年   12041篇
  2008年   12494篇
  2007年   11448篇
  2006年   10283篇
  2005年   9318篇
  2004年   8377篇
  2003年   7289篇
  2002年   7923篇
  2001年   7663篇
  2000年   6232篇
  1999年   4684篇
  1998年   3952篇
  1997年   3639篇
  1996年   3477篇
  1995年   3115篇
  1994年   3008篇
  1993年   2904篇
  1992年   2839篇
  1991年   3041篇
  1990年   2869篇
  1989年   2867篇
  1988年   2626篇
  1987年   2645篇
  1986年   2423篇
  1985年   2958篇
  1984年   2873篇
  1983年   2491篇
  1982年   2521篇
  1981年   2385篇
  1979年   2442篇
  1978年   2600篇
  1977年   2689篇
  1976年   2779篇
  1975年   2594篇
  1974年   2517篇
  1973年   2690篇
  1972年   2180篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
The contribution of rheological properties and viscoelasticity of the interfacial adsorbed layer to the emulsification mechanism of enzymatic modified sugar beet pectin (SBP) was studied. The component content of each enzymatic modified pectin was lower than that of untreated SBP. Protein and ferulic acid decreased from 5.52% and 1.08% to 0.54% and 0.13%, respectively, resulting in a decrease in thermal stability, apparent viscosity, and molecular weight (Mw). The dynamic interfacial rheological properties showed that the interfacial pressure and modulus (E) decreased significantly with the decrease of functional groups (especially proteins), which also led to the bimodal distribution of particle size. These results indicated that the superior emulsification property of SBP is mainly determined by proteins, followed by ferulic acid, and the existence of other functional groups also promotes the emulsification property of SBP.  相似文献   
132.
Wu  Xuze  Sun  Yu  Wang  Yu  Chen  Yu 《Nonlinear dynamics》2020,99(3):1937-1958
Nonlinear Dynamics - Oblique collisions are more likely to happen in the realistic translational joint with clearance, compared to the full front impacts. It can be a quite demanding task to...  相似文献   
133.
134.
Molecular dynamics simulation was performed to study the formation of cluster structure, interfaces, and surfaces with different curvature radii in a perfect nanocrystal passed through by a nonlinear wave. It is shown that this process is a type of nanostructure self-organization in response to an external energy flux with subsequent development of a strong rotational field.  相似文献   
135.
Chen  Haiyang  Gao  Fangzheng 《Nonlinear dynamics》2022,108(2):1319-1338
Nonlinear Dynamics - Based on a mixed control strategy, this study addresses the finite-time stabilization with extended dissipativity for Markov jump systems (MJSs) with unreliable...  相似文献   
136.
Journal of Experimental and Theoretical Physics - The nature of the training effect in exchange-biased compounds is studied. This effect consists in a decrease in the exchange bias field (HEB)...  相似文献   
137.
Journal of Solid State Electrochemistry - Due to their distinctive chemical, electronic, and environmental properties, polypyrrole is used as a blocking barrier for methanol leakage in direct...  相似文献   
138.
Popel  S. I.  Golub’  A. P. 《JETP Letters》2022,115(10):596-601
JETP Letters - One of the main features of the dusty plasma compared to the conventional plasma (without charged dust particles is anomalous dissipation that is caused by the charging of dust...  相似文献   
139.
Russian Journal of General Chemistry - Highly dispersed CaO has been synthesized by heating an aqueous solution of calcium nitrate and D-glucose up to 800°C. Calcium oxide is formed with an...  相似文献   
140.

In this paper, we study the Cauchy problem for the Benjamin-Ono-Burgers equation \({\partial _t}u - \epsilon \partial _x^2u + {\cal H}\partial _x^2u + u{u_x} = 0\), where \({\cal H}\) denotes the Hilbert transform operator. We obtain that it is uniformly locally well-posed for small data in the refined Sobolev space \({\tilde H^\sigma }(\mathbb{R})\,\,(\sigma \geqslant 0)\), which is a subspace of L2(ℝ). It is worth noting that the low-frequency part of \({\tilde H^\sigma }(\mathbb{R})\) is scaling critical, and thus the small data is necessary. The high-frequency part of \({\tilde H^\sigma }(\mathbb{R})\) is equal to the Sobolev space Hσ (ℝ) (σ ⩾ 0) and reduces to L2(ℝ). Furthermore, we also obtain its inviscid limit behavior in \({\tilde H^\sigma }(\mathbb{R})\) (σ ⩾ 0).

  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