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   9871篇
  免费   1959篇
  国内免费   1513篇
化学   7218篇
晶体学   190篇
力学   618篇
综合类   125篇
数学   1262篇
物理学   3930篇
  2024年   7篇
  2023年   216篇
  2022年   283篇
  2021年   361篇
  2020年   522篇
  2019年   443篇
  2018年   412篇
  2017年   352篇
  2016年   474篇
  2015年   498篇
  2014年   622篇
  2013年   753篇
  2012年   877篇
  2011年   943篇
  2010年   677篇
  2009年   633篇
  2008年   641篇
  2007年   594篇
  2006年   586篇
  2005年   470篇
  2004年   377篇
  2003年   288篇
  2002年   353篇
  2001年   254篇
  2000年   248篇
  1999年   215篇
  1998年   156篇
  1997年   141篇
  1996年   153篇
  1995年   121篇
  1994年   111篇
  1993年   82篇
  1992年   89篇
  1991年   68篇
  1990年   62篇
  1989年   58篇
  1988年   45篇
  1987年   28篇
  1986年   34篇
  1985年   27篇
  1984年   18篇
  1983年   6篇
  1982年   7篇
  1981年   11篇
  1980年   11篇
  1979年   2篇
  1965年   2篇
  1957年   3篇
  1930年   3篇
  1922年   1篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
1.
Liu  Shao-Hua  Tian  Bo 《Nonlinear dynamics》2022,108(3):2471-2482
Nonlinear Dynamics - In this paper, a (2+1)-dimensional Caudrey–Dodd–Gibbon–Kotera–Sawada system is investigated in fluid mechanics via the symbolic computation. With the...  相似文献   
2.
Journal of Nanoparticle Research - Polycrystalline metallic copper nanoparticle samples with the average particle sizes ranging from 53 to 80 nm were controllably prepared by the wet...  相似文献   
3.
Tang  Yixuan  Tian  Qiang  Hu  Haiyan 《Nonlinear dynamics》2022,109(4):2319-2354
Nonlinear Dynamics - To describe the particular mechanical behaviors of beams with both uniform and non-uniform cross sections, such as the bidirectional bending, torsion-bending coupling, the...  相似文献   
4.
5.
Xu  Yifan  Zhang  Hehe  Ding  Tangjing  Tian  Ruiqi  Sun  Dongmei  Wang  Ming-Sheng  Zhou  Xiaosi 《中国科学:化学(英文版)》2022,65(9):1807-1816
Science China Chemistry - Due to their enormous potential for large-scale energy storage, rechargeable potassium-ion batteries have been widely researched and developed. However, the drastic volume...  相似文献   
6.
Theoretical and Mathematical Physics - We theoretically calculate general higher-order soliton solutions of the space-shifted parity–time-symmetric nonlocal multicomponent nonlinear...  相似文献   
7.
Theoretical and Mathematical Physics - Starting from a $$5\times 5$$ local matrix $$\bar\partial$$ -problem, we successfully use the $$\bar\partial$$ -dressing method to derive a hierarchy of...  相似文献   
8.
Huo  Donghui  Wang  Hongzhao  Qin  Zijian  Tian  Yujia  Yan  Aixia 《Molecular diversity》2022,26(3):1715-1730
Molecular Diversity - Epidermal growth factor receptor (EGFR) has received widespread attention because it is an important target for anticancer drug design. Mutations in the EGFR, especially the...  相似文献   
9.
A rapid and sensitive method was developed and validated for the quantitative determination of xanthopurpurin (XPP) in rat plasma using ultra-performance liquid chromatography-electrospray ionization-Orbitrap mass spectrometry. XPP inhibits IgE production and prevents peanut-induced anaphylaxis. The XPP and emodin (internal standard) were determined in negative ion mode with m/z 239.0350 → 211.0400 and 269.0455 → 241.0507, respectively. The separation process was achieved using an ACQUITY UPLC HSS T3 column with acetonitrile and 0.1% formic acid in water (85:15). The linear range was 0.5–100 ng/mL, and the correlation coefficient (r2) was > 0.993. The inter-day and intra-day precision was within an acceptable range of 15%. The extraction recovery and matrix effect were 78.9–87.2% and 94.3–98.5%, respectively. Under different conditions, the XPP was stable in the range of 5.6–10.6%. This method was successfully applied to study the pharmacokinetics of XPP with an oral dose of 10.0 mg/kg and intravenous dose of 2.0 mg/kg in rats. The absolute oral bioavailability of XPP was 4.6%.  相似文献   
10.
The precise synthesis of poly(thioester)s with diverse structures is still a significant challenge in the polymeric materials field. Herein, we report a novel approach to the synthesis of well‐defined poly(thioester)s by the controlled alternating copolymerization of cyclic thioanhydrides and episulfides induced by simple organic ammonium salts. Both the cation and anion have strong effects on the copolymerization. [PPN]OAc ([PPN]=bis(triphenylphosphine)iminium) with a bulky cation was proven to be efficient in initiating this polymerization, yielding poly(thioester)s with a completely alternating structure, controlled molecular weight, and narrow polydispersity. The poly(thioester) obtained from succinic thioanhydride and propylene sulfide is a typical semicrystalline material, possessing a high refractive index of up to 1.78. Because it uses readily available monomers, this method is expected to open up a new route to poly(thioester)s with diverse structures and properties.  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