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   92894篇
  免费   3250篇
  国内免费   3293篇
化学   35598篇
晶体学   1081篇
力学   7628篇
综合类   245篇
数学   33794篇
物理学   21091篇
  2023年   334篇
  2022年   468篇
  2021年   594篇
  2020年   781篇
  2019年   798篇
  2018年   10959篇
  2017年   10833篇
  2016年   6892篇
  2015年   1774篇
  2014年   1323篇
  2013年   1701篇
  2012年   5161篇
  2011年   11877篇
  2010年   6706篇
  2009年   7067篇
  2008年   7687篇
  2007年   9642篇
  2006年   1029篇
  2005年   2046篇
  2004年   2132篇
  2003年   2443篇
  2002年   1501篇
  2001年   646篇
  2000年   619篇
  1999年   445篇
  1998年   396篇
  1997年   310篇
  1996年   386篇
  1995年   266篇
  1994年   226篇
  1993年   213篇
  1992年   137篇
  1991年   169篇
  1990年   149篇
  1989年   109篇
  1988年   99篇
  1987年   88篇
  1986年   94篇
  1985年   90篇
  1984年   59篇
  1983年   59篇
  1982年   51篇
  1981年   45篇
  1980年   54篇
  1979年   46篇
  1914年   45篇
  1913年   40篇
  1912年   40篇
  1909年   41篇
  1908年   40篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
International Journal of Theoretical Physics - We investigate the monogamy relations related to the concurrence, the entanglement of formation, convex-roof extended negativity, Tsallis-q...  相似文献   
2.

We study the Bell nonlocality of high dimensional quantum systems based on quantum entanglement. A quantitative relationship between the maximal expectation value B of Bell operators and the quantum entanglement concurrence C is obtained for even dimension pure states, with the upper and lower bounds of B governed by C.

  相似文献   
3.
Song  Zi-Long  Zhu  Yun  Liu  Jing-Rui  Guo  Shu-Ke  Gu  Yu-Cheng  Han  Xinya  Dong  Hong-Qiang  Sun  Qi  Zhang  Wei-Hua  Zhang  Ming-Zhi 《Molecular diversity》2021,25(1):205-221
Molecular Diversity - Based on the strategy of diversity-oriented synthesis and the structures of natural product pimprinine and streptochlorin, two series of novel pimprinine derivatives...  相似文献   
4.
Guo  Jiayun  Ma  Dongge  Sun  Fulin  Zhuang  Guilin  Wang  Qi  Al-Enizi  Abdullah M.  Nafady  Ayman  Ma  Shengqian 《中国科学:化学(英文版)》2022,65(9):1704-1709
Science China Chemistry - The heterojunction constructed of covalent organic frameworks (COFs) with adjustable structure and other photocatalysts has great potential in the field of photocatalysis....  相似文献   
5.
3,4-Difluorobenzyl(1-ethyl-5-(4-((4-hydroxypiperidin-1-yl)-methyl)thiazol-2-yl)-1H-indol-3-yl)carbamate (NAI59), a small molecule with outstanding therapeutic effectiveness to anti-pulmonary fibrosis, was developed as an autotaxin inhibitor candidate compound. To evaluate the pharmacokinetics and plasma protein binding of NAI59, a UPLC–MS/MS method was developed to quantify NAI59 in plasma and phosphate-buffered saline. The calibration curve linearity ranged from 9.95 to 1990.00 ng/mL in plasma. The accuracy was −6.8 to 5.9%, and the intra- and inter-day precision was within 15%. The matrix effect and recovery, as well as dilution integrity, were within the criteria. The chromatographic and mass spectrometric conditions were also feasible to determine phosphate-buffered saline samples, and it has been proved that this method exhibits good precision and accuracy in the range of 9.95–497.50 ng/mL in phosphate-buffered saline. This study is the first to determine the pharmacokinetics, absolute bioavailability, and plasma protein binding of NAI59 in rats using this established method. Therefore, the pharmacokinetic profiles of NAI59 showed a dose-dependent relationship after oral administration, and the absolute bioavailability in rats was 6.3%. In addition, the results of protein binding showed that the combining capacity of NAI59 with plasma protein attained 90% and increased with the increase in drug concentration.  相似文献   
6.
Research on Chemical Intermediates - Owing to the simultaneous utilization of photogenerated electrons and holes, coupling light-driven hydrogen (H2) evolution reaction (HER) and biomass-derived...  相似文献   
7.
Journal of Radioanalytical and Nuclear Chemistry - To analyze the effect of scintillator detectors on the fast neutron multiplicity, this paper uses Geant4 and Matlab to simulate and study three...  相似文献   
8.
Refractory wounds have always been an important issue to healthcare systems, whose healing process is always delayed by multiple factors, including bacterial infections, chronic inflammation, and excessive exudates, etc. Employing multifunctional wound dressings is recognized as an effective strategy to deal with refractory wounds, which has yielded promising outcomes in recent years. Among these advanced wound dressings, fibrous dressings have gained growing attention due to their unique merits. Such wound dressings have demonstrated great potential in delivering theranostic agents, such as antibacterial agents, anti-inflammatory drugs, growth factors, and diagnostic probes, etc., for the purposes of accelerating wound healing. This paper reviews the development of multifunctional fibrous dressings and their applications in treating refractory wounds. The construction approaches of novel fibrous dressing with capabilities of antibacterial, anti-inflammation, exudate management and diagnosis were also introduced. Furthermore, the existing problems and challenges are also discussed briefly.  相似文献   
9.
Journal of Applied Mechanics and Technical Physics - A self-equilibrated stress field for an incompressible sphere is constructed based on a non-Euclidean continuum model. The...  相似文献   
10.
Liu  Jingze  Fei  Qingguo  Wu  Shaoqing  Tang  Zhenhuan  Zhang  Dahai 《Nonlinear dynamics》2021,106(3):1869-1890
Nonlinear Dynamics - Rolling bearing and squeeze film damper will introduce structural nonlinearity into the dynamic model of aeroengine. Rubbing will occur due to the clearance reduction design of...  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