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   825314篇
  免费   12118篇
  国内免费   4587篇
化学   422828篇
晶体学   11548篇
力学   41283篇
综合类   132篇
数学   116200篇
物理学   250028篇
  2021年   7161篇
  2020年   7880篇
  2019年   8602篇
  2018年   14732篇
  2017年   14969篇
  2016年   17565篇
  2015年   10086篇
  2014年   15048篇
  2013年   35538篇
  2012年   30306篇
  2011年   39689篇
  2010年   27432篇
  2009年   27235篇
  2008年   35893篇
  2007年   37575篇
  2006年   28468篇
  2005年   28440篇
  2004年   24712篇
  2003年   22458篇
  2002年   21244篇
  2001年   21793篇
  2000年   17061篇
  1999年   13434篇
  1998年   11389篇
  1997年   11142篇
  1996年   10870篇
  1995年   9749篇
  1994年   9508篇
  1993年   9098篇
  1992年   9813篇
  1991年   10162篇
  1990年   9645篇
  1989年   9430篇
  1988年   9430篇
  1987年   9045篇
  1986年   8635篇
  1985年   11404篇
  1984年   11775篇
  1983年   9849篇
  1982年   10465篇
  1981年   10005篇
  1980年   9538篇
  1979年   10137篇
  1978年   10394篇
  1977年   10238篇
  1976年   10182篇
  1975年   9752篇
  1974年   9501篇
  1973年   9952篇
  1972年   6763篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
52.
Siberian Mathematical Journal - A lattice homomorphism between quasi-Banach lattices is known to be compact if and only if it is a sum of a series of rank one lattice...  相似文献   
53.
Theoretical and Mathematical Physics - This paper is devoted to tetrahedron maps, which are set-theoretical solutions of the Zamolodchikov tetrahedron equation. We construct a family of tetrahedron...  相似文献   
54.
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   
55.
Computational Optimization and Applications - We consider a continuous-time optimization method based on a dynamical system, where a massive particle starting at rest moves in the conservative...  相似文献   
56.
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   
57.
Journal of Radioanalytical and Nuclear Chemistry - The simplified 8-oxide system (SiO2-B2O3-Na2O-Al2O3-CaO-TiO2-MoO3-La2O3) has been prepared under two types of cooling methods, and analyzed with...  相似文献   
58.
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   
59.
Journal of Russian Laser Research - We analyze the way of advancing to tender X-rays the short-wavelength bound of the operating range of flat-field grating spectrographs. We design two VLS grating...  相似文献   
60.
Li  Jun  Zheng  Dayong  Wei  Ning  Sun  Yunfeng  Liu  Li  Yuan  Yuan  Jiang  Qinghua 《Chemistry of Natural Compounds》2022,58(4):650-652
Chemistry of Natural Compounds - A new quassinoid, dehydrobruceantinol B (1), was isolated from the seeds of Brucea javanica, together with two known compounds, bruceantinol (2) and bruceine A (3)....  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