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   572篇
  免费   66篇
  国内免费   1篇
  639篇
  2022年   7篇
  2021年   8篇
  2019年   4篇
  2018年   8篇
  2017年   5篇
  2016年   15篇
  2015年   36篇
  2014年   29篇
  2013年   38篇
  2012年   36篇
  2011年   49篇
  2010年   22篇
  2009年   25篇
  2008年   31篇
  2007年   27篇
  2006年   26篇
  2005年   22篇
  2004年   18篇
  2003年   24篇
  2002年   19篇
  2001年   20篇
  2000年   17篇
  1999年   14篇
  1998年   6篇
  1997年   7篇
  1996年   4篇
  1995年   5篇
  1993年   3篇
  1992年   3篇
  1991年   7篇
  1990年   4篇
  1989年   7篇
  1988年   8篇
  1987年   4篇
  1986年   7篇
  1985年   4篇
  1983年   3篇
  1982年   4篇
  1981年   4篇
  1979年   11篇
  1978年   7篇
  1976年   2篇
  1975年   2篇
  1974年   3篇
  1973年   11篇
  1972年   3篇
  1971年   3篇
  1969年   2篇
  1968年   2篇
  1966年   2篇
排序方式: 共有639条查询结果,搜索用时 0 毫秒
611.
612.
613.
614.
Low-angle X-ray scattering curves of isolated calf thymus chromatin, dissolved in 0.2 mm EDTA, 0.2 mm MgCl2 or 0.5 m NaCl, have been analysed by comparison with simulated scattering curves of models from chromatin subunits and higher order structure. The results provided additional data based on established models. Assuming the protein core as a cylinder of 5.9–6.0 nm diameter and 5.9-2.0 nm height, the centre to centre distance of the cores in tightly packed chromatin was found to be 6.7 nm. Computer simulation of X-ray scattering of chromatin was fitted to experimentally derived data for estimating the ratios of quaternary and tertiary structure. Slight differences of the quaternary structures of 0.15 m NaCl adn in 0.2 mm MgCl2 were observed.  相似文献   
615.
Intensities of x-ray scattering from rabbit muscle sarcoplasmic reticulum membrane have been measured over the range of s = 0.05-0.25, at solvent densities varying between p0 = 0.335 and 0.389 electrons/A3. Analysis of the results shows agreement with the elements of structure deduced earlier by a different technique, based on the variation of the lipid-protein concentration ratio. In addition, the present work extends the analysis to allow isolation of the lipid contribution to the total scattering, from which a profile of the lipid electron density normal to the membrane face is evaluated. The scattering arising from electron correlations within the plane of the bilayer has also been identified.  相似文献   
616.
617.
In a multicenter randomized trial, the efficacy and safety of two streptokinase (SK) dosage regimens have been evaluated in patients with proximal deep vein thrombosis of inferior limbs. Twenty-nine patients received SK by a continuous intravenous infusion (250,000 IU as initial dose, 100,000 IU/h as maintenance dose), and 26 patients were treated with intermittent SK administration (500,000 IU as initial dose, followed by 250,000 IU every 12 h). Thrombolytic therapy was continued for 4 days, then the patients received heparin for 5 days and oral anticoagulant for 3 months. The results of treatment as judged by phlebographic examinations were similar in the two groups. Complete, substantial or partial thrombolysis was achieved in 52% of patients in the continuous infusion group and in 58% of patients in the intermittent treatment group. During SK administration, major bleeding complications occurred in 6 patients treated by continuous infusion and in 2 of the second group. The results showed that the intermittent SK administration is as effective and safe as the method of continuous SK infusion in the treatment of deep vein thrombosis.  相似文献   
618.
Vesicle-45Ca2+ ion flux and planar lipid bilayer single-channel measurements have shown that the Ca2+ release channel of skeletal muscle sarcoplasmic reticulum (SR) is activated by micromolar concentrations of Cibacron Blue F3A-G (Reactive Blue 2) and Reactive Red 120. Cibacron Blue increased the 45Ca2+ efflux rate from heavy SR vesicles by apparently interacting with both the adenine nucleotide and caffeine activating sites of the channel. Dye-induced 45Ca2+ release was inhibited by Mg2+ and ruthenium red. In single channel recordings with the purified channel protein complex, Cibacron Blue increased the open time of the Ca2+ release channel without an apparent change in the conductance of the main and subconductance states of the channel.  相似文献   
619.
620.
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