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   164篇
  免费   6篇
  国内免费   1篇
化学   101篇
晶体学   4篇
力学   5篇
数学   30篇
物理学   31篇
  2020年   3篇
  2019年   3篇
  2016年   5篇
  2014年   3篇
  2013年   26篇
  2012年   5篇
  2011年   6篇
  2010年   2篇
  2009年   2篇
  2008年   10篇
  2007年   4篇
  2006年   7篇
  2005年   7篇
  2004年   2篇
  2003年   9篇
  2002年   3篇
  1996年   1篇
  1995年   2篇
  1994年   1篇
  1992年   2篇
  1991年   1篇
  1989年   2篇
  1986年   2篇
  1985年   2篇
  1984年   4篇
  1983年   1篇
  1982年   8篇
  1981年   5篇
  1980年   3篇
  1979年   1篇
  1978年   3篇
  1977年   1篇
  1976年   3篇
  1975年   1篇
  1974年   2篇
  1972年   2篇
  1971年   1篇
  1970年   2篇
  1969年   2篇
  1968年   1篇
  1964年   1篇
  1963年   1篇
  1960年   1篇
  1959年   2篇
  1939年   1篇
  1936年   1篇
  1934年   2篇
  1933年   5篇
  1932年   1篇
  1929年   1篇
排序方式: 共有171条查询结果,搜索用时 31 毫秒
51.
Ion exchange membranes with carboxyl groups, which were insoluble in acidic and alkaline aqueous solutions, were prepared from poly(isobutylene-alternative co-maleic anhydride) and poly(vinyl alcohol). When a membrane, one side of which was alkaline, the other, acidic, was fixed in a diaphragm cell, it transported organic ions, such as amino acids and aniline, from the acidic to the alkaline side or vice versa. The passage of organic ions through the membrane was governed by an electrochemical interaction between carboxyl groups in the membrance and transporting ions. The direction of the organic ions depended on a pH difference between the two sides of the membrane.  相似文献   
52.
Cobalt-59 NMR chemical shifts of Co(acac)3, and Co(dpm)3 (acac = acetylacetonate ion and dpm = dipivaloylmethanate ion) in 14 organic solvents, C6H14, C6H6, CH2Cl2, CHCl3, CCl4, CH3CN, CH3OH, C2H5OH, CH3CH(OH)CH3, (C2H5)2O, (CH3)2CO, (CH3)2SO, (CH3)2NCHO and C6H5NO2, were measured at five temperatures ranging from 289 to 329 K. The observed chemical shift (obs) was linearly correlated to the maximum absorption wavelength in the visible spectra (max) corresponding to the d-d electronic transition energy between the ground 1A1g and excited 1T1g states. The obs-max relation was explained by the ligand field theory. The temperature coefficients of obs, of each complex showed a negative correlation with obs. The obs, of Co(acac)3 decreased with the increasing electrophilic ability of the solvent (Mayer's acceptor number), whereas no tendency was observed in the case of Co(dpm)3.  相似文献   
53.
54.
A new apparatus has been built that annexes a normal electrocardiograph, ECG, with the aim to enhance its capacity. It adds the normal ECG power to superpose multiple records of ECG altogether and averages out them and, further, makes sophisticated analysis, such as normalizing the peak heights, evaluating the half-line widths of the peaks, or that of the standard deviations of measurements like the inter peak distances. The results of the said calculations have not been obtainable using the former instruments, and are expected to be useful for clinicians.  相似文献   
55.
Effects of four anti-epileptic drugs (AED; phenobarbital, phenytoin, carbamazepine and sodium valproate) on the L-tryptophan binding to human serum albumin were studied. Among these drugs examined, only sodium valproate inhibited the binding even within the concentrations of its therapeutic range, and the Klotz plotting analysis revealed that the inhibition was competitive. The results of examinations with sera from epileptic patients medicated with these AED and drug-free normal controls also suggested that the protein binding ratios of L-tryptophan were decreased in the blood plasma of some patients with the high valproate concentrations and the low albumin contents.  相似文献   
56.
57.
Thermolyses of cage lactones (2) and their corresponding lactols (7) cause a formal dyotropic rearrangement. These novel reactions in cage system are discussed.  相似文献   
58.
59.
60.
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