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   2091篇
  免费   97篇
  国内免费   3篇
  2191篇
  2023年   13篇
  2022年   24篇
  2021年   46篇
  2020年   36篇
  2019年   39篇
  2018年   46篇
  2017年   28篇
  2016年   62篇
  2015年   86篇
  2014年   93篇
  2013年   140篇
  2012年   141篇
  2011年   177篇
  2010年   89篇
  2009年   79篇
  2008年   104篇
  2007年   105篇
  2006年   106篇
  2005年   100篇
  2004年   78篇
  2003年   72篇
  2002年   71篇
  2001年   35篇
  2000年   31篇
  1999年   34篇
  1998年   17篇
  1997年   14篇
  1996年   12篇
  1995年   17篇
  1994年   11篇
  1993年   15篇
  1992年   26篇
  1991年   20篇
  1990年   17篇
  1989年   20篇
  1988年   23篇
  1987年   15篇
  1986年   14篇
  1985年   17篇
  1984年   11篇
  1983年   10篇
  1982年   11篇
  1981年   10篇
  1980年   10篇
  1979年   8篇
  1978年   8篇
  1977年   8篇
  1976年   6篇
  1974年   9篇
  1967年   5篇
排序方式: 共有2191条查询结果,搜索用时 0 毫秒
41.
42.
The structural and spectroscopic properties of novel five-coordinated dimeric-Cu(II) system have been investigated. The biocidal activities of all eight compounds, ligands, cupric nitrate and standard drugs against six bacteria and three fungi were determined. The DNA interaction activity of complexes was studied using spectrophotometry and electrophoresis. The superoxide dismutase (SOD)-like activity of the complexes was compared with previously reported monomeric- and dimeric copper complexes. The results support the five-coordinated dimeric square pyramidal geometry for the quinolone-Cu(II) system.  相似文献   
43.
Patients with chronic alcoholism and/or Alzheimer's disease show degenerative changes in the cerebral cortex and hippocampus. To investigate possible changes in insulin-like growth factor I receptor binding sites in brain tissue of patients with these pathological conditions, the number of 125I-insulin-like growth factor I binding sites was determined in tissues obtained from control patients and those with Alzheimer's and/or with a history of alcoholism. The four experimental groups examined consisted of patients from similar age groups. Postmortem histology and a clinical history were used for the diagnosis of Alzheimer's disease and alcoholism, respectively. Careful clinical records were kept concerning other variables such as immediate cause of death and medications administered before death. Specific binding of 125I-insulin-like growth factor I to homogenates prepared from cerebral cortex of Alzheimer's, alcoholic, alcoholic Alzheimer's, and age-matched control patients was similar, although Alzheimer's patients tended to have slightly higher binding values. No significant differences in insulin-like growth factor I binding in cerebral cortex were found with regard to age of patients, the interval between death and autopsy, and CNS-active medications. No statistical differences in 125I-insulin-like growth factor I binding were noted in hippocampal tissue from the four patient groups. Thus, human insulin-like growth factor I binding sites in cerebral cortex and hippocampus appear unaffected by several variables.  相似文献   
44.
Screening of fifteen nutrients belonging to four categories, viz., carbon, nitrogen, salt and complex organic sources was carried out using Plackett-Burman design for the production of thermostable #-amylase and pullulanase by Clostridium thermosulfurogenes SV2 in solid-state fermentation (SSF). This design involves screening of up to `nу' variables in just `n' number of experiments. Regression co-efficients and t-values were calculated by subjecting the experimental data to statistical analysis. Lactose, diammonium hydrogen phosphate, calcium chloride and casein hydrolysate showed higher regression co-efficients in the biomass formation. Among the fifteen nutrients screened, based on their performance in terms of product promoting ability, availability and cost, magnesium chloride, potato starch, ferrous sulphate, pearl millet flour and corn steep liquor were identified as most effective and, therefore, selected for inclusion in further optimization studies.  相似文献   
45.
The diversity of natural enemies harboured by flowering forbs on rice field bunds was recorded. Ageratum conozoides with a maximum Shannon diversity index of 1.8 followed by Acmella uliginosa, Eclipta alba and Tridax procumbens are amenable for ecological engineering, providing nectar, pollen and alternate prey to natural enemies.  相似文献   
46.
47.
48.
49.
Type 2 diabetes mellitus (T2DM) is linked with Glycogen synthase kinase-3 β.Therefore, it is ofinterest to document molecular docking analysis data of compounds from Justica adhatoda L with glycogen synthase kinase-3 β. We report the binding features of ethambutol, pyrazinamide, stigmasterol and vasicoline with GSK-3 β.  相似文献   
50.
Molecular and Cellular Biochemistry - β-cell dysfunction is a critical determinant for both type 1 diabetes and type 2 diabetes and β-cells are shown to be highly susceptible to cellular...  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