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   947篇
  免费   44篇
  2023年   10篇
  2022年   27篇
  2021年   29篇
  2020年   12篇
  2019年   24篇
  2018年   29篇
  2017年   20篇
  2016年   30篇
  2015年   38篇
  2014年   51篇
  2013年   69篇
  2012年   87篇
  2011年   81篇
  2010年   34篇
  2009年   30篇
  2008年   42篇
  2007年   44篇
  2006年   38篇
  2005年   22篇
  2004年   21篇
  2003年   25篇
  2002年   16篇
  2001年   19篇
  2000年   17篇
  1999年   13篇
  1998年   5篇
  1997年   4篇
  1996年   4篇
  1995年   4篇
  1993年   4篇
  1992年   11篇
  1991年   7篇
  1990年   10篇
  1989年   6篇
  1988年   5篇
  1987年   6篇
  1986年   7篇
  1985年   12篇
  1984年   8篇
  1983年   3篇
  1982年   7篇
  1981年   5篇
  1980年   5篇
  1979年   8篇
  1978年   6篇
  1977年   5篇
  1975年   5篇
  1974年   5篇
  1973年   6篇
  1971年   4篇
排序方式: 共有991条查询结果,搜索用时 31 毫秒
981.
cAMP and cGMP contents were determined in the skeletal and cardiac muscle of normal and dystrophic mice. cAMP content increased in the dystrophic muscle at every stage of the disease whereas cGMP content decreased in the preliminary stages and increased at the terminal stage of the disease. The content of both nucleotides per heart was not affected in murine dystrophy. Thus, levels of cyclic nucleotides appear to be selectively altered in dystrophic skeletal muscle.  相似文献   
982.
983.
Archives of Microbiology - Lactobacillus plantarum DMR17 was isolated from homemade cow dahi of Sikkim Himalayan region of India. Here, we report the draft genome sequence of this strain. A total...  相似文献   
984.
Molecular Biology Reports - Hypoxic injury to retinal ganglionic cells and adjoining glia is implicated in glaucomatous optic neuropathy. The present study evaluates the effect of IL-6 on R28...  相似文献   
985.
SARS Coronavirus 2 (SARS-CoV-2) emerged in late 2019, leading to the Coronavirus Disease 2019 (COVID-19) pandemic that continues to cause significant global mortality in human populations. Given its sequence similarity to SARS-CoV, as well as related coronaviruses circulating in bats, SARS-CoV-2 is thought to have originated in Chiroptera species in China. However, whether the virus spread directly to humans or through an intermediate host is currently unclear, as is the potential for this virus to infect companion animals, livestock, and wildlife that could act as viral reservoirs. Using a combination of surrogate entry assays and live virus, we demonstrate that, in addition to human angiotensin-converting enzyme 2 (ACE2), the Spike glycoprotein of SARS-CoV-2 has a broad host tropism for mammalian ACE2 receptors, despite divergence in the amino acids at the Spike receptor binding site on these proteins. Of the 22 different hosts we investigated, ACE2 proteins from dog, cat, and cattle were the most permissive to SARS-CoV-2, while bat and bird ACE2 proteins were the least efficiently used receptors. The absence of a significant tropism for any of the 3 genetically distinct bat ACE2 proteins we examined indicates that SARS-CoV-2 receptor usage likely shifted during zoonotic transmission from bats into people, possibly in an intermediate reservoir. Comparison of SARS-CoV-2 receptor usage to the related coronaviruses SARS-CoV and RaTG13 identified distinct tropisms, with the 2 human viruses being more closely aligned. Finally, using bioinformatics, structural data, and targeted mutagenesis, we identified amino acid residues within the Spike–ACE2 interface, which may have played a pivotal role in the emergence of SARS-CoV-2 in humans. The apparently broad tropism of SARS-CoV-2 at the point of viral entry confirms the potential risk of infection to a wide range of companion animals, livestock, and wildlife.

A study using a combination of surrogate entry assays and live virus suggests that SARS-CoV-2 may have a broad host-range, revealing that the virus''s spike protein can use a broad range of host ACE2 receptors to enter cells and that the sequence of this protein might have changed during the zoonotic jump into humans.  相似文献   
986.
987.
Catabolite repression by glucose of the biosynthesis of alpha amylase and amyloglucosidase by Aspergillus niger CFTRI 1105 was studied in a solid state fermentation (SSF) and in submerged fermentation (SMF) systems and the results were compared. The addition of glucose did not enhance the production of alpha-amylase and amyloglucosidase in an earlier fermentation system. However, a drastic reduction in alpha-amylase production was observed in submerged fermentation by the addition of 5·0 mg ml−1 glucose and of amyloglucosidase production by 10 mg ml−1 glucose. Glucose concentrations above 50 mg ml−1 completely suppressed the production of both enzymes in the initial hours. In contrast, in the SSF system the repression was negligible, even when the glucose level was raised to 150 mg g−1 wheat bran for both alpha and amyloglucosidase synthesis.  相似文献   
988.
989.
990.
Following binding to cognate ligand, estrogen receptor (ER) β interacts with specific responsive elements of the target genes and recruits a host of nuclear proteins for hormone dependent gene regulation. However, it is poorly known which proteins interact with ER β in mouse brain and whether their interaction and expression change with age. In this report, we have used his-tag mouse ER β for interaction with nuclear proteins of cerebral cortex of young (6 ± 1 weeks), adult (25 ± 2 weeks), and old (70 ± 5 weeks) female mice. We have identified estrogen receptor-associated protein (ERAP) 140 as one of the interacting proteins and studied its interaction by pull down immunoblotting, far-Western blotting and immunoprecipitation, and expression by western blotting. The data show that ERAP 140 interacts with ER β and its interaction decreases but its expression increases with age in mouse cerebral cortex, suggesting its role in estrogen-mediated brain functions during aging.  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