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   1011篇
  免费   107篇
  2021年   8篇
  2020年   7篇
  2019年   11篇
  2018年   10篇
  2017年   12篇
  2016年   11篇
  2015年   29篇
  2014年   31篇
  2013年   37篇
  2012年   39篇
  2011年   47篇
  2010年   30篇
  2009年   39篇
  2008年   52篇
  2007年   47篇
  2006年   35篇
  2005年   42篇
  2004年   49篇
  2003年   32篇
  2002年   33篇
  2001年   30篇
  2000年   34篇
  1999年   26篇
  1998年   13篇
  1997年   15篇
  1996年   16篇
  1995年   11篇
  1994年   14篇
  1993年   10篇
  1992年   18篇
  1991年   18篇
  1990年   26篇
  1989年   28篇
  1988年   16篇
  1987年   20篇
  1986年   23篇
  1985年   29篇
  1984年   17篇
  1983年   13篇
  1982年   9篇
  1981年   9篇
  1980年   8篇
  1979年   8篇
  1978年   11篇
  1977年   11篇
  1975年   9篇
  1973年   7篇
  1971年   9篇
  1967年   5篇
  1960年   8篇
排序方式: 共有1118条查询结果,搜索用时 31 毫秒
11.
OBJECTIVE--To compare the efficacy of home based care with standard hospital care in treating serious mental illness. DESIGN--Randomised controlled trial. SETTING--South Southwark, London. PATIENTS--189 patients aged 18-64 living in catchment area. 92 were randomised to home based care (daily living programme) and 97 to standard hospital care. At three months'' follow up 68 home care and 60 hospital patients were evaluated. MAIN OUTCOME MEASURES--Use of hospital beds, psychiatric diagnosis, social functioning, patients'' and relatives'' satisfaction, and activity of daily living programme staff. RESULTS--Home care reduced hospital stay by 80% (median stay six days in home care group, 53 days in hospital group) and did not increase the number of admissions compared with hospital care. On clinical and social outcome there was a non-significant trend in favour of home care, but both groups showed big improvements. On the global adjustment scale home care patients improved by 26.8 points and the hospital group by 21.6 points (difference 5.2; 95% confidence interval -1.5 to 12). Other rating scales showed similar trends. Home care patients required a wide range of support in areas such as housing, finance, and work. Only three patients dropped out from the programme. CONCLUSIONS--Home based care may offer some slight advantages over hospital based care for patients with serious mental illness and their relatives. The care is intensive, but the low drop out rate suggests appreciation. Changes to traditional training for mental health workers are required.  相似文献   
12.
13.
14.
15.
16.
17.
18.
Bacterial ribosome biogenesis is poorly understood especially in terms of the role of ribosomal RNA (rRNA) maturation in vivo. A major problem in addressing these questions are asynchronous biogenesis, a large population of mature particles and the lack of techniques to isolated in vivo formed ribosome biogenesis intermediates. Our group has taken multiple approaches to allow study of ribosome biogenesis in Escherichia coli. We have used genetic manipulation to discover that for specific biogenesis factors, there is a delicate balance that is necessary for viability. Additionally, we have pioneered an affinity purification approach to allow for isolation of in vivo formed intermediates. Data will be present on our findings for the role of rRNA maturation in biogenesis, subsequent ribosome function, and cell viability. Our findings may result in identification of novel targets for antimicrobial development.  相似文献   
19.
Species richness gradients are ubiquitous in nature, but the mechanisms that generate and maintain these patterns at macroecological scales remain unresolved. We use a new approach that focuses on overlapping geographical ranges of species to reveal that Indo-Pacific corals are assembled within 11 distinct faunal provinces. Province limits are characterized by co-occurrence of multiple species range boundaries. Unexpectedly, these faunal breaks are poorly predicted by contemporary environmental conditions and the present-day distribution of habitat. Instead, faunal breaks show striking concordance with geological features (tectonic plates and mantle plume tracks). The depth range over which a species occurs, its larval development rate and genus age are important determinants of the likelihood that species will straddle faunal breaks. Our findings indicate that historical processes, habitat heterogeneity and species colonization ability account for more of the present-day biogeographical patterns of corals than explanations based on the contemporary distribution of reefs or environmental conditions.  相似文献   
20.
The defensive skin secretions of amphibians are a rich resource for the discovery of novel, bioactive peptides. Here we report the identification of a novel vascular smooth muscle-relaxing peptide, named vasorelaxin, from the skin secretion of the Chinese piebald odorous frog, Odorrana schmackeri. Vasorelaxin consists of 20 amino acid residues, SRVVKCSGFRPGSPDSREFC, with a disulfide-bridge between Cys-6 and Cys-20. The structure of its biosynthetic precursor was deduced from cloned skin cDNA and consists of 67 amino acid residues encoding a single copy of vasorelaxin (vasorelaxin, accession number: HE860494). Synthetic vasorelaxin caused a profound relaxation of rat arterial smooth muscle with an EC50 of 6.76 nM.  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