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   449篇
  免费   43篇
  2022年   2篇
  2021年   11篇
  2020年   5篇
  2019年   7篇
  2018年   6篇
  2017年   9篇
  2016年   10篇
  2015年   27篇
  2014年   23篇
  2013年   19篇
  2012年   45篇
  2011年   36篇
  2010年   21篇
  2009年   15篇
  2008年   30篇
  2007年   29篇
  2006年   16篇
  2005年   18篇
  2004年   37篇
  2003年   23篇
  2002年   18篇
  2001年   7篇
  2000年   3篇
  1998年   8篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1993年   4篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   1篇
  1986年   3篇
  1982年   4篇
  1981年   3篇
  1980年   3篇
  1977年   1篇
  1976年   4篇
  1975年   1篇
  1974年   6篇
  1973年   5篇
  1972年   3篇
  1971年   3篇
  1970年   3篇
  1969年   1篇
  1968年   1篇
  1967年   1篇
  1965年   1篇
排序方式: 共有492条查询结果,搜索用时 0 毫秒
491.
The main objective of this study was to evaluate the role of the concentration of solid air-suspended particles (SSP) in the incidence of mental disorders. The study is based on 1,871 cases, registered in the Beer-Sheva Mental Health Center (BS-MHC) at Ben-Gurion University (Israel) during a 16-month period from 2001 to 2002; 1,445 persons were hospitalized due to exacerbation of schizophrenia (ICD-10: F20–F29) and 426 after committing a suicide attempt using a variety of means as coded in the ICD-10 (ICD-10: X60-X84). Pearson and Spearman test correlations were used; the statistical significance was tested at p?<?0.1. A significant correlation between variations of SSP number concentration (N C ) during eastern desert wind during early morning hours and number of suicide attempts, N SU , was found (ρ?>?0.3, p?<?0.05), whereas correlation between N C and N SU during western air streams (sea breeze) was not observed (p?>?0.2). A trend towards positive correlation (ρ?>?0.2, p?<?0.1) between the N C and number of persons with exacerbation of schizophrenia as manifested in psychotic attack (N PS ) in periods with dominant eastern winds (4–9 am, local time) has been observed, while in the afternoon and evening hours (1–8 pm local time) with dominant western winds, N C and N PS are not correlated (p?>?0.1). Obviously, concentration of SSP is not the one and only parameter of air pollution state determining meteorological–biological impact, involving incidence of mental disorders, although its role can scarcely be overstated. However, since it is one of the simplest measured parameters, it could be widely used and helpful in the daily struggle for human life comfort in semi-arid areas as well as urban and industrial surroundings, where air pollution reaches crucial values. This study may permit determination of the limits for different external factors, which do not overcome threshold values (without provoking avalanche situations), to single out the group of people at increased risk (with according degree of statistic probability), whose reactions to the weather violations can involve the outbreak of frustration points and prevent or alleviate detrimental mental effects.  相似文献   
492.
While the last century brought an exquisite understanding of the molecular basis of life, very little is known about the detailed chemical mechanisms that afforded the emergence of life on early earth. There is a broad agreement that the problem lies in the realm of chemistry, and likely resides in the formation and mutual interactions of carbon-based molecules in aqueous medium. Yet, present-day experimental approaches can only capture the synthesis and behavior of a few molecule types at a time. On the other hand, experimental simulations of prebiotic syntheses, as well as chemical analyses of carbonaceous meteorites, suggest that the early prebiotic hydrosphere contained many thousands of different compounds. The present paper explores the idea that given the limitations of test-tube approaches with regards to such a 'random chemistry' scenario, an alternative mode of analysis should be pursued. It is argued that as computational tools for the reconstruction of molecular interactions improve rapidly, it may soon become possible to perform adequate computer-based simulations of prebiotic evolution. We thus propose to launch a computational origin of life endeavor (http://ool.weizmann.ac.il/CORE), involving computer simulations of realistic complex prebiotic chemical networks. In the present paper we provide specific examples, based on a novel algorithmic approach, which constitutes a hybrid of molecular dynamics and stochastic chemistry. As one potential solution for the immense hardware requirements dictated by this approach, we have begun to implement an idle CPU harvesting scheme, under the title ool@home.  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