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   3606篇
  免费   174篇
  国内免费   11篇
  2023年   72篇
  2022年   43篇
  2021年   87篇
  2020年   80篇
  2019年   65篇
  2018年   149篇
  2017年   122篇
  2016年   162篇
  2015年   101篇
  2014年   155篇
  2013年   286篇
  2012年   232篇
  2011年   270篇
  2010年   167篇
  2009年   115篇
  2008年   174篇
  2007年   182篇
  2006年   165篇
  2005年   172篇
  2004年   190篇
  2003年   204篇
  2002年   136篇
  2001年   85篇
  2000年   97篇
  1999年   63篇
  1998年   15篇
  1997年   18篇
  1996年   9篇
  1995年   8篇
  1994年   7篇
  1993年   6篇
  1992年   8篇
  1991年   9篇
  1990年   5篇
  1988年   12篇
  1987年   7篇
  1986年   5篇
  1985年   6篇
  1984年   12篇
  1983年   7篇
  1982年   6篇
  1981年   5篇
  1980年   5篇
  1978年   5篇
  1976年   4篇
  1975年   10篇
  1974年   6篇
  1973年   6篇
  1969年   4篇
  1966年   4篇
排序方式: 共有3791条查询结果,搜索用时 15 毫秒
1.
2.
Allopatric isolation in glacial refugia has caused differentiation and speciation in many taxa globally. In this study, we investigated the nuclear and mitochondrial genetic differentiation of the long fingered bat, Myotis capaccinii during the ice ages in south-eastern Europe and Anatolia. The mitochondrial DNA (mtDNA) analyses indicated a suture zone similar to those recorded in other animal species, including bats, suggesting the association of more than one refugium with the region. Contrary to most of the other species where a suture zone was seen in Anatolia, for M. capaccinii the geographical location of the genetic break was in south-eastern Europe. This mitochondrial differentiation was not reflected in the nuclear microsatellites, however, suggesting that the lack of contact during the ice ages did not result in reproductive isolation. Hence taxonomically, the two mitochondrial clades cannot be treated as separate species.  相似文献   
3.
This study seeks to explore whether neuroticism, agreeableness, and conscientiousness moderate the influence of relationship conflict experienced in groups on changes in group members'' evaluative cognitions related to teamwork quality (teamwork-related mental models). Data from 216 students, nested in 48 groups were analyzed using a multilevel modeling approach. Our results show that the experience of relationship conflict leads to a negative shift from the pre-task to the post-task teamwork-related mental models. Moreover, the results indicate that conscientiousness buffered the negative association between relationship conflict and the change in teamwork-related mental models. Our results did not support the hypothesized moderating effect of agreeableness and show that the detrimental effect of relationship conflict on the shift in teamwork-related mental models is accentuated for group members scoring low rather than high on neuroticism. These findings open new research venues for exploring the association between personality, coping styles and change in teamwork-related mental models.  相似文献   
4.
5.
6.
7.
Cerebrohepatorenal malformation is a rare familial disorder characterized by typical renal lesions combined with Dandy-Walker malformation, and congenital hepatic fibrosis. In this case report, a male premie with the diagnosis of cerebrorenal syndrome or so called Goldston syndrome is presented. Besides the rarity of this syndrome, this case is the second reported patient diagnosed prenatally.  相似文献   
8.
Torture.     
  相似文献   
9.
The antiinflammatory activity of three hydrosoluble aryldimethyltriazenes has been examined on the carrageenin induced edema in guinea pig. The administration of equitoxic dosages of p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK) and p-(3,3-dimethyl-1-triazeno)sulfonic acid sodium salt (DM-SO3Na) 1 h after carrageenin application, causes 4 h later a similar and statistically significant reduction of paw swelling by about 40% whereas, p-alanylphenyl-3,3-dimethyl-1-triazeno (DM-ALA(OH)) is inactive. Of the two active compounds, DM-COOK displays interesting properties, being rapidly active and causing a peak of inhibition higher than that caused by DM-SO3Na. The antiinflammatory activity of DM-COOK is comparable with that caused by 5 mg/kg indomethacin and 200 mg/kg phenylbutazone. However, DM-COOK, unlike indomethacin, causes an inhibition of leukocyte migration into the peritoneal cavity induced by casein treatment, thus indicating a different mechanism of action. This effect needs clarification and seems not to be correlated to cytotoxicity of the drug for migrating white blood cells, as evidenced by "in vitro' examination.  相似文献   
10.
Any neural network aimed at the coding sensory events must contain computational properties which generally allow the organism to reconstruct the input signals with some degree of accuracy-else the association between stimulus and response would, at best, be uncertain. In this paper we investigate the problem of reconstructing external input signals to neural networks when the activity profiles of only some of its member cells are known. The evolution and activities of such cells are defined by an earlier formulation of one of us (Ouztöreli 1979) and, here, we restrict our application to local curcuits within the vertebrate retina. Solutions to this inverse coding problem are presented for specific network equations and examplified with 1, 3, and 5 neuron cases.This work was partially supported by the Natural Sciences and Engineering Research Council of Canada under Grant A-4345 to M.N.O. and grant A-4395 to T.M.C. through the University of Alberta  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