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   6467篇
  免费   63篇
  国内免费   1篇
  2020年   23篇
  2019年   26篇
  2018年   165篇
  2017年   139篇
  2016年   229篇
  2015年   135篇
  2014年   72篇
  2013年   283篇
  2012年   331篇
  2011年   336篇
  2010年   73篇
  2009年   86篇
  2008年   110篇
  2007年   118篇
  2006年   110篇
  2005年   1384篇
  2004年   733篇
  2003年   514篇
  2002年   204篇
  2001年   60篇
  2000年   42篇
  1999年   51篇
  1998年   38篇
  1997年   32篇
  1996年   34篇
  1995年   31篇
  1994年   42篇
  1993年   34篇
  1992年   49篇
  1991年   58篇
  1990年   87篇
  1989年   74篇
  1988年   55篇
  1987年   59篇
  1986年   54篇
  1985年   49篇
  1984年   51篇
  1983年   39篇
  1982年   29篇
  1981年   24篇
  1979年   41篇
  1978年   33篇
  1976年   28篇
  1975年   43篇
  1974年   37篇
  1973年   41篇
  1972年   31篇
  1971年   31篇
  1968年   20篇
  1967年   22篇
排序方式: 共有6531条查询结果,搜索用时 15 毫秒
181.
Aged rats with extensive prior training on the radial maze retain the capacity for accurate spatial working memory (WM) for at least 3 months without practice. To investigate the temporal limits of this influence of prior experience we compared the reacquisition of spatial WM by a group of experienced 21.5-month-old rats to the original acquisition by naive 3-month-old rats. The aged rats had received 225 radial maze tests between 3 and 11 months of age. Despite 10 months without practice the old rats rapidly reacquired critical performance. Their reacquisition was markedly superior to original learning by the young rats, even when delays as long as 5 h were imposed between the rats' fourth and fifth choices during the daily tests in the eight-arm maze. Additional tests showed that neither young nor old rats employed a response strategy to maintain accurate spatial WM performance. Experience clearly confers long-lived protection against the otherwise deleterious effects of aging on spatial WM, but the mechanism by which this influence arises is unknown.  相似文献   
182.
183.
Anxiety, nausea and vomiting before, during and after chemotherapy administration were studied in 50 cancer patients. In addition, patient responses to the Autonomic Perception Questionnaire (APQ) and their relation to the anxiety, nausea and vomiting scores was studied. Anticipatory anxiety occurred in 66% and anticipatory nausea in 40% of the patients; 14% showed anticipatory vomiting. The number of patients reporting anxiety decreased to 38% after chemotherapy, whereas nausea and vomiting increased to 47 and 49%, respectively. APQ scores correlated significantly with anxiety and nausea reports during all time periods, but not with the frequency of vomiting.  相似文献   
184.
185.
186.
The present study examined the association of cardiac autonomic task-induced reactivity and recovery to preclinical atherosclerosis. Thirty-three men and 33 women aged 24-39 years participated in the ongoing epidemiological Cardiovascular Risk in Young Finns study. The authors measured heart rate (HR), respiratory sinus arrhythmia (RSA), and preejection period (PEP) during the mental arithmetic and speech tasks in 1999. Carotid atherosclerosis was assessed by measuring the thickness of the common carotid artery intima-media complex (IMT) with ultrasound in 2001. Higher HR, RSA, and PEP reactivity were associated with lower IMT values even after adjusting for cardiovascular risk factors (lipid levels, obesity, and blood pressure). In addition, better HR recovery after the mental arithmetic task was associated with lower IMT values, and this association persisted after all adjustments. Thus, higher task-induced cardiac autonomic reactivity and better HR recovery were related to less preclinical atherosclerosis. The authors concluded that cardiac pattern of reactivity and quick recovery may be associated with better cardiovascular health, and therefore all reactivity occurring in challenging situations should not automatically be considered as potentially pathological.  相似文献   
187.
A TASTE FOR HUME     
Patricia de  Martelaere 《Ratio》1989,2(2):122-137
  相似文献   
188.
189.
190.
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