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   494篇
  免费   36篇
  2024年   2篇
  2023年   4篇
  2022年   5篇
  2021年   9篇
  2020年   24篇
  2019年   13篇
  2018年   14篇
  2017年   40篇
  2016年   19篇
  2015年   18篇
  2014年   14篇
  2013年   56篇
  2012年   33篇
  2011年   20篇
  2010年   9篇
  2009年   16篇
  2008年   26篇
  2007年   26篇
  2006年   11篇
  2005年   17篇
  2004年   15篇
  2003年   6篇
  2002年   14篇
  2001年   6篇
  2000年   5篇
  1999年   8篇
  1998年   9篇
  1997年   6篇
  1996年   4篇
  1995年   6篇
  1994年   4篇
  1993年   3篇
  1992年   5篇
  1991年   5篇
  1990年   5篇
  1989年   5篇
  1988年   5篇
  1987年   3篇
  1984年   2篇
  1983年   6篇
  1982年   5篇
  1981年   10篇
  1980年   2篇
  1978年   3篇
  1976年   3篇
  1975年   1篇
  1973年   1篇
  1971年   2篇
  1965年   1篇
  1963年   1篇
排序方式: 共有530条查询结果,搜索用时 15 毫秒
501.
502.
503.
504.
ABSTRACT: In the United States, suicide has traditionally been considered a White elderly phenomenon. Suicide rates have been increasing for Nonwhites in recent years, but it is not clear how this may have affected the age distribution, particularly for specific Nonwhite groups. An investigation of official 1976 suicide statistics among minority elderly revealed that suicide rates are also highest among the old for Chinese-, Japanese- and Filipino-Americans. Among Blacks and Native Americans, however, suicide rates are extremely low for the aged. Explanations for these findings are suggested and the need for a long-term study is indicated.  相似文献   
505.
Abstract

Variable practice promotes a higher level of motor learning than constant practice. The glutamate receptors, n-methyl-d-aspartate (NMDA) and alfa-amino-3-hydroxy-5-methyl-4-isoxazolepropionic (AMPA), have been associated with the changes in motor cortex that occur throughout the process of motor learning. Considering that, it is possible that variable practice is more associated with the NMDA and AMPA receptors than constant practice. This study aimed ao investigating the association between the glutamate receptors, NMDA and AMPA, and constant and variable practice schedules. Seventy-eight male mice practiced the rotarod task in a constant or variable scheduling, in two consecutive days (acquisition phase). Learning tests were performed 24?h and 10?days after the end of the acquisition phase. Variable practice was more associated with the NMDA receptor and had a greater AMPA receptor expression than constant practice. The results suggest that the benefits of variable practice are result of both the greater dependency on the NMDA receptor and the greater AMPA receptor expression.  相似文献   
506.
ABSTRACT: Suicide rates vary greatly by sex and race but the methods employed by these groups and changes in those methods have been studied neither closely nor systematically across time. In the present study annual official national statistics for specific methods of suicide by sex and racial group from 1923 to 1978 were examined. During this time period shifts were found among groups in the proportions of various suicide methods employed, most notably for women and Asian-Americans. Generally, firearm use increased among nearly all ethnic/racial-sex groups while the use of poisons declined. Although women continue to be more likely than men to kill themselves with solid and liquid poisons, in very recent years firearms have become a more common method. Among Japanese - and Chinese-Americans of both sexes the most frequently employed method has been hanging. Although this is still the case, the proportions have declined over time while the use of firearms has increased. Explanations are offered for the noted changes in method choice with particular attention being given to acculturation and changing societal roles.  相似文献   
507.
508.
ABSTRACT

The oil-rich nation-states of the Arabian Peninsula are investing large sums in the development of an international sports industry for the region. In an effort to field its own national sports teams for this industry, Qatar, who will host the 2022 FIFA World Cup, has relied upon the practice of naturalizing foreign athletes. It is not a new practice, but Qatar’s wholesale use of the practice amounts to annexing its national sports teams and seems to miss the point of a national team. Certainly, the practice raises questions about the nature of a distinctively national sports team. As I take up some of these questions, my discussion leads to the larger question of international sport as a conversation on the differentiation of national identities. The practice of annexing national sports teams, therefore, raises questions both about nationalism and internationalism.  相似文献   
509.
510.
Psychonomic Bulletin & Review - In this review article, we analyze how grammatical gender is represented and processed in the bilingual mind. To that end, we review the data from 13 existing...  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