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   33645篇
  免费   1332篇
  国内免费   19篇
  2020年   347篇
  2019年   478篇
  2018年   648篇
  2017年   700篇
  2016年   658篇
  2015年   485篇
  2014年   566篇
  2013年   2727篇
  2012年   958篇
  2011年   1091篇
  2010年   707篇
  2009年   696篇
  2008年   970篇
  2007年   895篇
  2006年   829篇
  2005年   710篇
  2004年   680篇
  2003年   702篇
  2002年   637篇
  2001年   1220篇
  2000年   1191篇
  1999年   868篇
  1998年   382篇
  1997年   315篇
  1996年   322篇
  1995年   317篇
  1994年   325篇
  1992年   729篇
  1991年   703篇
  1990年   665篇
  1989年   619篇
  1988年   588篇
  1987年   587篇
  1986年   549篇
  1985年   615篇
  1984年   484篇
  1983年   372篇
  1979年   471篇
  1978年   351篇
  1977年   334篇
  1976年   310篇
  1975年   422篇
  1974年   418篇
  1973年   480篇
  1972年   386篇
  1971年   322篇
  1969年   327篇
  1968年   377篇
  1967年   333篇
  1966年   385篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
971.
Critical Flicker Fusion Thresholds (CFFTs) were measured in 644 elderly people identified from community-based general practice records, and the relationship of CFFT with age was investigated. The CFFT was measured using the method of limits with mean scores for three ascending (flicker/fusion) and three descending (fusion/flicker) presentations being recorded. The difference between the ascending and descending means was found to be significantly correlated with age (r=−0.131,P<0.001) and may reflect a reduced sensitivity of the Central Nervous System to suprathreshold flicker with increasing age. The results suggest that CFFT measurement has an important role to play in gerontological research as an objective measure of cognitive aspects of the ageing process.  相似文献   
972.
973.
Patterns of manual preference and the extent to which preference provided a benefit in performance (movement time) were evaluated in 7 young adult capuchin monkeys (Cebus apella). Directions of preference were inconsistent within individual animals across home-cage activities, unimanual, and bimanual experimental tasks. Preferences were more strongly expressed in the experimental tasks than in the home cage. A left bias in the population for prehension, predicted by recent theories, was not evident in any setting. Movement time was moderately negatively correlated with degree of preference within experimental tasks. The benefit to performance conferred by lateral preference was not dependent on whether the right or left hand was preferred. Lateralization of prehension appears to be a flexible process in these monkeys, which can result in quickly realized benefits in some conditions.  相似文献   
974.
The story of Joseph in the Qur'an has been approached by many non‐Muslim writers1 who were content to list which details of the biblical story have been missed out from the biblical story and which points have been added, maintaining that these had their origins in biblical or other Jewish sources. Our treatment here concentrates on the texts of the story in the Qur'an and the Old Testament, attempting to identify the differing functions and preoccupations of the two accounts in their respective contexts, to show how this difference affects the choice of material and the treatment given to it. This article concludes that the two versions should be approached by readers, Muslims and non‐Muslims, with this difference in mind in order to appreciate the message and the qualities of each.  相似文献   
975.
This study examines the factor structure of the Mobility Inventory for Agoraphobia and attempts to validate the inventory, using an Australian sample of agoraphobic patients, by comparison with other scales. One hundred twentyfour panic disorder with agoraphobia patients were studied. Factor analysis showed that a two-factor solution was the most suitable both when subjects were accompanied (accompanied condition) and when alone (alone condition). Factor I represented public, crowded, or social situations including department stores, supermarkets, restaurants, theaters, and panics and social gatherings. Factor II reflected enclosed or riding situations such as elevators, parking garages, enclosed spaces, and riding in subways or airplanes. These two factors accounted for 46.6% and 44.3% of the variance on the accompanied condition and the alone condition, respectively. The Mobility Inventory was significantly correlated with the Agoraphobia factor of the Fear Questionnaire and the Social Avoidance and Distress scale. These results indicated that the Mobility Inventory is a valid instrument to measure agoraphobic behavior.  相似文献   
976.
The right hand hemisphere of the brain is purported to be the seat of the perceptual, intuitive, synthetic, visual and non-rational activities. In it is believed to reside the creative ability. Evidence is presented which suggests that, by exercising specifically the right hand hemisphere using a series of carefully structured tasks, some aspects of creative behaviour can be enhanced. It follows that users of creativity training courses should not expect every aspect of creative behaviour to be enhanced by any given course.  相似文献   
977.
In this article the perspective shifts to the “upstream” end of the agricultural knowledge and information system (AKIS). Because knowledge policy and strategic decision-making are not the prerogative of the public sector, organizations such as cooperative unions and multinational companies are included. After considering the influence of the changing environment on the nature of the AKIS, the role of knowledge management and policy in the emerging knowledge and information market is examined. Special attention is given to public and private R&D. The article then looks where information technology (IT) fits in and what considerations determine strategic investment in IT projects and sustained services. Some of the European experiences with this strategic investment are evaluated.  相似文献   
978.
979.
980.
Depression in some patients with spinal cord injuries may be clinically significant and, when present, should be treated to decrease morbidity including decreased physical functioning. Depression associated with spinal cord injury (SCI) may be misevaluated, due to (1) nonspecific multifactorial production of depression symptoms and (2) SCI-specific decrease in somatic sensory central nervous system input. The Somatic Suppression Hypothesis suggests that SCI patients have difficulty experiencing any intense emotion because of suppression of physiological arousal. In addition, cognitive processes that may reduce depression in SCI patients include: (1) attribution of somatic symptoms of depression to medical (biological) causes, (2) realistic, positive expectations for physical improvement, and (3) the perception that the disability of the SCI is only minimally related to the patient’s self-care after complete evaluation. Health personnel should accept lack of depression in SCI, and should encourage positive realistic expectations of recovery.  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