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   720篇
  免费   74篇
  2023年   6篇
  2022年   14篇
  2021年   9篇
  2020年   19篇
  2019年   29篇
  2018年   46篇
  2017年   39篇
  2016年   41篇
  2015年   31篇
  2014年   40篇
  2013年   85篇
  2012年   60篇
  2011年   46篇
  2010年   38篇
  2009年   31篇
  2008年   45篇
  2007年   45篇
  2006年   31篇
  2005年   34篇
  2004年   23篇
  2003年   13篇
  2002年   18篇
  2001年   8篇
  2000年   2篇
  1999年   5篇
  1998年   5篇
  1997年   2篇
  1996年   4篇
  1995年   2篇
  1994年   4篇
  1993年   2篇
  1992年   2篇
  1989年   1篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1981年   2篇
  1979年   1篇
  1974年   1篇
  1972年   2篇
  1969年   2篇
  1966年   1篇
排序方式: 共有794条查询结果,搜索用时 250 毫秒
161.
Merck suppressed data on harmful effects of its drug Vioxx, and Guidant suppressed data on electrical flaws in one of its heart-defibrillator models. Both cases reveal how financial conflicts of interest can skew biomedical research. Such conflicts also occur in electric-utility-related research. Attempting to show that increased atomic energy can help address climate change, some industry advocates claim nuclear power is an inexpensive way to generate low-carbon electricity. Surveying 30 recent nuclear analyses, this paper shows that industry-funded studies appear to fall into conflicts of interest and to illegitimately trim cost data in several main ways. They exclude costs of full-liability insurance, underestimate interest rates and construction times by using “overnight” costs, and overestimate load factors and reactor lifetimes. If these trimmed costs are included, nuclear-generated electricity can be shown roughly 6 times more expensive than most studies claim. After answering four objections, the paper concludes that, although there may be reasons to use reactors to address climate change, economics does not appear to be one of them.  相似文献   
162.
Relations of toddlers' observed negative affect in high- and low-threat contexts to maternal perceptions of their toddlers' internalizing problems and to mothers' responses to emotions (RTE) for fear and sadness were examined. Child-driven, parent-driven, and reciprocal transactional models across 1 year were directly compared. Two-year-old toddlers (N = 106) participated in lab-based activities to elicit distress, and their negative affect was coded. Mothers completed measures of their child's internalizing behaviors and their responses to their toddler's fear and sadness at ages 2 and 3. At age 2, only negative affect in low-threat contexts was associated with greater internalizing problems. Mothers' punishing and minimizing RTE at age 2 predicted an increase in internalizing problems across 1 year. Age 2 internalizing problems predicted an increase in mother's use of supportive RTE over time. Results highlight the importance of considering the context of toddlers' negative affective displays and supported a reciprocal conceptualization of toddlers' internalizing behaviors and mothers' RTE.  相似文献   
163.
This study's aims were to describe the spirituality of depressed elderly psychiatric inpatients and to examine associations among spirituality, depression, and quality of life (QOL). Forty-five persons participated. Most reported frequent, stable spiritual practices and experiencing spiritual comfort and guidance. Some reported spiritual distress and changes in spirituality. During hospitalization, participants demonstrated increased spiritual well-being (SWB) and peacefulness, and reduced hopelessness, worthlessness, and guilt. Positive associations were found between SWB and QOL and negative associations between SWB and depression.  相似文献   
164.
This study examined if subcortical stroke was associated with impaired facial emotion recognition. Furthermore, the lateralization of the impairment and the differential profiles of facial emotion recognition deficits with localized thalamic or basal ganglia damage were also studied. Thirty-eight patients with subcortical strokes and 19 matched normal controls volunteered to participate. The participants were individually presented with morphed photographs of facial emotion expressions over multiple trials. They were requested to classify each of these morphed photographs according to Ekman's six basic emotion categories. The findings indicated that the clinical participants had impaired facial emotion recognition, though no clear lateralization pattern of impairment was observed. The patients with localized thalamic damage performed significantly worse in recognizing sadness than the controls. Longitudinal studies on patients with subcortical brain damage should be conducted to examine how cognitive reorganization post-stroke would affect emotion recognition.  相似文献   
165.
In many languages, the production of noun phrases requires the selection of gender-marked elements like determiners or inflectional suffixes. There is a recent debate as to whether the selection of freestanding gender-marked elements, such as determiners, follows the same processing mechanisms as the selection of bound gender-marked morphemes, such as adjective suffixes. Most of the evidence on which this debate is based relates to the gender-congruency effect in picture-word interference experiments. In the present article, the authors address this issue with a pure picture-naming task, extending previous work in German (H. Schriefers, J. D. Jescheniak, & A. Hantsch, 2005). The results of the present study on noun phrase production in Dutch show that both types of gender-marked morphemes are selected via the same basic processing mechanisms.  相似文献   
166.
When participants are asked to make sensibility judgments on sentences that describe action toward the body (i.e., "Mark dealt the cards to you") or away from the body (i.e., "You dealt the cards to Mark"), they are faster to respond when the response requires an arm movement in the same direction as the action described by the sentence. This congruence effect is known as the Action–Sentence Compatibility Effect (ACE). This study reports 4 experiments that extend our understanding of the ACE by exploring how the time at which one prepares the motor response required for the sensibility judgment affects the magnitude of the ACE. Results show that the ACE arises only when participants have the opportunity to plan their motor response while they are processing the sentence.  相似文献   
167.
Sleep after learning aids memory recall   总被引:7,自引:0,他引:7       下载免费PDF全文
In recent years, the effect of sleep on memory consolidation has received considerable attention. In humans, these studies concentrated mainly on procedural types of memory, which are considered to be hippocampus-independent. Here, we show that sleep also has a persisting effect on hippocampus-dependent declarative memory. In two experiments, we examined high school students' ability to remember vocabulary. We show that declarative memory is enhanced when sleep follows within a few hours of learning, independent of time of day, and with equal amounts of interference during retention intervals. Sleep deprivation has a detrimental effect on memory, which was significant after a night of recovery sleep. Thus, fatigue accumulating during wake intervals could be ruled out as a confound.  相似文献   
168.
Clinical and some epidemiological data conflict concerning the likelihood of suicide attempt in individuals with panic disorder (PD). The purpose of this study was to illuminate the panic disorder-suicide attempt association in the National Comorbidity Survey (NCS; R. C. Kessler et al., 1994). Specifically, suicide attempt histories of those 5,872 respondents answering "yes" or "no" to the suicide attempt question were regressed against lifetime diagnostic histories. Lifetime PD history, in the presence of other disorders, was unrelated to elevated risk of suicide attempt and did not account for additional variance. PD respondents who had made a suicide attempt were characterized by Comorbidity. Epidemiological respondents with lifetime histories of PD alone are not at heightened risk for self-reported suicide attempt.  相似文献   
169.
This study evaluated behavioral skills training (BST), in a multiple baseline across subjects design, for teaching firearm safety skills to 6 6- and 7-year-old children. Similar to previous research with 4- and 5-year-olds, half of the children acquired the safety skills following BST and half acquired the skills following BST plus in situ training.  相似文献   
170.
This study examined the effectiveness of individual behavioral skills training in conjunction with in situ training in teaching 13 preschool children abduction prevention skills. Children's performance was measured during baseline, training, and at 2-week, 1-month, and 3-month follow-ups using in situ assessments in which abduction prevention skills were measured in naturalistic settings. Results revealed that all the children learned the skills and all the children available at the 2-week and 1-month follow-ups maintained the skills at criterion level. All but 3 children's criterion-level performances were maintained at the 3-month follow-up as well.  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