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   235篇
  免费   14篇
  国内免费   16篇
  2024年   3篇
  2023年   1篇
  2022年   4篇
  2021年   2篇
  2020年   5篇
  2019年   14篇
  2018年   9篇
  2017年   8篇
  2016年   10篇
  2015年   5篇
  2014年   13篇
  2013年   42篇
  2012年   6篇
  2011年   10篇
  2010年   11篇
  2009年   11篇
  2008年   15篇
  2007年   22篇
  2006年   13篇
  2005年   13篇
  2004年   10篇
  2003年   4篇
  2002年   6篇
  2001年   6篇
  2000年   4篇
  1999年   4篇
  1998年   2篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1988年   1篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1978年   1篇
  1975年   1篇
排序方式: 共有265条查询结果,搜索用时 15 毫秒
1.
This study examined how preschool inattention-hyperactivity is related to elementary school reading achievement. Prereading skills were hypothesized to be a link between them. This link was explored using longitudinal data on 105 low-socioeconomic-status (SES) children's inattentive-hyperactive behavior and prereading skills in Head Start and in kindergarten and their inattentive-hyperactive behavior and reading skills in first grade. A model of this relationship was tested using structural equation modeling. The results failed to show a significant path between inattention-hyperactivity and prereading skills at both the Head Start and kindergarten levels. A significant path was found between first grade inattention-hyperactivity and reading skills, confirming that the strong relationship between inattention-hyperactivity and poor reading achievement commonly found in children from other SES levels was also significant in this low-SES sample. Strong relationships were found between pre-reading skills and reading skills, as well as among hyperactivity levels at the three grades. The issue of the direction of the path of influence between attention-behavior and reading achievement is addressed briefly; however, the results indicate that further longitudinal work is necessary to resolve this issue.  相似文献   
2.
The relationship between closed head injury and performance on neuropsychological (NP) tests was investigated in a group of intravenous drug users (IVDUs). Subjects with repeated head traumas involving loss of consciousness (LOC) performed worse than both a control group without LOC and reference group with only a single episode of LOC. There were no significant differences between the last two groups. Performance on tests of memory, attention, and motor performance was significantly worse in the group with repeated head injury. The average time since the last episode of LOC was more than 11 years. We conclude from these findings that a single episode of LOC does not result in significant cognitive impairment in this population. Two or more episodes, however, are more likely to produce chronic cognitive impairment.  相似文献   
3.
This study investigated the prevalence of traumatic brain injury (TBI) in an inpatient psychiatric population. We hypothesized increased prevalence of TBI relative to the general population due to a variety of risk factors observed in psychiatric patients. One hundred (mean age = 34) psychiatric inpatients completed the revised Head Injury Questionnaire. Chart review of 17 subjects reporting injuries established whether injuries were documented in medical records. Sixty-eight percent of this psychiatric population reported one or more injuries in which they were unconscious or dazed. This number is higher than the prevalence in the general population. Injuries were generally of mild to moderate severity; multiple injuries were common. Chart review of 17 subjects reporting TBI indicated that histories of TBI had not been noted in the medical record. Finally, 63% of TBI subjects reported that their injury predated the onset of their psychiatric symptoms. These results suggest a possible role of TBI in psychiatric symptomatology and have implications for psychiatric treatment in this population.  相似文献   
4.
5.
This study was designed to investigate the predictive efficiency of the primary and secondary summary codes of Holland's Self-Directed Search for Educational and Vocational Planning (SDS) in terms of expressed career choice 4 years later. In 1974, 126 voiationally undecided high school seniors were given the SDS, followed by a revision of Trow's Vocational Choice Inventory (VCI) in which they were asked to express a career choice or a state of indecision. In 1978, this same group was mailed a posttest VCI; the responses of 84 subjects were then analyzed. The subjects' expressed career choices on both the 1974 and 1978 VCI were compared to the primary and secondary summary codes on the SDS which they had taken in 1974. Inspection of the responses indicated that 21.4% of the subjects had made career choices predicted by their primary summary codes and 51.2% had made vocational choices found among their secondary summary codes. Only 27.4% chose a career area not predicted by their 1974 SDS results. The results of this study appear to lend support to the validity of using the SDS summary codes to predict eventual career decisions.  相似文献   
6.
Abstract

This research examines how the direction and intensity of employee’s positive and negative affect at work combine within different profiles, and the relations between these profiles and theoretically-relevant predictors (psychological need satisfaction and supervisor autonomy support) and outcomes (work-family conflict, absenteeism, and turnover intentions). A total sample of 491 firefighters completed our measures initially, and 139 of those completed the same measures again four months later, allowing us to examine the stability of these affect profiles over time. Latent profile analyses and latent transition analyses revealed five identical profiles across the two measurements occasions: (1) Low Negative Affect Facilitators; (2) Moderately Low Positive Affect Incapacitators; (3) High Positive Affect Facilitators; (4) Very Low Positive Affect Incapacitators; and (5) Normative. Membership into Profiles 3, 4, and 5 was very stable over time. In contrast, Profiles 1 and 2 were associated with a highly unstable membership over time. The highest levels of work-family conflict, absenteeism, and turnover intentions were associated with the Very Low Positive Affect Incapacitators. In contrast, the lowest levels of turnover intentions were associated with the Low Negative Affect Facilitators and High Positive Affect Facilitators.  相似文献   
7.
Key ethical issues arise in association with the conduct of stem cell research by research institutions in the United States. These ethical issues, summarized in detail, receive no adequate translation into federal laws or regulations, also described in this article. U.S. Federal policy takes a passive approach to these ethical issues, translating them simply into limitations on taxpayer funding, and foregoes scientific and ethical leadership while protecting intellectual property interests through a laissez faire approach to stem cell patents and licenses. Those patents and licenses, far from being scientifically and ethically neutral in effect, virtually prohibit commercially sponsored research that could otherwise be a realistic alternative to the federal funding gap. The lack of federal funding and related data-sharing principles, combined with the effect of U.S. patent policy, the lack of key agency guidance, and the proliferation of divergent state laws arising from the lack of Federal leadership, significantly impede ethical stem cell research in the United States, without coherently supporting any consensus ethical vision. Research institutions must themselves implement steps, described in the article, to integrate addressing ethical review with the many legal compliance issues U.S. federal and state laws create. The opinions expressed in this article are the author’s own, and are not necessarily the opinions of others, including Children’s Hospital Boston. Portions of earlier versions of this article were previously published by the American Bar Association and the New York State Bar Association.  相似文献   
8.
9.
The immunotoxin 192-saporin, infused intracerebroventricularly into rats, destroys cholinergic neurons in the basal forebrain nuclei. Doses required for complete cholinergic loss also kill some Purkinje cells. The immunotoxin OX7-saporin, when infused intraventricularly into rats, destroys Purkinje cells in a pattern similar to that produced by 192-saporin, without affecting cholinergic neurons. Thus, we used OX7-saporin to distinguish behavioral effects of 192-saporin due to cerebellar damage versus those due to cholinergic cell loss. Three doses of 192-saporin (1.6, 2.6, and 3.3 micrograms/rat) were chosen along with a dose of OX7-saporin (2.0 micrograms/rat) that produced Purkinje loss equivalent to the two highest doses of 192-saporin. Groups of Fischer-344 rats were trained in the multiple choice reaction time task and retested with more complex tasks after lesioning. They were also tested in the water maze, passive avoidance, acoustic startle, and open field. The OX7-saporin group exhibited changes in many tests suggesting hypermotility and sensory deficits. The 192-saporin groups differed from the OX7-saporin group when they displayed deficits in multiple choice reaction time tasks in which novel challenges were introduced, including sessions with a noise distractor, shortened and lengthened intertrial intervals, and use of nine instead of five sources of light stimulus. The 192-saporin groups showed no impairment in the other tasks. The cholinergic basal forebrain lesion may mask some of the effects of cerebellar damage up to a threshold after which effects of Purkinje cell loss predominate when 192-saporin is administered intraventricularly.  相似文献   
10.
The ability to learn the direction of causal relations is critical for understanding and acting in the world. We investigated how children learn causal directionality in situations in which the states of variables are temporally dependent (i.e., autocorrelated). In Experiment 1, children learned about causal direction by comparing the states of one variable before versus after an intervention on another variable. In Experiment 2, children reliably inferred causal directionality merely from observing how two variables change over time; they interpreted Y changing without a change in X as evidence that Y does not influence X. Both of these strategies make sense if one believes the variables to be temporally dependent. We discuss the implications of these results for interpreting previous findings. More broadly, given that many real‐world environments are characterized by temporal dependency, these results suggest strategies that children may use to learn the causal structure of their environments.  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