全文获取类型
收费全文 | 102篇 |
免费 | 1篇 |
专业分类
教育 | 43篇 |
科学研究 | 37篇 |
体育 | 9篇 |
综合类 | 1篇 |
信息传播 | 13篇 |
出版年
2023年 | 1篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2015年 | 1篇 |
2014年 | 2篇 |
2013年 | 1篇 |
2012年 | 7篇 |
2011年 | 16篇 |
2010年 | 9篇 |
2009年 | 11篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 8篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 3篇 |
1997年 | 1篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 3篇 |
1984年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有103条查询结果,搜索用时 46 毫秒
31.
Copper accumulation and intracellular distribution in Elsholtzia splendens, a native Chinese Cu-tolerant and accumulating plant species, was investigated by transmission electron microscope (TEM) and gradient centrifugation techniques.Copper concentrations in roots, stems and leaves of E. splendens increased with increasing Cu levels in solution. After exposure to 500 μmol/L Cu for 8 d, about 1000 mg/kg Cu were accumulated in the stem and 250 mg/kg Cu in the leaf of E. splendens. At 50μmol/L Cu, no significant toxicity was observed in the chloroplast and mitochondrion within its leaf cells, but separation appeared at the cytoplasm and the cell wall within the root cells. At >250 μmol/L Cu, both root and leaf organelles in E. splendens were damaged heavily by excessive Cu in vivo. Copper subcellular localization in the plant leaf after 8 days' exposure to 500 μmol/L Cu using gradient centrifugation techniques was found to be decreased in the order: chloroplast>cell wall>soluble fraction>other organelles. The plant root cell wall was found to be the site of highest Cu localization. Increase of Cu exposure time from 8 d to 16d, increased slightly Cu concentration in cell wall fraction in roots and leaves, while that in the chloroplast fraction decreased in leaves of the plants grown in both 0.25 μmol/L and 500 μmol/L Cu. TEM confirmed that much more Cu localized in cell walls of E. splendens roots and leaves, but also more Cu localized in E. splendens' chloroplast when the plant is exposed to Cu levels>250μmol/L, as compared to those in the plant grown in 0.25 μmol/L Cu. Copper treatment at levels>250 μmol/L caused pronounced damage in the leaf chloroplast and root organelles. Copper localization in cell walls and chloroplasts could mainly account for the high detoxification of Cu in E. splendens. 相似文献
32.
OBJECTIVE: The aim of this study is to identify the distinct developmental experiences associated with child sexual abuse and rape. METHOD: For 269 sexual offenders (137 rapists and 132 child sexual abusers), developmental experiences were recorded from a behavioral checklist, a parental-bonding survey, and a sexual history questionnaire. Offender classification was obtained from official records and verified through polygraph examinations. RESULTS: Compared to rapists, child sexual abusers reported more frequent experiences of child sexual abuse (73%), early exposure to pornography (65% before age 10), an earlier onset of masturbation (60% before age 11), and sexual activities with animals (38%). In contrast to child sexual abusers, rapists reported more frequent experiences of physical abuse (68%), parental violence (78%), emotional abuse (70%), and cruelty to animals (68%). Both child sexual abusers and rapists (>93%) reported frequent exposure to violent media during their childhood. Most offenders (94%) described having insecure parental attachment bonds; 76% of rapists reported avoidant parental attachments and 62% of child sexual abusers reported anxious parental attachments. CONCLUSIONS: Findings from this study support the role of specific developmental experiences as etiological factors in differential sexual offending. Child sexual abusers' developmental histories were characterized by heightened sexuality; whereas rapists' childhood histories were more indicative of violence. These findings have implications for the treatment of sexual abusers and the prevention of sexual abuse. PRACTICE IMPLICATIONS: This study's findings suggest that sexual offenders have been socialized to satisfy human needs of intimacy and sexuality through maladaptive means, which implies that a risk management approach may not be sufficient treatment. Although risk models teach offenders skills to avoid high-risk situations, they fail to address the maladaptive strategies that they may have developed for satisfying needs. Instead, the focus of treatment should be to equip offenders with the knowledge, skills, and opportunities to achieve these needs in an acceptable manner. Thus, this model will provide these individuals with the opportunity to live a healthy life without sexual offending. 相似文献
33.
35.
Eldredge JD Morley SK Hendrix IC Carr RD Bengtson J 《Medical reference services quarterly》2012,31(1):34-44
Every major health profession now provides competency statements for preparing new members for their respective professions. These competency statements normally include expectations for training health professions students in library/informatics skills. For purposes of this article, searches were conducted using various sources to produce a comprehensive 32-page Compendium that inventories library/informatics-related competency statements. This compendium should aid readers in integrating their library/informatics skills training into various health professions education curricula. 相似文献
36.
OBJECTIVES: To examine the relationship between sexual abuse and academic achievement in an adolescent inpatient psychiatric population. Individual factors expected to influence this relationship were measured to explore the way they each interacted with sexual abuse and its relationship to academic achievement. METHOD: Eighty-one adolescent psychiatric inpatients participated in the study (aged 12--18 years: M=16.0). Participants were administered tests of academic achievement (dependent variable) and intelligence, and completed a number of self-report measures of their experience of different types of maltreatment, their perception of the parenting they received, socio-economic status, substance abuse, and psychopathology. RESULTS: Hierarchical regression analysis revealed that intelligence was the main predictor of academic achievement (uniquely explaining 26% of the variance). A number of interaction effects were also significant indicating that intelligence, substance abuse, internalizing behavior problems, externalizing behavior problems all influenced the relationship between sexual abuse and academic achievement. DISCUSSION: Examining the impact of sexual abuse is complex because it is typically an experience embedded in a range of other risk factors, such as poverty, family dysfunction, and other types of maltreatment. This study demonstrated coexistence between sexual abuse and a number of other variables, including other maltreatment types and parental overprotection, underscoring the requirement for complex models of research that more accurately reflect the experience of abused children. 相似文献
38.
39.
40.
本文介绍了美国华裔科学家潘卓华与卡尔 ? 戴瑟罗斯和爱德华 ? 博伊登之间关于光遗传学发明人的著名争议,由此剖析了其中折射出的学术期刊在审稿时的“误差判断”、学术从业者的“投稿策略”、以及学术成果的“保密”和“营销”手段等问题,进而提出学术界应当尽量祛除隐藏在众多学术争议背后的利益根源,回归传统的默顿规范。 相似文献