全文获取类型
收费全文 | 3379篇 |
免费 | 447篇 |
国内免费 | 607篇 |
专业分类
4433篇 |
出版年
2024年 | 10篇 |
2023年 | 105篇 |
2022年 | 118篇 |
2021年 | 150篇 |
2020年 | 209篇 |
2019年 | 195篇 |
2018年 | 171篇 |
2017年 | 196篇 |
2016年 | 203篇 |
2015年 | 172篇 |
2014年 | 195篇 |
2013年 | 562篇 |
2012年 | 146篇 |
2011年 | 171篇 |
2010年 | 131篇 |
2009年 | 164篇 |
2008年 | 182篇 |
2007年 | 155篇 |
2006年 | 157篇 |
2005年 | 134篇 |
2004年 | 136篇 |
2003年 | 113篇 |
2002年 | 89篇 |
2001年 | 70篇 |
2000年 | 65篇 |
1999年 | 47篇 |
1998年 | 31篇 |
1997年 | 44篇 |
1996年 | 39篇 |
1995年 | 33篇 |
1994年 | 21篇 |
1993年 | 27篇 |
1992年 | 24篇 |
1991年 | 12篇 |
1990年 | 16篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 15篇 |
1986年 | 9篇 |
1985年 | 10篇 |
1984年 | 8篇 |
1983年 | 12篇 |
1982年 | 8篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 7篇 |
1978年 | 14篇 |
1977年 | 5篇 |
1976年 | 8篇 |
1975年 | 6篇 |
排序方式: 共有4433条查询结果,搜索用时 15 毫秒
951.
近年来,生物库成为了人们关注的焦点,因为生物库已经成为了生物制药和药学研究领域新的必备基础和来源。生物库所承载的历史使命是极具挑战性的,甚至有些令人望而却步:它既要将现有生物样本库转化成基因学研究的新的研究工具,又要建立大规模人群生物库。建立或维护生物库不仅仅是一项简单的收集工作,而是要通过生物库管理来赋予其特定的知识价值,这种知识价值可以产生相应的医疗健康意义或某种经济价值。生物库的成败与否,生物库创造价值的能力,取决于管理体系的确立和有序模式的建立,其建立可以为分类提供策略,并最终建立一个互动的网络体系,这个互动网络体系呈现在一系列不同的领域中:科学/技术领域,医药/卫生领域,产业化经济领域,法律道德和社会政治领域。 相似文献
952.
由于人类赖以存在的水资源、空气和土壤等受到严重污染,直接或间接地引发人类某些疾病的产生甚至爆发,对人类健康和生存发展构成了巨大的威胁。对此,一方面,需要对医学模式进行重新审视。生物心理社会医学模式的局限性逐渐突显,生物心理社会生态医学模式最终将成为引领未来医学发展的基本模式。另一方面,需要以人类健康为导向加强生态文明建设:转变思想观念,树立生态中心主义观;依靠科学技术,积极发展生态经济;完善国家健康发展战略,制定环境与健康行动计划;建设健康城市,营造生态优美的人居环境。 相似文献
953.
954.
Nathan A. Heflick Jamie L. Goldenberg Elisa Puvia 《Journal of experimental social psychology》2011,47(3):572-581
Most literally, objectification refers to perceiving a person as an object, and consequently, less than fully human. Research on perceptions of humanness and the stereotype content model suggests that humanness is linked to perceptions of warmth, morality and competence. Merging these insights with objectification theory, we hypothesized that focusing on a woman's, but not a man's, appearance should induce objectification, and thus reduce perceptions of these characteristics. In three studies, females, but not males, were perceived as less competent (Studies 2 and 3) and less warm and moral (Studies 1, 2 and 3) when participants were instructed to focus on their appearance. These findings support our position and help rule out stereotype activation as an alternative explanation to dehumanization. Further, they generalized to targets of different races, familiarity, physical attractiveness and occupational status. Implications for gender inequity and the perpetuation of objectification of women are discussed. 相似文献
955.
Kees-Jan Kan 《Intelligence》2011,39(5):292
On the one hand, the factors Gf and Gc in the Cattell-Horn-Carroll (CHC) model of intelligence are hypothesized to represent individual differences in unique psychological or biological capacities. On the other hand, they are interpreted as representing the theoretical variables fluid and crystallized intelligence in investment theory. With respect to Gc, this leads to a theoretical conflict because in investment theory crystallized intelligence is not a capacity but purely a statistical entity. We contend that if CHC factor Gc represents a capacity, it cannot represent crystallized intelligence, and if Gc represents crystallized intelligence, it does not represent a capacity. In addition, from our discussion of Gc, we conclude that in investment theory the factors Gf and g represent one and the same capacity. In support of our theoretical conclusions, we implemented the CHC model in a confirmatory factor analysis of a HCA (Human Cognitive Abilities project) data set. As expected, Gf and g were statistically indistinguishable. Gc was effectively absent, because it was statistically equivalent to verbal comprehension. Factors Gc and g could be removed from the model without any reduction in model fit. We argue that in the CHC taxonomy the factors Gc and g are redundant as explanatory variables. 相似文献
956.
957.
Hallucinations have been found to be associated with various types of source memory failure in both schizophrenia patients and hallucination-prone healthy individuals. We investigated the associations of clinical and non-clinical hallucinations with source memory errors in a visual memory task that involved the remembering of picture presentation context. 59 schizophrenia patients and 61 healthy individuals took part in the study. Pictures were presented either at different locations or in association with different visual stimuli. The participants were required afterwards to recognize the target pictures among distractors, and then to remember their spatial location or the visual stimulus that was associated with them. Liberal response bias in picture recognition was associated with hallucination proneness and auditory-verbal hallucinations in subsamples of participants with significant non-clinical or clinical hallucinations. After controlling for overall memory performance, failure to remember the spatial location of the pictures was associated with visual hallucinations in male patients; failure to remember the associated visual stimulus was related to auditory-verbal hallucinations in female patients and to hallucination proneness in healthy women. The findings suggest that both clinical and non-clinical hallucinations are associated with loss of contextual information relative to the acquisition of events. 相似文献
958.
双因子模型假设测验考察一个一般因子和多个组因子,符合很多教育和心理测验的因素结构。“维度缩减”方法将参数估计中多维积分计算化简为多个迭代二维积分,是双因子模型的重要特征。本文针对考察多级评分项目的计算机化自适应测验,首先推导双因子等级反应模型下Fisher信息量的计算,然后推导“维度缩减”方法在项目选择方法中的应用,最后在低、中、高双因子模式题库中比较D-优化方法、后验加权Fisher信息D优化方法(PDO)、后验加权Kullback-Leibler方法(PKL)、连续熵(CEM)和互信息(MI)方法在能力估计的相关、均方根误差、绝对值偏差和欧氏距离的表现。模拟研究表明:(1)双因子模式越强,即一般因子和组因子在项目上的区分度的差异越小,一般因子估计精度降低,组因子估计精度增加,整体能力的估计精度提高;(2)相同实验条件下,连续熵方法的测量精度最高,PKL方法的能力估计精度最低,其它方法的测量精度没有显著差异。 相似文献
959.
随着心理与教育测量研究的发展和科技的进步,计算机化(大规模)测验逐渐受到人们的关注。为探究在计算机化多维测验中如何利用作答时间数据来辅助评估多维潜在能力,以及为我国义务教育阶段教育质量监测提供数据分析方法上的理论支持。本研究以2012年和2015年国际学生能力评估(PISA)计算机化数学测验数据为例,提出了一种可同时利用作答时间和作答精度数据的联合作答与时间的多维Rasch模型。根据新模型对PISA数据的分析结果,表明引入作答时间数据,不仅有助于提高模型参数的估计精度,还有助于数据分析者利用被试的作答时间信息来做进一步的决策和干预(e.g., 对异常作答行为或预备知识的诊断)。 相似文献
960.
John T. Mitchell Nathan A. Kimbrel Natalie E. Hundt Amanda R. Cobb Rosemery O. Nelson-Gray Christopher M. Lootens 《欧洲人格杂志》2007,21(7):869-887
Reinforcement Sensitivity Theory (RST) and the Five-Factor Model (FFM) are two prominent personality accounts that have emerged from different backgrounds. Although the two accounts are applied to similar research topics, there is limited empirical work examining the correspondence between them. The current study explored the relationship between RST-based personality traits and the FFM domains and facets in an undergraduate sample (n = 668). Regression analyses indicated that Sensitivity to Punishment (SP) was positively associated with Neuroticism and Agreeableness, and negatively associated with Extraversion, Openness, and Conscientiousness. In contrast, Sensitivity to Reward (SR) was positively associated with Extraversion and Neuroticism, and negatively associated with Agreeableness and Conscientiousness. Exploratory analyses at the facet level specified the relationship between SP, SR, and each domain. A factor analysis was also conducted to explore the higher-order factor structure of RST and the FFM domains. Three factors emerged, which we labelled SP, Stability-Impulsivity, and Sensation Seeking. Taken together, these findings suggest that there is substantial overlap between these two accounts of personality. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献