全文获取类型
收费全文 | 786篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
教育 | 571篇 |
科学研究 | 47篇 |
各国文化 | 7篇 |
体育 | 96篇 |
文化理论 | 3篇 |
信息传播 | 72篇 |
出版年
2021年 | 4篇 |
2020年 | 11篇 |
2019年 | 22篇 |
2018年 | 30篇 |
2017年 | 27篇 |
2016年 | 26篇 |
2015年 | 18篇 |
2014年 | 21篇 |
2013年 | 165篇 |
2012年 | 20篇 |
2011年 | 26篇 |
2010年 | 18篇 |
2009年 | 12篇 |
2008年 | 22篇 |
2007年 | 18篇 |
2006年 | 18篇 |
2005年 | 13篇 |
2004年 | 12篇 |
2003年 | 12篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 8篇 |
1997年 | 9篇 |
1996年 | 11篇 |
1995年 | 13篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 15篇 |
1991年 | 17篇 |
1990年 | 13篇 |
1989年 | 12篇 |
1988年 | 12篇 |
1987年 | 7篇 |
1985年 | 11篇 |
1984年 | 7篇 |
1983年 | 7篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 8篇 |
1978年 | 4篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1973年 | 6篇 |
1972年 | 6篇 |
1971年 | 6篇 |
1921年 | 3篇 |
1828年 | 3篇 |
排序方式: 共有796条查询结果,搜索用时 15 毫秒
781.
782.
Although historical changes in scientific ideas sometimes display striking similarities with students’ conceptual progressions, some scholars have cautioned that such similarities lack meaningful commonalities. In the history of evolution, while Darwin and his contemporaries often used natural selection to explain evolutionary trait gain or increase, they struggled to use it to convincingly account for cases of trait loss or decrease. This study examines Darwin’s evolutionary writings about trait gain and loss in the Origin of Species (On the origin of species by means of natural selection, or the preservation of favoured races in the struggle for life. D. Appleton, New York, 1859) and compares them to written evolutionary explanations for trait gain and loss in a large (n > 500), cross-cultural and cross-sectional sample (novices and experts from the USA and Korea). Findings indicate that significantly more students and experts applied natural selection to cases of trait gain, but like Darwin and his contemporaries, they more often applied ‘use and disuse’ and ‘inheritance of acquired characteristics’ to episodes of trait loss. Although the parallelism between Darwin’s difficulties and students’ struggles with trait loss are striking, significant differences also characterize explanatory model structure. Overall, however, students and scientists struggles to explain trait loss—which is a very common phenomenon in the history of life—appear to transcend time, place, and level of biological expertise. The significance of these findings for evolution education are discussed; in particular, the situated nature of biological reasoning, and the important role that the history of science can play in understanding cognitive constraints on science learning. 相似文献
783.
Klaus Libertus Kelly A. Sheperd Samuel W. Ross Rebecca J. Landa 《Child development》2014,85(6):2218-2231
Atypical motor behaviors are common among children with autism spectrum disorders (ASD). However, little is known about onset and functional implications of differences in early motor development among infants later diagnosed with ASD. Two prospective experiments were conducted to investigate motor skills among 6‐month‐olds at increased risk (high risk) for ASD (N1 = 129; N2 = 46). Infants were assessed using the Mullen Scales of Early Learning (MSEL) and during toy play. Across both experiments, high‐risk infants exhibited less mature object manipulation in a highly structured (MSEL) context and reduced grasping activity in an unstructured (free‐play) context than infants with no family history of ASD. Longitudinal assessments suggest that between 6 and 10 months, grasping activity increases in high‐risk infants. 相似文献
784.
Universities aim to provide services that are not only beneficial to students but also efficient relative to possible alternative services. Using opportunity cost, this study considers staff and student perceptions of the usefulness and valuation of web-based lecture technology (WBLT). It reveals that a quarter of students did not use WBLT while many staff members thought WBLT had a negative impact on their face-to-face teaching. Further, over a third of students sampled said they would not be affected if WBLT were not made available and many staff members felt constrained by WBLT technology. Some staff members spent a lot of time preparing WBLT while others eschewed the technology altogether. Nevertheless, a relatively small number of students place enormous value on WBLT, as do some staff, even if only simple audio of lectures are provided. The academic policy implications of this study suggest that university provision of WBLT could take into account the opportunity cost of WBLT use as a valuation-basis, possibly recovering costs through extra fees. This would allow for improved decision-making by university administrators and facilitate a move towards a useful measurement basis of WBLT. A wider academic policy implication is to consider whether all universities should produce and deliver WBLT at all and to what extent it should encourage staff to develop enhanced WBLT. Provision of sophisticated WBLT or any other service for students bears an opportunity cost in terms of less preparation by staff for face-to-face lessons or other effective teaching or research. 相似文献
785.
Ramesh Raghavan Derek S. Brown Benjamin T. Allaire Lauren D. Garfield Raven E. Ross Lonnie R. Snowden 《Child abuse & neglect》2014
This study quantifies racial/ethnic differences in Medicaid expenditures on psychotropic drugs among a national sample of children with suspected maltreatment. We linked 4,445 child participants in the National Survey of Child and Adolescent Well-Being (NSCAW) – consisting of children investigated for suspected abuse and neglect – to their Medicaid claims obtained from 36 states. We used propensity score matching to construct a comparison group of children without known child welfare involvement, and estimated two-part generalized linear models to examine differences in annual psychotropic drug expenditures per child between children of different races/ethnicities. When compared to a matched sample of children, African American and Latino children incur $292 and $144 less expenditures on psychotropic drugs, respectively, than white children. Among NSCAW children alone, African American children display $614 less spending on psychotropic drugs when compared to white children. Racial/ethnic differences in expenditures on psychotropic drugs occur among all children on Medicaid, but the differences are especially pronounced among African American children in contact with the child welfare system. These findings demonstrate that policymakers will need to pay special attention to the needs of children of color as Medicaid expansions proceed nationwide. 相似文献
786.
787.
Mandy J. Hill Camden J. Hallmark Marlene McNeese Nike Blue Michael W. Ross 《Sex education》2014,14(2):128-143
The goal of this paper was to determine the effectiveness of the HIP HOP for HIV Awareness intervention, an innovative model utilising an exchange of an HIV test for a hip hop concert ticket, in a metropolitan city among African American youth and young adults. A subset of intervention participants participated in standardised testing, sex education and pre/post test administration. Data were analysed to identify changes in knowledge and attitudes with respect to HIV and sexually transmitted infections pre/post the educational session. An analysis of knowledge revealed variance in the pre- and post-assessment findings among participants receiving the intervention. Level of education and gender significantly influenced the variance in knowledge discerned from the pre- and post-assessment among participants. Two three-level significant interactions emerged from the analysis of variance: knowledge, education and gender; and knowledge, education and race/ethnicity. Programme findings suggest that an increase in knowledge and improved self-perceptions related to attitudes are the result of a brief, HIV-focused community-based intervention among young adults. 相似文献
788.
Spencer JP Clearfield M Corbetta D Ulrich B Buchanan P Schöner G 《Child development》2006,77(6):1521-1538
This paper is in memory of Esther Thelen, who passed away while President of the Society for Research in Child Development. A survey of Esther Thelen's career reveals a trajectory from early work on simple movements like stepping, to the study of goal-directed reaching, to work on the embodiment of cognition, and, ultimately, to a grand theory of development--dynamic systems theory. Four central concepts emerged during her career: (1) a new emphasis on time; (2) the proposal that behavior is softly assembled from the interaction of multiple subsystems; (3) the embodiment of perception, action, and cognition; and (4) a new respect for individuality. Esther Thelen communicated these ideas to scientists and practitioners alike, so the ultimate benefactors of her work were children. 相似文献
789.
Ross W. Bellaby 《Ethics and Information Technology》2018,20(3):189-204
Anonymising technologies are cyber-tools that protect people from online surveillance, hiding who they are, what information they have stored and what websites they are looking at. Whether it is anonymising online activity through ‘TOR’ and its onion routing, 256-bit encryption on communications sent or smart phone auto-deletes, the user’s identity and activity is protected from the watchful eyes of the intelligence community. This represents a clear challenge to intelligence actors as it prevents them access to information that many would argue plays a vital part in locating and preventing threats from being realised. Moreover, such technology offers more than ordinary information protections as it erects ‘warrant-proof’ spaces, technological black boxes that no matter what some authority might deem as being legitimately searchable is protected to the extent that there are very limited or non-existent means of forcing oneself in. However, it will be argued here that not only is using such anonymising technology and its extra layer of protection people’s right, but that it is ethically mandatory. That is, due to the en masse surveillance—from both governments and corporations—coupled with people’s limited awareness and ability to comprehend such data collections, anonymising technology should be built into the fabric of cyberspace to provide a minimal set of protections over people’s information, and in doing so force the intelligence community to develop more targeted forms of data collection. 相似文献
790.
Anna K. Wood Ross K. Galloway Christine Sinclair Judy Hardy 《Teaching in Higher Education》2018,23(7):818-834
In this paper we develop knowledge of the discourse that takes place between teacher and students in two large undergraduate classes which use a flipped, active learning approach. In flipped classes students encounter the content through pre-class resources, freeing up class time for more active engagement with the material. This results in increased opportunities for teacher-student interactions which may be beneficial for learning. Our aim here is to explore the nature and purposes of these dialogues. Two case studies from introductory physics classes at the University of Edinburgh are analysed through a sociocultural perspective. Three main purposes of dialogues are observed: (1) Involving students in sense-making, (2) Guided expert modelling and (3) Wonderment questions. We found that the dialogues predominantly use a triadic Initiation, Response, Feedback (IRF) format and are authoritative in nature, but work together to create an interactive learning environment that can be described as ‘ideologically dialogic’ 相似文献