全文获取类型
收费全文 | 1166篇 |
免费 | 32篇 |
国内免费 | 2篇 |
专业分类
教育 | 872篇 |
科学研究 | 85篇 |
各国文化 | 10篇 |
体育 | 107篇 |
文化理论 | 9篇 |
信息传播 | 117篇 |
出版年
2022年 | 10篇 |
2021年 | 17篇 |
2020年 | 25篇 |
2019年 | 49篇 |
2018年 | 55篇 |
2017年 | 52篇 |
2016年 | 38篇 |
2015年 | 20篇 |
2014年 | 25篇 |
2013年 | 265篇 |
2012年 | 39篇 |
2011年 | 33篇 |
2010年 | 18篇 |
2009年 | 19篇 |
2008年 | 23篇 |
2007年 | 21篇 |
2006年 | 25篇 |
2005年 | 20篇 |
2004年 | 25篇 |
2003年 | 20篇 |
2002年 | 18篇 |
2001年 | 15篇 |
2000年 | 16篇 |
1999年 | 14篇 |
1998年 | 15篇 |
1997年 | 13篇 |
1996年 | 19篇 |
1995年 | 18篇 |
1994年 | 10篇 |
1993年 | 16篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 16篇 |
1989年 | 11篇 |
1988年 | 12篇 |
1986年 | 14篇 |
1985年 | 11篇 |
1984年 | 13篇 |
1983年 | 10篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 5篇 |
1979年 | 7篇 |
1977年 | 9篇 |
1976年 | 9篇 |
1975年 | 5篇 |
1974年 | 8篇 |
1973年 | 5篇 |
1969年 | 5篇 |
1890年 | 7篇 |
排序方式: 共有1200条查询结果,搜索用时 78 毫秒
101.
Meghan L. Critchley Daniel J. Davis Michaela M. Keener Jacob S. Layer Margaret A. Wilson Qin Zhu 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(4):421-437
ABSTRACT The purpose was to quantify the effects of mid-flight whole-body and trunk rotation on knee mechanics in a double-leg landing. Eighteen male and 20 female participants completed a jump-landing-jump task in five conditions: no rotation, testing leg ipsilateral or contralateral (WBRC) to the whole-body rotation direction, and testing leg ipsilateral (TRI) or contralateral to the trunk rotation direction. The WBRC and TRI conditions demonstrated decreased knee flexion and increased knee abduction angles at initial contact (2.6 > Cohen’s dz > 0.3) and increased peak vertical ground reaction forces and knee adduction moments during the 100 ms after landing (1.7 > Cohen’s dz > 0.3). The TRI condition also showed the greatest knee internal rotation angles at initial contact and peak knee abduction and internal rotation angles and peak knee extension moments during the 100 ms after landing (2.0 > Cohen’s dz > 0.5). Whole-body rotation increased contralateral knee loading because of its primary role in decelerating medial-lateral velocities. Trunk rotation resulted in the greatest knee loading for the ipsilateral knee due to weight shifting and mechanical coupling between the trunk and lower extremities. These findings may help understand altered trunk motion in anterior cruciate ligament injuries. 相似文献
102.
Kym Joanne Price Brett Ashley Gordon Stephen Richard Bird Amanda Clare Benson 《Journal of sports sciences》2020,38(9):970-984
ABSTRACTInterval exercise training is increasingly recommended to improve health and fitness; however, it is not known if cardiovascular risk is different from continuous exercise protocols. This systematic review with meta-analyses assessed the effect of a single bout of interval exercise on cardiovascular responses that indicate risk of cardiac fibrillation and infarction compared to continuous exercise. Electronic databases Medline, CINAHL, Embase, Scopus and Cochrane were searched. Key inclusion criteria were: (1) intervals of the same intensity and duration followed by a recovery period and (2) reporting at least one of blood pressure, heart rate variability, arterial stiffness or function. Cochrane Risk of Bias tool and GRADE approach were used. Meta-analyses found that systolic blood pressure responses to interval exercise did not differ from responses to continuous exercise immediately (MD 8 mmHg [95% CI ?32, 47], p = 0.71) or at 60 min following exercise (MD 0 mmHg [95% CI ?2, 1], p = 0.79). However, reductions in diastolic blood pressure and flow-mediated dilation with interval exercise were observed 10–15 min post-exercise. The available evidence indicates that interval exercise does not convey higher cardiovascular risk than continuous exercise. Further investigation is required to establish the safety of interval exercise for clinical populations. 相似文献
103.
Eric R. Muoz Jaclyn B. Caccese Brittany E. Wilson Kyle T. Shuler Fernando V. Santos Carolina T. Cabn John J. Jeka Dianne Langford Matthew B. Hudson 《运动与健康科学(英文)》2021,10(2):122
BackgroundConsidering the potential cumulative effects of repetitive head impact (HI) exposure, we need sensitive biomarkers to track short- and long-term effects. Circulating small extracellular vesicles (sEVs) (<200 nm) traffic biological molecules throughout the body and may have diagnostic value as biomarkers for disease. The purpose of this study was to identify the microRNA (miRNA) profile in circulating sEVs derived from human plasma following repetitive HI exposure.MethodsHealthy adult (aged 18–35 years) soccer players were randomly assigned to one of 3 groups: the HI group performed 10 standing headers, the leg impact group performed 10 soccer ball trapping maneuvers over 10 min, and the control group did not participate in any soccer drills. Plasma was collected before testing and 24 h afterward, and sEVs were isolated and characterized via nanoparticle tracking analysis. Next-generation sequencing was utilized to identify candidate miRNAs isolated from sEVs, and candidate microRNAs were analyzed via quantitative polymerase chain reaction. In silico target prediction was performed using TargetScan (Version 7.0; targetscan.org) and miRWalk (http://mirwalk.umm.uni-heidelberg.de/) programs, and target validation was performed using luciferase reporter vectors with a miR-7844-5p mimic in human embryonic kidney (HEK) 293T/17 cells.ResultsPlasma sEV concentration and size were not affected across time and group following repetitive HI exposure. After 24 h, the HI read count from next-generation sequencing showed a 4-fold or greater increase in miR-92b-5p, miR-423-5p, and miR-24-3p and a 3-fold or greater decrease in miR-7844-5p, miR-144-5p, miR-221-5p, and miR-22-3p. Analysis of quantitative polymerase chain reaction revealed that leg impact did not alter the candidate miRNA levels. To our knowledge, miR-7844-5p is a previously unknown miRNA. We identified 8 miR-7844-5p mRNA targets: protein phosphatase 1 regulatory inhibitor subunit 1B (PPP1R1B), LIM and senescent cell antigen-like domains 1 (LIMS1), autophagy-related 12 (ATG12), microtubule-associated protein 1 light chain 3 beta (MAP1LC3B), integrin subunit alpha-1 (ITGA1), mitogen-activated protein kinase 1 (MAPK1), glycogen synthase kinase 3β (GSK3β), and mitogen-activated protein kinase 8 (MAPK8).ConclusionCollectively, these data indicate repetitive HI exposure alters plasma sEV miRNA content, but not sEV size or number. Furthermore, for the first time we demonstrate that previously unknown miR-7844-5p targets mRNAs known to be involved in mitochondrial apoptosis, autophagy regulation, mood disorders, and neurodegenerative disease. 相似文献
104.
Patti Wilson 《Psychology in the schools》2004,41(3):301-311
This research study evaluated the efficacy of the Bracken Basic Concept Scale‐Revised (BBCS‐R; Bracken, 1998) and the Bracken Concept Development Program (BCDP; Bracken, 1986a) in a test‐teach‐test paradigm with students from a Head Start program. Prior to the intervention, 54 children were administered the BBCS‐R and were divided into three groups, two of which received basic concept instruction. Once the intervention was completed, the children were reassessed with the BBCS‐R. Posttest scores were calculated for each BBCS‐R subtest and the Total Test and School Readiness Composites after controlling for the pretest scores. A MANOVA and sequential ANOVAs were conducted and proved a significantly higher performance of the two intervention groups compared to the control group. Effect sizes for five of the six BBCS‐R subtests were classified as large, with the sixth (Time/Sequence) classified as medium. Discriminant function coefficients found that the Texture/Material subtest contributed the most to the detection of differences between the groups. However, no significant difference between the two intervention groups was found. © 2004 Wiley Periodicals, Inc. Psychol Schs 41: 301–311, 2004. 相似文献
105.
M P Wilson 《Bulletin of the Medical Library Association》1968,56(1):46-48
The National Library of Medicine Extramural Program in administering the Medical Library Assistance Act of 1965 has developed the following specific program objectives: provide financial assistance for improving biomedical libraries; encourage and assist the establishment and functioning of a responsive national biomedical information network by strengthening present biomedical libraries and their interlibrary relationships; and assure that the biomedical library network is linked to related science information systems. The ultimate goal is to develop the role of the library as a full learning resource center for education, research, and service. The regional library program aims to augment present capability of existing medical libraries so that information can be made available more extensively and more rapidly. Comprehensive and thorough advanced planning is a basic element in the development of regional medical libraries. 相似文献
106.
107.
108.
ABSTRACTThe Deep Dive into KBART preconference workshop provided a comprehensive overview of the National Information Standards Organization Knowledge Bases and Related Tools (KBART) Phase II Recommended Practice (http://www.niso.org/publications/rp/rp-9–2014/). The workshop was divided into four sections. The first provided an overview of the background, purpose, and value of KBART to all members of the information supply chain. The next section focused on the basic guidelines for effective exchange of metadata with knowledgebases, including method of exchange, data format, file naming conventions, and frequency of exchange. The remaining two sections of the workshop addressed the correct use of KBART data fields, first in relation to serials and then to monographs. Through classroom instruction, interactive quizzes, and hands-on exercises, the workshop provided in-depth coverage of all KBART data elements, with special focus on many of the most frequently asked questions about the recommended practice. 相似文献
109.
110.
International Journal of Science and Mathematics Education - In the rush to implement STEM programmes in economically disadvantaged school districts, there is a pressing need to develop a stronger... 相似文献