全文获取类型
收费全文 | 1937篇 |
免费 | 40篇 |
国内免费 | 3篇 |
专业分类
教育 | 1488篇 |
科学研究 | 93篇 |
各国文化 | 23篇 |
体育 | 182篇 |
文化理论 | 14篇 |
信息传播 | 180篇 |
出版年
2022年 | 9篇 |
2021年 | 23篇 |
2020年 | 46篇 |
2019年 | 64篇 |
2018年 | 84篇 |
2017年 | 110篇 |
2016年 | 91篇 |
2015年 | 69篇 |
2014年 | 56篇 |
2013年 | 430篇 |
2012年 | 63篇 |
2011年 | 60篇 |
2010年 | 51篇 |
2009年 | 57篇 |
2008年 | 48篇 |
2007年 | 51篇 |
2006年 | 42篇 |
2005年 | 31篇 |
2004年 | 40篇 |
2003年 | 17篇 |
2002年 | 34篇 |
2001年 | 21篇 |
2000年 | 30篇 |
1999年 | 15篇 |
1998年 | 19篇 |
1997年 | 27篇 |
1996年 | 28篇 |
1995年 | 31篇 |
1994年 | 32篇 |
1993年 | 24篇 |
1992年 | 14篇 |
1991年 | 9篇 |
1990年 | 20篇 |
1989年 | 18篇 |
1988年 | 20篇 |
1987年 | 8篇 |
1986年 | 16篇 |
1985年 | 6篇 |
1984年 | 13篇 |
1983年 | 16篇 |
1982年 | 10篇 |
1981年 | 14篇 |
1980年 | 13篇 |
1979年 | 11篇 |
1978年 | 15篇 |
1977年 | 6篇 |
1976年 | 8篇 |
1975年 | 8篇 |
1974年 | 8篇 |
1973年 | 6篇 |
排序方式: 共有1980条查询结果,搜索用时 15 毫秒
61.
62.
Helmer D Savoie I Green C Kazanjian A 《Bulletin of the Medical Library Association》2001,89(4):346-352
BACKGROUND: Cochrane-style systematic reviews increasingly require the participation of librarians. Guidelines on the appropriate search strategy to use for systematic reviews have been proposed. However, research evidence supporting these recommendations is limited. OBJECTIVE: This study investigates the effectiveness of various systematic search methods used to uncover randomized controlled trials (RCTs) for systematic reviews. Effectiveness is defined as the proportion of relevant material uncovered for the systematic review using extended systematic review search methods. The following extended systematic search methods are evaluated: searching subject-specific or specialized databases (including trial registries), hand searching, scanning reference lists, and communicating personally. METHODS: Two systematic review projects were prospectively monitored regarding the method used to identify items as well as the type of items retrieved. The proportion of RCTs identified by each systematic search method was calculated. RESULTS: The extended systematic search methods uncovered 29.2% of all items retrieved for the systematic reviews. The search of specialized databases was the most effective method, followed by scanning of reference lists, communicating personally, and hand searching. Although the number of items identified through hand searching was small, these unique items would otherwise have been missed. CONCLUSIONS: Extended systematic search methods are effective tools for uncovering material for the systematic review. The quality of the items uncovered has yet to be assessed and will be key in evaluating the value of the systematic search methods. 相似文献
63.
Interaction of wrestling shoe and competition surface: effects on coefficient of friction with implications for injury 总被引:1,自引:0,他引:1
Newton R Doan B Meese M Conroy B Black K Sebstianelli W Kramer W 《Sports biomechanics / International Society of Biomechanics in Sports》2002,1(2):157-166
The purpose of this study was to determine whether there is a significant difference in the co-efficient of friction (Fc) between old versus new wrestling shoes and mats and to investigate the effect of perspiration. Fc was measured by dragging a weighted shoe over a wrestling mat surface and measuring the vertical and horizontal forces produced. Three different shoe conditions were assessed over two mat types for both wet and dry conditions for a total of 12 conditions. To simulate the wet condition, saline solution was smeared over the surface of the mat. There was a significant effect of shoe, mat, and wet/dry conditions. In addition, significant interactions of shoe by mat, shoe by dry/wet, and mat by dry/wet were observed. Overall, Fc was 36% higher for the new wrestling mat compared to the old wrestling mat. Application of the saline solution reduced Fc by 14% compared to the dry condition. Comparison of the mean Fc for all three shoe types revealed the Fc for the older design shoe was 23% to 28% lower than the brand new shoe and the worn newer design, respectively. A high Fc, such as in the new mat/new shoe combination, has the potential to increase the risk of knee and ankle injuries by fixing the foot more securely to the ground. 相似文献
64.
Maraj BK 《Research quarterly for exercise and sport》2003,74(3):248-256
Two experiments explored perception and action for stair climbing, with manipulations to the stair dimensions. In Experiment 1, a custom-built apparatus manipulated the stair dimensions, while three groups of participants made perceptual judgments of climbability. The groups differed significantly for absolute leg length (p < .0001), but there was no significant difference between the groups when stair dimensions were calculated relative to leg length. The selected tread depths and riser heights reflected constant proportions of participants' leg length. Using the pitch angles formed as a composite metric, the results revealed that all groups selected 60 degrees as the limit for climbability. Experiment 2 scaled pitch angle systematically from 20 degrees to 80 degrees, and participants judged 65 degrees and beyond to be unclimbable. These results provided evidence that pitch angle might be used in perceptual judgments for stair climbability. 相似文献
65.
Comparison of oil and egg tempera paint systems using time-of-flight secondary ion mass spectrometry
Zachary E. Voras Kristin deGhetaldi Brian Baade Eric Gordon Glenn Gates Thomas P. Beebe 《文物保护研究》2016,61(4):222-235
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is quickly becoming a critical tool in the field of art conservation. This technique provides high-resolution spatial maps of both inorganic and organic components located within cross-sectional samples collected from works of art. With recent advances in surface analysis, ToF-SIMS can now be used to identify specific amino acids present in protein-containing materials as well as fatty acids in drying oils. For example, the detection of the ion fragment associated with the amino acid hydroxyproline can be used to confirm the use of animal glue in a paint sample. As an analytical technique, ToF-SIMS avoids the need for derivatization/silylation reagents, with no interference by the presence of pigments. Furthermore, the layered systems that are often encountered in historical paint samples remain intact throughout the analytical procedure. This allows for the co-localization of organic and inorganic species in specific layers (e.g. egg yolk paint atop a glue ground). Because of this ability to localize the analytical signal to approximately 6?µm or less, the mass spectral information can be used to produce mass-resolved and spatially-resolve images which can be correlated to previous studies of the same samples. In this study, ToF-SIMS was used to analyze a paint cross section obtained from a painting attributed to Raphael, and another from a painting by the Sienese artist Matteo di Giovanni. 相似文献
66.
ABSTRACTClass-related parenting cultures and ideologies have been of considerable interest to academics over the last two decades. Much of the research thus far has focused on exploring Annette Lareau's conceptualisations of ‘natural growth’ and ‘concerted cultivation’ and the implications for outcomes in relation to education. The focus of the present article is organised activities, which are a central but as yet relatively under-researched feature of middle-class parenting. The findings are based upon 73 semi-structured interviews with parents and children from 48 middle-class families living in and around a small city in northern England. The article reveals that initiating and facilitating children's organised activities is considered a central aspect of ‘good’ parenting in middle-class social networks. It is shown how this is a consequence of several developments within society over the past three decades or so, including the rising levels of maternal employment, the growing competitiveness of the labour market and the increasing concerns related to children's health and safety. It is argued that these developments have heightened middle-class parents’ predisposition to not only be involved with and invest in their children's leisure biographies, but to do so in a more deliberate, rigorous and rational manner. 相似文献
67.
A. D. C. Peterson Brian Holmes G. De Landsheere Helena W. F. Stellwag Oskar Anweiler J. O. J. Vanden Bossche Abraham Robinson F. I. Calvert H. H. Stern J. F. Willatt Sydney Taylor M. J. Langeveld M. A. Brimer T. N. Postlethwaite Alexandre Vexliard 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1964,10(1):106-126
68.
This investigation provides an extensive review of scientific, religious, and otherwise non-scientific factors that may influence student acceptance of biological evolution. We also measure the extent to which students' levels of acceptance changed following an educational experience designed to address an inclusive inventory of factors identified as potentially affecting student acceptance of evolution (n = 81, pre-test/post-test) n = 37, one-year longitudinal). Acceptance of evolution was measured using the Measure of Acceptance of the Theory of Evolution (MATE) instrument among participants enrolled in a secondary-level academic programme during the summer prior to their final year of high school and as they transitioned to the post-secondary level. Student acceptance of evolution was measured to be significantly higher than initial levels both immediately following and over one year after the educational experience. Results reported herein carry implications for future quantitative and qualitative research as well as for cross-disciplinary instruction plans related to evolutionary science and non-scientific factors which may influence student understanding of evolution. 相似文献
69.
Brian A. Bottge Enrique Rueda Jung Min Kwon Timothy Grant Perry LaRoque 《Educational technology research and development : ETR & D》2009,57(4):529-552
The purpose of this randomized experiment was to compare the performance of high-, average-, and low-achieving middle school
students who were assessed with parallel versions of a computer-based test (CBT) or a paper-pencil test (PPT). Tests delivered
in interactive, immersive environments like the CBT may have the advantage of providing teachers with diagnostic tools that
can lead to instruction tailored to the needs of students at different achievement levels. To test the feasibility of CBT,
students were randomly assigned to the CBT or PPT test conditions to measure what they had learned from an instructional method
called enhanced anchored math instruction. Both assessment methods showed that students benefited from instruction and differentiated
students by achievement status. The navigation maps generated from the CBT revealed that the low-achieving students were able
to navigate the test, spent about the same amount of time solving the subproblems as the more advanced students, and made
use of the learning scaffolds.
相似文献
Brian A. BottgeEmail: |
70.
Ron Tamborini Lindsay Hahn Brian Klebig Clare Grall 《Communication Research Reports》2017,34(1):58-67
A content analysis of children’s television examined the frequency with which behaviors were (a) driven by altruistic versus egoistic motivations, (b) performed by affable/surly characters, (c) rewarded/punished, and (d) present in content popular among different age groups (2–5, 6–11, and 12–17 years old). We found that portrayal patterns stressed the importance of egoistic motivations (particularly competence, autonomy, and relatedness) for older children. The findings are interpreted in line with logic underlying the model of intuitive morality and exemplars (MIME; Tamborini, 2013), suggesting that media representations can influence the motivations of their viewers. 相似文献