全文获取类型
收费全文 | 1523篇 |
免费 | 24篇 |
国内免费 | 1篇 |
专业分类
教育 | 1045篇 |
科学研究 | 74篇 |
各国文化 | 12篇 |
体育 | 231篇 |
综合类 | 1篇 |
文化理论 | 15篇 |
信息传播 | 170篇 |
出版年
2023年 | 8篇 |
2022年 | 8篇 |
2021年 | 10篇 |
2020年 | 29篇 |
2019年 | 54篇 |
2018年 | 53篇 |
2017年 | 49篇 |
2016年 | 57篇 |
2015年 | 42篇 |
2014年 | 35篇 |
2013年 | 387篇 |
2012年 | 32篇 |
2011年 | 46篇 |
2010年 | 38篇 |
2009年 | 27篇 |
2008年 | 39篇 |
2007年 | 51篇 |
2006年 | 30篇 |
2005年 | 21篇 |
2004年 | 22篇 |
2003年 | 25篇 |
2002年 | 28篇 |
2001年 | 22篇 |
2000年 | 28篇 |
1999年 | 23篇 |
1998年 | 12篇 |
1997年 | 10篇 |
1996年 | 12篇 |
1995年 | 10篇 |
1994年 | 14篇 |
1993年 | 20篇 |
1992年 | 18篇 |
1991年 | 17篇 |
1990年 | 14篇 |
1989年 | 15篇 |
1988年 | 12篇 |
1987年 | 9篇 |
1986年 | 16篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 17篇 |
1982年 | 17篇 |
1981年 | 15篇 |
1980年 | 6篇 |
1979年 | 12篇 |
1978年 | 10篇 |
1977年 | 10篇 |
1975年 | 13篇 |
1973年 | 9篇 |
1972年 | 5篇 |
排序方式: 共有1548条查询结果,搜索用时 0 毫秒
91.
92.
93.
94.
Formulae are derived for the deflection surface of a symmetrically loaded circular plate having several points supports which are situated at equal distances apart on a single concentric circle. There is no restriction on the diameter of the support circle, which may be as large as the diameter of the plate itself. The results of this paper compare favorably with published experimental results. Numerical deflection coefficients for a uniformly loaded plate are provided, and these could be utilized for optimizing the positions and the number of concentrated supports. 相似文献
95.
96.
Janet M. Batzli Amber R. Smith Paul H. Williams Seth A. McGee Katalin Dósa Jesse Pfammatter 《CBE life sciences education》2014,13(3):410-424
Genetics instruction in introductory biology is often confined to Mendelian genetics and avoids the complexities of variation in quantitative traits. Given the driving question “What determines variation in phenotype (Pv)? (Pv=Genotypic variation Gv + environmental variation Ev),” we developed a 4-wk unit for an inquiry-based laboratory course focused on the inheritance and expression of a quantitative trait in varying environments. We utilized Brassica rapa Fast Plants as a model organism to study variation in the phenotype anthocyanin pigment intensity. As an initial curriculum assessment, we used free word association to examine students’ cognitive structures before and after the unit and explanations in students’ final research posters with particular focus on variation (Pv = Gv + Ev). Comparison of pre- and postunit word frequency revealed a shift in words and a pattern of co-occurring concepts indicative of change in cognitive structure, with particular focus on “variation” as a proposed threshold concept and primary goal for students’ explanations. Given review of 53 posters, we found ∼50% of students capable of intermediate to high-level explanations combining both Gv and Ev influence on expression of anthocyanin intensity (Pv). While far from “plug and play,” this conceptually rich, inquiry-based unit holds promise for effective integration of quantitative and Mendelian genetics. 相似文献
97.
98.
Assessment of the effectiveness of the studio format in introductory undergraduate biology 下载免费PDF全文
Kansas State University converted its introductory biology course, previously taught as an audio-tutorial (A-T), to a studio format in 1997. We share with others information about the process involved and present assessment data for the studio format course that address 1) student exam performance in A-T and studio; 2) student course grades in A-T and studio; 3) student and instructor perceptions and attitudes for A-T and studio; 4) student performance in subsequent biology courses for A-T and studio; and 5) gains in student learning for the studio course and other traditional lecture/lab courses. Collectively, these measures demonstrate that the studio format is as effective as or more effective (for some measures) than the A-T approach and traditional approaches in providing an effective learning environment. We discuss the issues involved in comparing course formats. 相似文献
99.
In this review, we attempt to integrate the main research findings concerned with talent identification and development in soccer. Research approaches in anthropometry, physiology, psychology and sociology are considered and, where possible, integrated. Although some progress has been made in identifying correlates of playing success, it appears that no unique characteristics can be isolated with confidence. Both biological and behavioural scientists have indicated a strong genetic component in performance of sports such as soccer; nevertheless, the influence of systematic training and development programmes should not be underestimated. Weconclude that the sport and exercise sciences have an important support role in the processes of identifying, monitoring and nurturing talented soccer players towards realizing their potential. 相似文献
100.