全文获取类型
收费全文 | 2026篇 |
免费 | 28篇 |
国内免费 | 4篇 |
专业分类
教育 | 1454篇 |
科学研究 | 262篇 |
各国文化 | 25篇 |
体育 | 98篇 |
综合类 | 1篇 |
文化理论 | 36篇 |
信息传播 | 182篇 |
出版年
2021年 | 20篇 |
2020年 | 28篇 |
2019年 | 48篇 |
2018年 | 63篇 |
2017年 | 54篇 |
2016年 | 47篇 |
2015年 | 33篇 |
2014年 | 39篇 |
2013年 | 546篇 |
2012年 | 41篇 |
2011年 | 44篇 |
2010年 | 33篇 |
2009年 | 22篇 |
2008年 | 43篇 |
2007年 | 25篇 |
2006年 | 29篇 |
2005年 | 28篇 |
2004年 | 34篇 |
2003年 | 33篇 |
2002年 | 34篇 |
2001年 | 19篇 |
2000年 | 25篇 |
1999年 | 24篇 |
1998年 | 19篇 |
1997年 | 22篇 |
1996年 | 25篇 |
1995年 | 18篇 |
1994年 | 13篇 |
1993年 | 23篇 |
1992年 | 19篇 |
1991年 | 17篇 |
1990年 | 17篇 |
1989年 | 23篇 |
1988年 | 14篇 |
1987年 | 25篇 |
1986年 | 14篇 |
1985年 | 12篇 |
1984年 | 16篇 |
1983年 | 15篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 20篇 |
1979年 | 15篇 |
1978年 | 19篇 |
1976年 | 12篇 |
1974年 | 14篇 |
1972年 | 11篇 |
1968年 | 11篇 |
1967年 | 14篇 |
1966年 | 12篇 |
排序方式: 共有2058条查询结果,搜索用时 15 毫秒
101.
In this paper, we utilize transmission-line matrix simulations to study the electromagnetic properties of hyperbolic metamaterial grids, which are synthesized by arranging unloaded transmission lines over electrical ground planes, such that the unit cells are rectangular in shape. The hyperbolic grids support Bragg and Hyperbolic resonant modes that have rectangular and hyperbolic dispersion surfaces, respectively. We demonstrate the formation of these resonant modes in the hyperbolic grids and their refraction, and spatial scanning properties via circuit simulations. The simulation results are compared with experimental results of a two-layer anisotropic hyperbolic metamaterial. 相似文献
102.
Gruson D Ahn SA Rousseau MF 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2011,21(3):254-263
Heart failure (HF) is a frequent chronic disease in elderly people and represents a major health and economic burden. The accurate diagnosis of HF and the identification of high risk patients is mandatory to select the appropriate therapy and care. HF is associated to cardiac remodeling and inflammation and to the release of neurohormones. If natriuretic peptides remain the biomarkers of choice for the diagnosis and the prognosis of HF, several biomarkers related to cardiac remodeling and inflammation are available for testing and may add valuable information for the risk estimation of HF patients and for the selection of the most appropriated therapy. Furthermore, the quest for new efficient biomarkers of cardiac remodeling and inflammation is still ongoing and new candidates have been identified for a potential use in daily clinical practices. However, before their potential translation to routine parameters several challenges ranging form the analytical validation to the cost-effectiveness estimation should be considered. 相似文献
103.
Saraslanidis P Petridou A Bogdanis GC Galanis N Tsalis G Kellis S Mougios V 《Journal of sports sciences》2011,29(11):1167-1174
Repeated-sprint training often involves short sprints separated by inadequate recovery intervals. The effects of interval duration on metabolic and performance parameters are unclear. We compared the effects of two training programmes, differing in rest interval duration, on muscle (vastus lateralis) metabolism and sprint performance. Sixteen men trained three times a week for 8 weeks, each training session comprising 2-3 sets of two 80-m sprints. Sprints were separated by 10 s (n = 8) or 1 min (n = 8). Both training programmes improved performance in the 100-, 200-, and 300-m sprints, but the improvement was greater in the 10-s group during the final 100 m of the 200- and 300-m runs. Independent of interval duration, training mitigated the drop of muscle ATP after two 80-m sprints. The drop in phosphocreatine and the increases in glucose-6-phosphate and fructose-6-phosphate after two 80-m sprints were greater in the 10-s group. In conclusion, training with a limited number of repeated short sprints (≤10 s) may be more effective in improving speed maintenance in 200- and 300-m runs when performed with a 1:1 rather than a 1:6 exercise-to-rest ratio. This may be due to a greater activation of glycolysis caused, in part, by the limited resynthesis of phosphocreatine during the very short rest interval. 相似文献
104.
Much research has examined shoulder range of motion adaptations in overhead-unilateral athletes. Based on the void examining overhead-bilateral athletes, especially competitive swimmers, we examined shoulder external rotation, isolated internal rotation, composite internal rotation, and total arc of motion range of motion of competitive swimmers. The range of motion of registered competitive swimmers (n = 144, age = 12-61 years) was compared by limb (dominant, non-dominant), sex, and age group (youth, high school, college, masters). Significantly (P < 0.05) greater dominant external rotation was observed for both men and women high school and college swimmers, youth women swimmers, and men masters swimmers compared with the non-dominant limb. The isolated internal rotation (glenohumeral rotation), composite internal rotation (glenohumeral rotation plus scapulothoracic protraction), and total arc of motion (external rotation plus composite internal rotation) of the non-dominant limb was significantly greater than that of the dominant limb by sex and age group. Youth and high school swimmers demonstrated significantly greater composite internal rotation than college and masters swimmers. Youth swimmers displayed significantly greater total arc of motion than all other age groups. These data will aid in the interpretation of shoulder range of motion values in competitive swimmers during preseason screenings, injury evaluations and post-rehabilitation programmes, with the results suggesting that differences exist in bilateral external rotation, isolated internal rotation, composite internal rotation, and total arc of motion range of motion. 相似文献
105.
George Vukotich 《Performance Improvement》2014,53(1):30-35
This article looks at 360° feedback, as well as mistakes and misuses that are often made in its implementation and use. Too often individuals look for tools to give them facts to support predetermined opinions rather than gathering facts to support individuals in their growth and development process. By identifying these issues and addressing them up front, larger issues that can negatively affect the overall culture of an organization can be avoided. 相似文献
106.
……当春天从玫瑰红的云彩中露出她的碧眼,当阳光在我的书桌上闪烁时,我渴望的发疯般地闻一闻那百花绽放的大地的芳香,看一看那山坡上落叶松的葱郁,听一听高地上云雀的歌唱。曾几何时,似乎比童年还要遥远的那个时刻,我满腔热情地拿起了笔。如果那时我的手在颤抖,那也只是因为希 相似文献
107.
108.
109.
110.