全文获取类型
收费全文 | 586篇 |
免费 | 15篇 |
国内免费 | 29篇 |
专业分类
教育 | 346篇 |
科学研究 | 98篇 |
各国文化 | 11篇 |
体育 | 92篇 |
综合类 | 68篇 |
文化理论 | 1篇 |
信息传播 | 14篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 17篇 |
2020年 | 18篇 |
2019年 | 13篇 |
2018年 | 17篇 |
2017年 | 12篇 |
2016年 | 19篇 |
2015年 | 16篇 |
2014年 | 54篇 |
2013年 | 56篇 |
2012年 | 53篇 |
2011年 | 37篇 |
2010年 | 27篇 |
2009年 | 42篇 |
2008年 | 31篇 |
2007年 | 40篇 |
2006年 | 30篇 |
2005年 | 31篇 |
2004年 | 18篇 |
2003年 | 15篇 |
2002年 | 17篇 |
2001年 | 12篇 |
2000年 | 17篇 |
1999年 | 8篇 |
1998年 | 7篇 |
1997年 | 4篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有630条查询结果,搜索用时 328 毫秒
101.
侯志敏 《河北职业技术学院学报》2009,(2)
葡萄糖代谢异常是2型糖尿病的主要病理生理改变,胰岛素依赖性和非胰岛素依赖性葡萄糖代谢通路的多个环节发生了异常改变,阐明2型糖尿病葡萄糖代谢异常的分子机制,对糖尿病的治疗和预防具有重大意义。 相似文献
102.
Based on the laboratory experiments with the saltwater and freshwater replacing each other in the level sand column, taking
the kaolin, illite, smectite, bivalent hydrargyrum ion (Hg2+) and phenol (C6H5OH) as examples, this paper studies the applications of water sensitivity in situ remediation in saltwater-freshwater transition zone. In the water sensitivity process, the release and migration of clay
minerals can make the hydraulic conductivity (HC) decrease and pollutants remove. A new type of low penetrable or impenetrable
purdah can be built by adding clay minerals into the sand media to replace the underground concrete impenetrable wall to prevent
seawater intrusion, and a number of the heavy metals and organic pollutants in the sand media can be removed by in situ remediation. The results show that the content of kaolin and illite influences the water sensitivity process slightly, and
HC of the sand columns descends from 0.011 cm/s to 0.001 4 cm/s and 0.001 2 cm/s respectively even if the content reaches
12% (weight ratio, sic passim). However, for smectite, HC descends sharply to about 1×10−8 cm/s when its content reaches 4%, and no water can flow through the sand columns beyond 5%. The particle release and migration
processes can remove the Hg2+ and C6H5OH out of the sand columns efficiently, the removing rate of Hg2+ is 31.68% when the freshwater and saltwater are filtered through the sand columns polluted by Hg2+, while it is 67.55% when the water sensitivity occurs. With the same method, the removing rates of C6H5OH under the fluid flow and water sensitivity are 55.71% and 43.43% respectively.
Supported by National Natural Science Foundation of China (No. 40572142).
HAN Zhiyong, born in 1976, male, Dr, associate Prof. 相似文献
103.
侯志敏 《廊坊师范学院学报(自然科学版)》2009,9(2):59-61
葡萄糖代谢异常是2型糖尿病的主要病理生理改变,胰岛素依赖性和非胰岛素依赖性葡萄糖代谢通路的多个环节发生了异常改变,阐明2型糖尿病葡萄糖代谢异常的分子机制,对糖尿病的治疗和预防具有重大意义。 相似文献
104.
根据1980—2015年河南省及周边39个气象站点逐日观测数据,选取与主要粮食作物生育机理相关的气候指标,运用气候统计方法分析河南省主要粮食作物生育期内水热气候要素的时空变化。结合统计数据,运用面板非线性回归模型分析主要粮食作物产量对气候变化的敏感性。研究发现:①河南省冬小麦返青期最低气温和生育期平均气温均呈显著增加趋势,在空间上两者升温速率呈现从河南省中部向周边递减的特征。夏玉米生育期总日照时数呈明显减少趋势,其减少速度在豫中地区最快,在豫西南地区最慢。②从敏感效应来看,冬小麦和夏玉米产量分别对生育期平均气温和生育期总日照时数的敏感效应最强,对生育期总降水量的敏感效应均最弱。从敏感区看,冬小麦产量敏感区主要分布在豫北、豫西和豫南地区,夏玉米则集中在豫西和豫东地区。③冬小麦生育期平均气温突变后有利于除豫北以外共83.3%区域内产量的增加,返青期最低气温突变后有利于豫北和豫东共44.4%区域内产量的增加。夏玉米生育期总日照时数突变后对豫中和豫西共44.4%区域的产量增加有利。 相似文献
105.
为研究优秀的网球职业运动员是否对球拍拍弦磅数变化有更好的区分能力以及拍弦磅数变化是否会影响到击球效果,本研究使用网球发球机发球,让18名优秀的网球职业运动员参加一个用不同拍弦磅数球拍的(从47磅~64磅)击球测试。从实验结果来看,61%测试者不能准确的区分6磅的拍弦磅数变化,击球后球飞行的平均速度是117 km/h,击球平均速度与落点失误数都与球拍拍弦磅数不存在显著性差异。研究结果表明,优秀网球职业运动员对网球拍弦磅数变化的分辨能力与敏感度较低;优秀的网球职业运动员击球的落点与球拍磅数不存在显著性相关;在底线击球中优秀的网球职业运动员对使用不同磅数的球拍有着很强的适应能力与控制能力。 相似文献
106.
浅议旅游业的敏感性和对策分析 总被引:1,自引:0,他引:1
韩苗 《商丘职业技术学院学报》2009,8(4):57-58
旅游业发展到今天,已成为朝阳型产业,在增进国民经济整体水平提升和外币创汇中起着举足轻重的作用。既然如此,如何使旅游业顺利健康沿着我们期望的方向发展,是我们研究的根本。本文是从分析旅游业的特点之一——敏感性作为切入点,洞悉其敏感性的实质,提出相应的对策,以便更好地引导旅游业的发展。 相似文献
107.
运用文献资料法、运动力学和数学分析等方法,建立了铅球投掷距离与铅球的出手速度、出手角度和出手高度三个因素之间关系的数学模型。利用MATLAB编程计算,通过作图逐层对影响铅球投掷成绩的因素进行了灵敏度分析和定量分析,分析了三个影响因素的主次关系,尤其是明确了一直以来备受争议的出手角度和出手高度的影响,为科学的训练、选材以及成绩的提高提供理论依据。 相似文献
108.
《European Journal of Sport Science》2013,13(2):152-160
Abstract The synergistic stimulating effect of combined intake of carbohydrate and protein on plasma insulin concentration has been reported previously. However, it remains unclear whether the amount of protein ingested after exercise affects the concentrations of plasma insulin and amino acids. This study of trained men compared the effects of post-exercise co-ingestion of carbohydrate plus different amounts of whey protein hydrolysates (WPHs) with carbohydrate alone on (1) blood biochemical parameters of carbohydrate metabolism during the post-exercise phase, and (2) endurance performance. Eight trained men exercised continuously for 70 min. Immediately after exercise and 30, 60, 90, and 120 min later, the participants received supplements containing: (1) 17.5 g carbohydrate, (2) 3.0 g WPHs and 17.5 g carbohydrate (L-WPH), or (3) 8.0 g WPHs and 17.5 g carbohydrate (H-WPH). After a 2-h recovery period, the participants performed an endurance performance test. The concentrations of blood glucose were lower and plasma insulin significantly higher in the H-WPH trial compared with the carbohydrate trial. The concentrations of plasma amino acids were increased in a dose-dependent manner following ingestion of different amounts of WPHs with carbohydrate. Endurance performance was not significantly different between the three trials. Co-ingestion of carbohydrate and H-WPH was more effective than ingestion of carbohydrate alone for stimulating insulin secretion and increasing the availability of plasma amino acids. These results suggest that plasma concentrations of amino acids during the recovery period are determined by the amount of dietary protein ingested, and that it is necessary to increase the concentration of plasma amino acids above a certain level to stimulate insulin secretion. 相似文献
109.
《European Journal of Sport Science》2013,13(2):221-230
Abstract It is currently unknown whether hypoxia training can effectively suppress overweight and hyperinsulinemia in genetically obese animals. In this study, both lean and obese Zucker rats were randomly assigned into the following groups: control (CON, n=7), exercise training (EX, n=7), hypoxia (HYP, n=7) and exercise training with hypoxia recovery (EX+HYP, n=7). During a 6-week training period, rats performed swimming exercise progressively from 30 to 180 min·day?1, and recovered under hypoxia (14% oxygen for 8 h·day?1). Obese Zucker rats exhibited substantially greater fasting insulin levels, and exaggerated glucose and insulin responses following an oral glucose challenge compared with lean rats. At the beginning of week 6, body weight, fasting glucose, fasting insulin, area under curve of glucose (GAUC) and insulin (IAUC) in the EX+HYP group were significantly lower than CON group among the obese rats. Meanwhile, only GAUC was significantly lower in the EX group compared to the CON group. At the end of week 6, capillaries to fibre ratio (C/F), capillary density (CD) and type IIa fibre proportion of the plantaris muscle in the EX group were significantly greater than the CON group (P<0.05), but no additive effect of hypoxia on exercise training was observed. Our data demonstrate that exercise training with prolonged hypoxia recovery offers better metabolic benefits than exercise training alone for the obese Zucker rats. This advantage was closely associated with effective weight reduction. 相似文献
110.
Konstantinos Niakaris Faidon Magkos Nikos Geladas Labros S Sidossis 《Journal of sports sciences》2013,31(10):1065-1073
The aims of the present study were to determine whether available “fasting” and oral glucose tolerance test-derived insulin sensitivity indices could effectively discriminate between individuals with higher than normal insulin sensitivity, and whether they would all provide similar information in clinical practice. Sprint runners (n = 8), endurance runners (n = 8) and sedentary controls (n = 7) received a 75-g oral glucose tolerance test. All participants were healthy lean males, aged 21?–?29 years. Besides glucose and insulin responses, a total of nine such indices were computed. Fasting as well as post-load glucose concentrations were similar in the three groups, while basal plasma insulin and the insulinaemic response to glucose were both higher in untrained individuals (at P?<?0.05 and P?<?0.02, respectively). There were no differences between endurance and sprint runners. The results for insulin sensitivity, however, were quite variable: three indices showed that both groups of athletes were more insulin-sensitive than controls; three indicated that this was the case for endurance runners only; one indicated that this was the case for sprint runners only; and two showed that sprint runners were more insulin-sensitive than either sedentary individuals or endurance runners (all differences were significant at P?<?0.05). Controlling for total body weight or lean mass did not effectively resolve this disagreement. Apparently, the various insulin sensitivity indices examined provided different quantitative and qualitative information, despite insulin action being greater in both groups of athletes relative to controls, as reflected by their similar glucose tolerance with lower insulin concentrations. We suggest, therefore, that the use and interpretation of such indices among physically active individuals be made with caution. 相似文献