全文获取类型
收费全文 | 615篇 |
免费 | 8篇 |
国内免费 | 1篇 |
专业分类
教育 | 427篇 |
科学研究 | 95篇 |
各国文化 | 3篇 |
体育 | 57篇 |
综合类 | 5篇 |
文化理论 | 5篇 |
信息传播 | 32篇 |
出版年
2022年 | 14篇 |
2021年 | 12篇 |
2020年 | 17篇 |
2019年 | 20篇 |
2018年 | 30篇 |
2017年 | 27篇 |
2016年 | 24篇 |
2015年 | 11篇 |
2014年 | 27篇 |
2013年 | 88篇 |
2012年 | 18篇 |
2011年 | 24篇 |
2010年 | 14篇 |
2009年 | 16篇 |
2008年 | 16篇 |
2007年 | 18篇 |
2006年 | 10篇 |
2005年 | 10篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 16篇 |
2000年 | 5篇 |
1999年 | 12篇 |
1998年 | 12篇 |
1997年 | 8篇 |
1995年 | 5篇 |
1994年 | 7篇 |
1992年 | 5篇 |
1990年 | 6篇 |
1989年 | 9篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1984年 | 3篇 |
1980年 | 9篇 |
1979年 | 5篇 |
1978年 | 7篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1975年 | 3篇 |
1974年 | 2篇 |
1973年 | 2篇 |
1971年 | 2篇 |
1967年 | 2篇 |
1960年 | 2篇 |
1957年 | 2篇 |
1947年 | 2篇 |
1934年 | 2篇 |
1841年 | 3篇 |
排序方式: 共有624条查询结果,搜索用时 15 毫秒
11.
Proteins and glutathione (GSH) levels were estimated in the experimental groups. Levels of both proteins and glutathione in
the control and the treated groups were found to be significantly decreased compared to the normal group. The results show
that supplementation of riboflavin has beneficial effect by alleviating the oxidant injuries to GSH and proteins, which are
involved in the maintenance of transparency and protection of thiol groups of the lens. Thus, riboflavin has an active role
in the lens metabolism and has a potential to improve the metabolic activity of the cataractous lenses. 相似文献
12.
13.
利用低温炭化法来制备柚子皮活性炭吸附剂。探讨了吸附剂用量、温度、pH值、Cr(Ⅵ)初始浓度、吸附时间等对吸附效果的影响。柚子皮吸附剂吸附处理Cr(Ⅵ)的最佳工艺条件是:吸附剂用量10g/L,温度40℃,pH=4,吸附时间10h,Cr(Ⅵ)初始浓度为100mg/L时,Cr(Ⅵ)的去除率能达到98%以上。柚子皮吸附剂对Cr(Ⅵ)具有良好的吸附能力,吸附过程符合二级吸附动力学模型并且可用Langmuir吸附等温线来描述。 相似文献
14.
The effects of orally presented storybook models on children's cognitive achievement behavior were assessed in two experiments. Experiment I involved 100 preschool-age children who were given one exposure to either a story depicting achievement behaviors by a male/female model, or a control story describing no achievement behavior. Subjects then were asked to perform a related achievement task. No significant modeling effects were found, but a significant relationship existed between the children's recall of the story content and their performance on the subsequent task. Experiment 11 employed 60 preschool-age children who were given repeated exposures (3 to 4) to, and group discussion of, the same achievement stories or non-achievement control story. A significant relationship was observed between type of story and type of solutions to the subsequent achievement task. These findings are discussed in the context of modeling theory, with practical implications. 相似文献
15.
16.
17.
This paper is concerned with the analysis of the problem of dynamic perforation of visco-plastic plates by a cylindrical projectile, leading to a failure of the plate by a plug formation. Assuming the behavior of the plate material is nonlocal visco-plastic, the classical theory of visco-plasticity for Bingham solids is generalized to take the non-local effects into consideration. The target plate being thin, it is assumed that only the contributions of vertical shearing stress need be taken into account. The effect of the impact is represented by a uniform velocity distribution over a circular region of the plate surface. The expressions of velocity, strain rate and shear stress are obtained and some particular cases are discussed. Some numerical results concerning stress distributions are also included. 相似文献
18.
19.
Differences in motor performance according to chronological age and gender of 341 young Nigerian children (ages 3 to 5) were examined. Motor test items designed by Morris et al. (1981) were administered to the subjects. Analysis of variance was used to determine significant differences in the motor performance of the groups. In the whole sample, more age differences than sex differences in performance were noted. Except for the balancing and running performances of the girls, a fairly linear trend of improvement with age was observed in the motor performances of the groups. At each age level the boys consistently performed better than the girls in four of the six motor tests (catching, standing long jump, tennis ball throw and speed run). Generally, the 4- and 5-year-old children performed homogeneously, with a great disparity in performance noted for the 3-year-old children. The results of this study confirm that age and sex differences in motor performance occur at early childhood. Prospective studies should seek to control the extraneous factors which influence motor development and account for the observed differences in motor performance of pre-school children. 相似文献
20.
广东省普通高校体育招生考试排球专项考试方法的研究 总被引:2,自引:1,他引:1
运用献资料、调查访问和实验等方法,对广东省普通高等学校体育招生考试排球专业考试内容、方法及评分标准等问题进行了深入细致的研究和探讨,阐述了调整和修改体育高考排球专项考试方法的必要性,并提出了新的体育高考排球专项考试内容、方法及评分标准。 相似文献