首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6303篇
  免费   96篇
  国内免费   84篇
教育   4465篇
科学研究   773篇
各国文化   21篇
体育   498篇
综合类   313篇
文化理论   55篇
信息传播   358篇
  2023年   22篇
  2022年   90篇
  2021年   176篇
  2020年   160篇
  2019年   172篇
  2018年   162篇
  2017年   174篇
  2016年   169篇
  2015年   281篇
  2014年   402篇
  2013年   768篇
  2012年   481篇
  2011年   538篇
  2010年   467篇
  2009年   377篇
  2008年   391篇
  2007年   373篇
  2006年   335篇
  2005年   234篇
  2004年   140篇
  2003年   129篇
  2002年   89篇
  2001年   76篇
  2000年   44篇
  1999年   17篇
  1998年   17篇
  1997年   18篇
  1996年   18篇
  1995年   18篇
  1994年   17篇
  1993年   10篇
  1992年   10篇
  1990年   8篇
  1989年   8篇
  1988年   4篇
  1987年   3篇
  1986年   4篇
  1985年   3篇
  1984年   3篇
  1981年   4篇
  1980年   3篇
  1979年   8篇
  1978年   3篇
  1976年   3篇
  1974年   6篇
  1973年   3篇
  1972年   6篇
  1956年   3篇
  1872年   4篇
  1870年   4篇
排序方式: 共有6483条查询结果,搜索用时 15 毫秒
31.
ABSTRACT

This research adapted the Life Skills Scale for Sport (LSSS) into Portuguese and provided evidence for its construct validity. Study 1 included four translators and five academics who developed a Portuguese version of the LSSS (P-LSSS). During this study, evidence for the content and substantive aspects of construct validity was provided using an expert panel and 25 sports participants. Study 2 included 413 participants that completed the P-LSSS. Within this study, evidence for the structural aspect of construct validity was provided via factor analyses. Study 3 included 134 participants who completed the P-LSSS and a measure of motivation. This study provided evidence for the external aspect of construct validity, with results showing more self-determined motivation had positive relationships with participant’s life skills development. Overall, our findings provided evidence for the construct validity of P-LSSS scores. Researchers and practitioners can use the P-LSSS to assess life skills development within sports participants.  相似文献   
32.
玉米淀粉接枝高吸水性树脂的合成研究   总被引:1,自引:0,他引:1  
对影响淀粉—丙烯酸接枝共聚反应的引发剂用量、淀粉/单体比例、聚合温度和聚合时间等因素进行了实验考察,确定了合成玉米淀粉接枝高吸水性树脂的最佳工艺条件。合成了吸水率为400g.g^-1~600g.g^-1的高吸水性树脂.为其工业化生产提供了技术参数。  相似文献   
33.
现代社会和谐的理想是政治正义和个人自由的美好契合和有机统一。一方面,以人为本,实现个人自由全面的发展是一个公正社会的最后目的。为了公平正义的社会大可不必牺牲个人自由,同时,个人自由可以检验社会公正。另.一方面,作为自由主体的人发出对公共秩序的需求,政治正义能够提供一种普遍公正和持久稳定的生活秩序,满足人们对稳定生活的秩序期待,也就是说政治正义可以约束和范导个人自由。  相似文献   
34.
Resin-dentin bond degradation is a major cause of restoration failures. The major aim of the current study was to evaluate the impact of a remineralization medium on collagen matrices of hybrid layers of three different adhesive resins using nanotechnology methods. Coronal dentin surfaces were prepared from freshly extracted premolars and bonded to composite resin using three adhesive resins (FluoroBond II, Xeno-III-Bond, and iBond). From each tooth, two central slabs were selected for the study. The slabs used as controls were immersed in a simulated body fluid (SBF). The experimental slabs were immersed in a Portland cement-based remineralization medium that contained two biomimetic analogs (biomineralization medium (BRM)). Eight slabs per group were retrieved after 1, 2, 3, and 4 months, respectively and immersed in Rhodamine B for 24 h. Confocal laser scanning microscopy was used to evaluate the permeability of hybrid layers to Rhodamine B. Data were analyzed by analysis of variance (ANOVA) and Tukey’s honest significant difference (HSD) tests. After four months, all BRM specimens exhibited a significantly smaller fluorescent area than SBF specimens, indicating a remineralization of the hybrid layer (P≤0.05). A clinically applicable biomimetic remineralization delivery system could potentially slow down bond degradation.  相似文献   
35.
探讨人机交互机理中感知系统模型和行为系统模型的基本原理与特点,总结出深入研究人机交互机理是实现虚拟现实人机交互的基础。同时指出人机交互感官机理研究有待进一步加强的方面。  相似文献   
36.
The purpose of this study was to compare the pedalling technique in road cyclists of different competitive levels. Eleven professional, thirteen elite and fourteen club cyclists were assessed at the beginning of their competition season. Cyclists’ anthropometric characteristics and bike measurements were recorded. Three sets of pedalling (200, 250 and 300 W) on a cycle ergometer that simulated their habitual cycling posture were performed at a constant cadence (~90 rpm), while kinetic and kinematic variables were registered. The results showed no differences on the main anthropometric variables and bike measurements. Professional cyclists obtained higher positive impulse proportion (1.5–3.3% and P < 0.05), mainly due to a lower resistive torque during the upstroke (15.4–28.7% and P < 0.05). They also showed a higher ankle range of movement (ROM, 1.1–4.0° and P < 0.05). Significant correlations (P < 0.05) were found between the cyclists’ body mass and the kinetic variables of pedalling: positive impulse proportion (r = ?0.59 to ?0.61), minimum (r = ?0.59 to ?0.63) and maximum torques (r = 0.35–0.47). In conclusion, professional cyclists had better pedalling technique than elite and club cyclists, because they opted for enhancing pulling force at the recovery phase to sustain the same power output. This technique depended on cycling experience and level of expertise.  相似文献   
37.
浅谈实践环节在教学过程中的重要性   总被引:3,自引:0,他引:3  
黄娟 《高教论坛》2002,(5):83-84
从实践教学和理论教学的特点出发,通过分析两者间的关系,论述了实践教学在教学改革过程中的重要性,并指出教学过程中两者应相辅相成、取长补短。  相似文献   
38.
介绍Pro/Engineer的Program参数化造型方法及其程序结构,并且以直齿锥齿轮为实例,详细地介绍Program参数化造型的实现过程。为同类产品实现参数化造型,减少重复劳动,提高设计效率提供一种适用、有效的方法。  相似文献   
39.
复句中的语义关系既是事物之间客观联系的反映,又是人们主观视角的反映。在事物之间的客观联系保持固定的情况下,人们的主观视角会随着认知需求的变化而变化。表现在复句中,则是适时添加复句关系词。并列范畴转化为因果范畴是人的特定视角的转化,这需要一定的客观条件,同时又必须有一定的认知作为前提。  相似文献   
40.
Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号