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   13644篇
  免费   182篇
  国内免费   21篇
教育   9508篇
科学研究   1538篇
各国文化   126篇
体育   1183篇
综合类   6篇
文化理论   103篇
信息传播   1383篇
  2021年   141篇
  2020年   197篇
  2019年   272篇
  2018年   381篇
  2017年   358篇
  2016年   369篇
  2015年   242篇
  2014年   320篇
  2013年   2357篇
  2012年   304篇
  2011年   321篇
  2010年   282篇
  2009年   224篇
  2008年   270篇
  2007年   244篇
  2006年   236篇
  2005年   215篇
  2004年   236篇
  2003年   206篇
  2002年   177篇
  2001年   448篇
  2000年   295篇
  1999年   257篇
  1998年   119篇
  1997年   156篇
  1996年   134篇
  1995年   124篇
  1994年   149篇
  1993年   112篇
  1992年   183篇
  1991年   191篇
  1990年   194篇
  1989年   198篇
  1988年   167篇
  1987年   160篇
  1986年   167篇
  1985年   205篇
  1984年   162篇
  1983年   150篇
  1982年   129篇
  1981年   123篇
  1980年   117篇
  1979年   163篇
  1978年   133篇
  1977年   117篇
  1976年   92篇
  1975年   115篇
  1974年   102篇
  1973年   107篇
  1971年   98篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
The aims of this study were to describe normative values and seasonal variation of body composition in female cyclists comparing female road and track endurance cyclists, and to validate the use of anthropometry to monitor lean mass changes. Anthropometric profiles (seven site skinfolds) were measured over 16 years from 126 female cyclists. Lean mass index (LMI) was calculated as body weight?×?skinfolds?x. The exponent (x) was calculated as the slope of the natural logarithm of body weight and skinfolds. Percentage changes in LMI were compared to lean mass changes measured using dual-energy X-ray absorptiometry (DXA) in a subset of 25 road cyclists. Compared to sub-elite and elite cyclists, world class cyclists were (mean [95% CI]) 1.18?kg [0.46, 1.90] and 0.60?kg [0.05, 1.15] lighter and had skinfolds that were 7.4?mm [3.8, 11.0] and 4.6?mm [1.8, 7.4] lower, respectively. Body weight (0.41?kg [0.04, 0.77]) and skinfolds (4.0?mm [2.1, 6.0]) were higher in the off-season compared to the early-season. World class female road cyclists had lower body weight (6.04?kg [2.73, 9.35]) and skinfolds (11.5?mm [1.1, 21.9]) than track endurance cyclists. LMI (mean exponent 0.15 [0.13, 0.18]) explained 87% of the variance in DXA lean mass. In conclusion, higher performing female cyclists were lighter and leaner than their less successful peers, road cyclists were lighter and leaner than track endurance cyclists, and weight and skinfolds were lowest early in the season. LMI appears to be a reasonably valid tool for monitoring lean mass changes.  相似文献   
992.
Serum glycoproteins were evaluated in oral squamous cell carcinoma patients treated with radiotherapy and also the effect of vitamin E was studied. Cell surface glycoconjugates are important parameters in the detection of malignancy. Thus, the objective of the present study is to evaluate the efficacy of vitamin E on glycoproteins in oral cavity cancer patients treated with radiotherapy. The study includes 26 age and sex matched normal healthy individuals and 26 patients with squamous cell carcinoma of oral cavity. These patients were divided into two groups, one for radiotherapy alone (at a dosage of 6000 cGy in five fractions per week for a period of six weeks) and the other for radiotherapy plus vitamin E supplementation (at a dosage of 400 IU / day of vitamin E) for the entire period of radiotherapy. Levels of hexose, hexosamine, fucose and sialic acid were increased in oral squamous cell carcinoma patients and a significant decrease was observed in radiation treated patients when compared to control. The levels of glycoconjugates were significantly decreased in radiation treated patients supplemented with vitamin E. This measurement may be useful in assessing disease progression and identifying patients resistant to therapy and a possible role of vitamin E on reduction in glycoconjugate levels of radiation treated oral squamous cell carcinoma patients.  相似文献   
993.
Investigations employing primates have sometimes used tests of concurrent object-discrimination as indexes of multiproblem memory in comparative studies of neuropathological impairment. The present investigation was an attempt to employ a comparable test procedure with rats. Data from two experiments indicated that rats could indeed be trained on a concurrent object-discrimination task. Furthermore, results from the second experiment indicated that these performances and brightness discriminations shared the property of disruption by posterior decortication. Implications for the neuropsychology of learning and memory are discussed.  相似文献   
994.
995.
Abstract In this article, we describe the development and evaluation of a beginning spelling intervention for young children at risk of reading disability. We first summarize the literature that supports beginning spelling as an ideal method for strategically integrating the beginning reading big ideas of phonemic awareness and alphabetic understanding. We then summarize the literature on effective instructional principles for students at risk of reading disability. Next, we describe how instructional design was applied to the development of an intervention for young children at risk of reading disability, then summarize the findings of an experimental study supporting the effectiveness of this intervention. Finally, we provide selected examples from the spelling intervention to illustrate the findings' translation into instructional practice.  相似文献   
996.
997.
998.
从“学生投入”的角度,对体育教学中普遍存在的学生外显的积极行为和内隐的消极心理这一矛盾进行深入分析,认为体育教学应该重视学生积极情感的投入,减少遵守规范式和消极情感式的情感投入;重视学生积极性的认知投入,减少表面性的认知投入;重视学生积极的行为投入,减少消极的行为投入。  相似文献   
999.
掷标枪技术训练要从基础训练阶段(13~15岁)抓起。通过实验对照分析找出一个较为理想的符合该年龄段特点的掷标枪技术训练的计划安排和练习方法,以及该年龄段掌握技术的要求。  相似文献   
1000.
对艺术体操运动员舞蹈基本功的早期训练,从训练的任务、特点、内容、教法建议等方面进行了研究与探讨。  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