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   125770篇
  免费   1624篇
  国内免费   281篇
教育   87456篇
科学研究   13551篇
各国文化   1994篇
体育   9664篇
综合类   204篇
文化理论   1068篇
信息传播   13738篇
  2021年   984篇
  2020年   1668篇
  2019年   2585篇
  2018年   3138篇
  2017年   3413篇
  2016年   3446篇
  2015年   2339篇
  2014年   3217篇
  2013年   27421篇
  2012年   2499篇
  2011年   2889篇
  2010年   2471篇
  2009年   2723篇
  2008年   2520篇
  2007年   2250篇
  2006年   2520篇
  2005年   2488篇
  2004年   3068篇
  2003年   2384篇
  2002年   2192篇
  2001年   2130篇
  2000年   1751篇
  1999年   1634篇
  1998年   1472篇
  1997年   1531篇
  1996年   1703篇
  1995年   1465篇
  1994年   1473篇
  1993年   1479篇
  1992年   1556篇
  1991年   1470篇
  1990年   1466篇
  1989年   1387篇
  1988年   1229篇
  1987年   1164篇
  1986年   1191篇
  1985年   1450篇
  1984年   1316篇
  1983年   1296篇
  1982年   1262篇
  1981年   1184篇
  1980年   1168篇
  1979年   1279篇
  1978年   1225篇
  1977年   1124篇
  1976年   1010篇
  1975年   822篇
  1974年   826篇
  1973年   792篇
  1971年   652篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
目的探讨尿素酶型纤溶酶原激活物(urokinase-type plasminigen activator,uPA)、乙酰肝素酶(heparanase,HPA)在卵巢上皮癌和淋巴结转移癌中表达及其与肿瘤侵袭的关系。方法应用免疫组化SABC法,对65例卵巢上皮肿瘤手术标本进行uPA和HPA蛋白表达的测定。结果uPA、HPA在卵巢上皮癌中阳性表达率分别为66.7%、51.1%,其明显高于良性肿瘤及正常组织,有淋巴结转移的肿瘤的阳性表达率分别为78.1%、62.5%,无淋巴结转移的肿瘤阳性表达率分别为38.1%、23.1%,uPA和HPA高表达与卵巢癌侵袭和淋巴结转移关系密切(P<0.05)。uPA和HPA在卵巢癌中的表达无显著性差异(P>0.05)表达成正相关(r=0.724)。结论uPA和HPA蛋白的表达与卵巢癌的侵袭和转移有显著的相关性。  相似文献   
92.
    
There is an increasing interest in linking character education programs with social and academic outcomes. The Child Development Project (CDP) is a character education program that promotes academic and social growth in teachers and students. This theory-driven evaluation employed a quasi-experimental design with matched control schools. School personnel participated in an intensive professional development process to learn the CDP model. Performance measures included state-mandated achievement measures, teacher self-assessment reports, and student attitudes and outcomes. Results yielded support for the CDP model as a strategy to improve social and, if properly implemented, cognitive outcomes in students; the model also improved teacher self-assessment and provided information that may facilitate professional growth about school collegiality. Implications for policy and practice will be discussed.  相似文献   
93.
What legal issues may arise in setting content or performance standards? What precedents are relevant? What practices are defensible?  相似文献   
94.
Conclusion Computer-based career systems should be the focal point of popular, and effective career development initiatives which are of tremendous benefit to individuals. Such initiatives also have the potential to significantly reduce public expenditures and enhance the nation's competitive position internationally. The key lies in helping people understand that we can no longer afford to neglect the career development needs of Americans.I am most grateful for this opportunity to share my thoughts with you. I encourage you to promote the use of computer-based career systems by defining their benefits in economic terms. However, be sure you can prove your system does more than simply entertain its users, or leave them with extensive computer printouts.Phillip S. Jarvis is Manager, Careerware Research and Product Design, STM Systems Corp., Ottawa, Ontario, Canada and the author of CHOICES. This is the text of a paper presented to the Annual Conference of the Association of Computer-Based Systems for Career Information ((ACSCI) in St. Louis, Missouri on December 2, 1988.  相似文献   
95.
There is limited information on the anthropometry, strength, endurance and flexibility of female rock climbers. The aim of this study was to compare these characteristics in three groups of females: Group 1 comprised 10 elite climbers aged 31.3 +/- 5.0 years (mean +/- s) who had led to a standard of 'hard very severe'; Group 2 consisted of 10 recreational climbers aged 24.1 +/- 4.0 years who had led to a standard of 'severe'; and Group 3 comprised 10 physically active individuals aged 28.5 +/- 5.0 years who had not previously rock-climbed. The tests included finger strength (grip strength, finger strength measured on climbing-specific apparatus), flexibility, bent arm hang and pull-ups. Regression procedures (analysis of covariance) were used to examine the influence of body mass, leg length, height and age. For finger strength, the elite climbers recorded significantly higher values (P < 0.05) than the recreational climbers and non-climbers (four fingers, right hand: elite 321 +/- 18 N, recreational 251 +/- 14 N, non-climbers 256 +/- 15 N; four fingers, left hand: elite 307 +/- 14 N, recreational 248 +/- 12 N, non-climbers 243 +/- 11 N). For grip strength of the right hand, the elite climbers recorded significantly higher values than the recreational climbers only (elite 338 +/- 12 N, recreational 289 +/- 10 N, non-climbers 307 +/- 11 N). The results suggest that elite climbers have greater finger strength than recreational climbers and non-climbers.  相似文献   
96.
97.
98.
裁判员在基本体操比赛评分中的心理行为及其调控   总被引:1,自引:0,他引:1  
通过对裁判员在基本体操比赛评分中各种心理活动的行为分类及分析,提出了基本的管理及调控方法。  相似文献   
99.
100.
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