全文获取类型
收费全文 | 49619篇 |
免费 | 1040篇 |
国内免费 | 1223篇 |
专业分类
教育 | 28249篇 |
科学研究 | 9496篇 |
各国文化 | 141篇 |
体育 | 3601篇 |
综合类 | 2866篇 |
文化理论 | 280篇 |
信息传播 | 7249篇 |
出版年
2024年 | 15篇 |
2023年 | 73篇 |
2022年 | 604篇 |
2021年 | 1501篇 |
2020年 | 1091篇 |
2019年 | 614篇 |
2018年 | 560篇 |
2017年 | 695篇 |
2016年 | 605篇 |
2015年 | 1695篇 |
2014年 | 2493篇 |
2013年 | 3128篇 |
2012年 | 3747篇 |
2011年 | 3980篇 |
2010年 | 3776篇 |
2009年 | 3391篇 |
2008年 | 3349篇 |
2007年 | 3627篇 |
2006年 | 3508篇 |
2005年 | 2948篇 |
2004年 | 1715篇 |
2003年 | 1621篇 |
2002年 | 1711篇 |
2001年 | 1517篇 |
2000年 | 1028篇 |
1999年 | 804篇 |
1998年 | 511篇 |
1997年 | 361篇 |
1996年 | 321篇 |
1995年 | 165篇 |
1994年 | 184篇 |
1993年 | 114篇 |
1992年 | 117篇 |
1991年 | 76篇 |
1990年 | 44篇 |
1989年 | 61篇 |
1988年 | 23篇 |
1987年 | 9篇 |
1986年 | 10篇 |
1985年 | 12篇 |
1984年 | 17篇 |
1983年 | 18篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1957年 | 21篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
偶氮染料废水的处理方法及研究进展 总被引:1,自引:0,他引:1
偶氮染料废水是一种有机物含量高、成分复杂、色度高、可生化性差的难降解废水,其处理方法已引起广泛关注。本文阐述了物理法、化学法和生物法3种废水处理方法在偶氮染料废水处理中的应用,并对各种方法进行了评述,展望了今后的发展方向。 相似文献
993.
994.
加强和改进大学生思想政治教育的关键在于与时俱进、不断创新。要以科学发展观为指导,依据不断变化的新形势和新任务,提出新思路、新目标和新方法。要坚持以学生为本的原则,改革大学生思想政治教育的内容、途径、方法和手段,走一条新世纪新阶段大学生思想政治教育的创新之路。 相似文献
995.
贵州省苗族地区中小学民族文化课程开发的个案研究 总被引:1,自引:0,他引:1
通过对贵州省苗族地区中小学民族文化课程开发现状的个案调查,发现民族地区民族文化课程开发还停留在浅层面,学校课程尚未成为民族文化传承的主渠道,地方课程资源开发不力,致使学生对民族义化疏于了解。就此认为民族地区基础教育民族文化课程的开发应从观念层面、政策层面、支持系统及实践层面等方面进行,以推进民族文化课程的实施。 相似文献
996.
Proteomic analysis of human umbilical vein endothelial cells exposed to PM<Subscript>2.5</Subscript>
Ji Zhu Lin-wen-si Zhu Jin-huan Yang Ying-ling Xu Cui Wang Zhuo-yu Li Wei Mao De-zhao Lu 《Journal of Zhejiang University. Science. B》2018,19(6):458-470
Exposure to fine ambient particulate matter (PM2.5) is known to be associated with cardiovascular disease. To uncover the molecular mechanisms involved in cardiovascular toxicity of PM2.5, we investigated alterations in the protein profile of human umbilical vein endothelial cells (HUVECs) treated with PM2.5 using two-dimensional electrophoresis in conjunction with mass spectrometry (MS). A total of 31 protein spots were selected as differentially expressed proteins and identified by matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) MS. The results demonstrated that DNA damage and cell apoptosis are important factors contributing to PM2.5-mediated toxicity in HUVECs. It is further proposed that PM2.5 can inhibit superoxide dismutase (SOD) activity and increase reactive oxygen species (ROS) and malonaldehyde (MDA) production in a concentration-dependent manner. Induction of apoptosis and DNA damage through oxidative stress pathways may be one of the key toxicological events occurring in HUVECs under PM2.5 stress. These results indicated that the toxic mechanisms of PM2.5 on cardiovascular disease are related to endothelial dysfunction. 相似文献
997.
The purpose of the current study was to investigate a two-stage model in which parent-related stress and hopelessness each served as mediators of the relationship between perceived parental bonding and South Korean adolescent peer victimization. This study also examined whether the mediating relationships differed by the gender of parents and adolescents. A casual chain with three links and four sets of variables were analyzed using structural equation modeling. Data were collected from 800 adolescents attending 10 middle schools in the Busan region of South Korea. Results indicated that both maternal and paternal parental bonding were negatively associated with stress, stress was positively associated with hopelessness, and hopelessness was positively associated with South Korean adolescent peer victimization. Most importantly, the significant negative associations between both maternal and paternal parental bonding and peer victimization were mediated by both stress and hopelessness. Furthermore, gender differences in these relationships existed for both parents and adolescents. Limitations and implications to practice were discussed. 相似文献
998.
INTRODUCTION Plants have defense mechanisms against patho-gen infection by inducing systemic resistance in re-sponse to localized pretreatment with biological cotrol agents, thus making them resistant to subsequpathogen infection (Caruso et al., 1999; Hammschmidt, 1999; Mohammadi and Kazemi, 2002; yada et al., 1995; Pozo et al., 2002; Ray et al., 199Biological control of plant pathogens has receivmuch more attention. It is well known that plants amicroorganisms symbiosis is a defense m… 相似文献
999.
屯堡文化的时空建构 总被引:4,自引:0,他引:4
吴羽 《安顺师范高等专科学校学报》2004,6(3):72-75
屯堡文化的能够传承至今,与当时的历史背景和黔中独特的地理环境有着非常密切的关系,屯堡文化不是一成不变的,而是处在一个不断建构、不断完善的过程中,是有机的时空建构的结果. 相似文献
1000.