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   34338篇
  免费   2871篇
  国内免费   1838篇
  2023年   335篇
  2022年   389篇
  2021年   1582篇
  2020年   1035篇
  2019年   1253篇
  2018年   1226篇
  2017年   864篇
  2016年   1329篇
  2015年   2025篇
  2014年   2370篇
  2013年   2552篇
  2012年   3083篇
  2011年   2769篇
  2010年   1723篇
  2009年   1429篇
  2008年   1663篇
  2007年   1514篇
  2006年   1352篇
  2005年   1141篇
  2004年   1019篇
  2003年   866篇
  2002年   743篇
  2001年   677篇
  2000年   682篇
  1999年   657篇
  1998年   387篇
  1997年   336篇
  1996年   352篇
  1995年   333篇
  1994年   329篇
  1993年   217篇
  1992年   355篇
  1991年   271篇
  1990年   307篇
  1989年   257篇
  1988年   192篇
  1987年   172篇
  1986年   153篇
  1985年   138篇
  1984年   122篇
  1983年   95篇
  1982年   77篇
  1981年   60篇
  1980年   45篇
  1979年   74篇
  1978年   54篇
  1977年   52篇
  1975年   59篇
  1974年   47篇
  1973年   50篇
排序方式: 共有10000条查询结果,搜索用时 156 毫秒
981.
Wang  Chaojie  Gong  Yandong  Wei  Anbang  Huang  Tao  Hou  Siyuan  Du  Junjie  Li  Zongcheng  Wang  Junliang  Liu  Bing  Lan  Yu 《中国科学:生命科学英文版》2021,64(12):2073-2087
Science China Life Sciences - During embryogenesis, hematopoietic stem progenitor cells (HSPCs) are believed to be derived from hemogenic endothelial cells (HECs). Moreover, arterial feature is...  相似文献   
982.
Science China Life Sciences - Neutrophils are crucial for immunity and play important roles in inflammatory diseases; however, mouse models selectively deficient in neutrophils are limited, and...  相似文献   
983.
984.
Dear Editor,Myocardial infarction is one of the leading causes of morbidity and mortality.Stem/progenitor cells therapy has emerged as a promising strategy for the cardiac repair,especially those derived from cardiac tissue,have attracted worldwide attention(Tompkins et al.,2018).However,challenges and controversies remain in characterizing functional progenitors and explaining their mechanisms of action.  相似文献   
985.
The ongoing pandemic of coronavirus disease 2019(COVID-19)caused by a novel severe acute respiratory syndrome coronavirus 2(SARS-CoV-2,also named as 2019-nCoV or HCoV-19)poses an unprecedented threat to public health(Zhu et al.,2020;Wang et al.,2020;Jiang et al.,2020).The novel HCoV-19 virus has rapidly spread into multiple countries across the world since it was first reported in December 2019.The World Health Organization(WHO)declared COVID-19 as a pandemic on 11th March 2020.As of 4th July,over 10 million confirmed COVID-19 cases have been reported in over 200 countries/regions with more than 0.5 million deaths,including 85,287 documented cases and 4,648 deaths in China(WHO,2020a).  相似文献   
986.

Pursuing the rural idyll for retirement is especially a popular age-old dream for Taiwan people. Farming for health is an emerging trend, which drivers to initiate a green care service based on a combination of agriculture resources and traditional care. The purposes of this study were to assess the feasibility of green care in rural communities and to propose implementation strategies for varied rural area types in Taiwan. This study was conducted with two stags. A feasibility study comprising two aspects of political and environmental feasibilities was assessed in the first stage. The political feasibility was assessed based on social demand and government policies. Accordingly, three alternative models for senior green care participation were proposed, including green occupational therapy (for residents), rural long-stay tourism (for tourists), and agricultural working holiday (for volunteers). The environmental feasibility assessment was conducted in 102 rural communities in northern Taiwan. Five indexes, including the natural environment, rural resources, public facilities, senior care, and community capacity, were used to evaluate the potential of communities for developing green care. The results showed that green care implementing active aging in place in rural areas is feasible. Seventeen communities with plentiful or unique rural resources and high-quality community capacity were recommended as potential communities. In the second stage, a multiple case study was conducted in three communities representing different alternative models of green care. The community leader interviews, on-site investigations, vision forum, and operation workshop were adopted to propose the implementation strategies of green care for three communities, respectively, including human resource, volunteer or tourist management, revenue distribution, and marketing.

  相似文献   
987.
Smoking and Candida albicans (Calbicans) infection are risk factors for many oral diseases. Several studies have reported a close relationship between smoking and the occurrence of Calbicans infection. However, the exact underlying mechanism of this relationship remains unclear. We established a rat infection model and a C. albicans-Leuk1 epithelial cell co-culture model with and without smoke exposure to investigate the mechanism by which smoking contributes to Calbicans infection. Oral mucosa samples from healthy individuals and patients with oral leucoplakia were also analysed according to their smoking status. Our results indicated that smoking induced oxidative stress and redox dysfunction in the oral mucosa. Smoking-induced Nrf2 negatively regulated the NLRP3 inflammasome, impaired the oral mucosal defence response and increased the oral mucosa susceptibility to Calbicans. The results suggest that the Nrf2 pathway could be involved in the pathogenesis of oral diseases by mediating an antioxidative response to cigarette smoke exposure and suppressing host immunity against Calbicans.  相似文献   
988.
989.
990.
International Journal of Peptide Research and Therapeutics - Multidrug resistance (MDR) is one of the major obstacles to efficient chemotherapy against cancers, resulting from the overexpression of...  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