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   55566篇
  免费   6654篇
  国内免费   22331篇
  84551篇
  2024年   542篇
  2023年   1538篇
  2022年   2696篇
  2021年   3316篇
  2020年   2879篇
  2019年   3235篇
  2018年   2488篇
  2017年   2193篇
  2016年   2580篇
  2015年   3729篇
  2014年   4814篇
  2013年   4488篇
  2012年   5982篇
  2011年   5656篇
  2010年   4220篇
  2009年   4197篇
  2008年   4615篇
  2007年   4277篇
  2006年   3913篇
  2005年   3248篇
  2004年   2577篇
  2003年   2156篇
  2002年   1906篇
  2001年   1632篇
  2000年   1514篇
  1999年   994篇
  1998年   566篇
  1997年   333篇
  1996年   303篇
  1995年   253篇
  1994年   221篇
  1993年   153篇
  1992年   146篇
  1991年   147篇
  1990年   119篇
  1989年   120篇
  1988年   100篇
  1987年   78篇
  1986年   65篇
  1985年   82篇
  1984年   50篇
  1983年   62篇
  1982年   70篇
  1981年   36篇
  1978年   16篇
  1958年   21篇
  1957年   19篇
  1955年   16篇
  1954年   19篇
  1950年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Xiao  Na  Zhang  Jun  Chen  Chao  Wan  Yanfang  Wang  Ning  Yang  Jing 《Mammalian genome》2019,30(9-10):276-288
Mammalian Genome - Increasing evidence shows that miRNAs play pivotal roles in cardiovascular diseases, including heart failure (HF). The aim of this study was to investigate the role of miR-129-5p...  相似文献   
992.
993.
994.
995.
996.
997.
ABSTRACT

Smog pollution has received widely attention in recent years due to its negative effects. There is consensus that the motor vehicle exhaust emission is one of the sources of smog pollution and reduced private car use would significantly improve the air quality and alleviate the smog pollution problem. In this research, we aim to investigate how public smog knowledge and risk perception (physical health risk perception and mental health risk perception) affect public attitude and intention to reduce car use. A questionnaire survey of 334 randomly sampled respondents was designed to test these relationships. The results show that public smog knowledge is positively and significantly related to physical health risk perception, mental health risk perception, attitude and intention to reduce car use. Public smog knowledge has the largest impact on intention to reduce car use. Furthermore, physical health risk perception and mental health risk perception are positively and significantly associated with attitude and intention to reduce car use. In addition, the results also indicated that public smog knowledge is at a low level. Based on the results, implications and suggestions for future research were discussed.  相似文献   
998.
Journal of Industrial Microbiology & Biotechnology - In this work, we found that the Lrp/AsnC family protein SACE_5717 negatively regulated erythromycin biosynthesis in S. erythraea. Disruption...  相似文献   
999.
Brucella melitensis infection causes acute necrotizing inflammation in pregnant animals; however, the pathophysiological mechanisms leading to placentitis are unknown. Here, we demonstrate that high‐mobility group box 1 (HMGB1) acts as a mediator of placenta inflammation in Bmelitensis‐infected pregnant mice model. HMGB1 levels were increased in trophoblasts or placental explant during B. melitensis infection. Inhibition of HMGB1 activity with neutralising antibody significantly reduced the secretion of inflammatory cytokines in B. melitensis‐infected trophoblasts or placenta, whereas administration of recombinant HMGB1 (rHMGB1) increased the inflammatory response. Mechanistically, this decreased inflammatory response results from inhibition of HMGB1 activity, which cause the suppression of both mitogen‐activated protein kinases and nuclear factor kappa‐light‐chain‐enhancer of activated B cells (NF‐κB) activation. Moreover, neutralising antibody to HMGB1 prevented B. melitensis infection‐induced activation of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase in trophoblasts. In contrast, in vitro stimulation of trophoblasts with rHMGB1 caused activation of NADPH oxidase and increased the production of ROS, which contributes to high bacterial burden within trophoblasts or placenta. In vivo, treatment with anti‐HMGB1 antibody increases the number of Brucella survival within placenta in B. melitensis‐infected pregnant mice but successfully reduced the severity of placentitis and abortion.  相似文献   
1000.
Li  Yun  Liu  Le  Cui  Suzhen  Chen  Feizhou 《Limnology》2019,20(2):191-201
Limnology - External nutrient loading has a major influence on the abundance, composition and diversity of zooplankton communities. To clarify how the reduction of nutrient loading during lake...  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