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   29131篇
  免费   2128篇
  国内免费   1613篇
  32872篇
  2024年   64篇
  2023年   345篇
  2022年   830篇
  2021年   1405篇
  2020年   962篇
  2019年   1188篇
  2018年   1167篇
  2017年   828篇
  2016年   1229篇
  2015年   1896篇
  2014年   2125篇
  2013年   2286篇
  2012年   2614篇
  2011年   2288篇
  2010年   1452篇
  2009年   1234篇
  2008年   1511篇
  2007年   1328篇
  2006年   1165篇
  2005年   979篇
  2004年   790篇
  2003年   695篇
  2002年   533篇
  2001年   479篇
  2000年   379篇
  1999年   411篇
  1998年   243篇
  1997年   266篇
  1996年   252篇
  1995年   214篇
  1994年   217篇
  1993年   150篇
  1992年   216篇
  1991年   184篇
  1990年   130篇
  1989年   106篇
  1988年   79篇
  1987年   108篇
  1986年   82篇
  1985年   69篇
  1984年   52篇
  1983年   36篇
  1982年   36篇
  1981年   26篇
  1980年   21篇
  1979年   25篇
  1978年   17篇
  1975年   21篇
  1974年   18篇
  1972年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
The transformation of 6-keto-PGF to two prostacyclin metabolites, 2,3-dinor-6-keto-PGF (I) and 2,3-dinor-6,15-diketo-13,14-dihydro-PGF (II) by Mycobacterium rhodochrous UC-6176 is described. The finding that the bacterium oxidized 6-keto-PGF to the 6,15-diketo metabolite II shows that it contains 15-hydroxy prostaglandin dehydrogenase and Δ13 reductase enzyme systems.  相似文献   
32.
33.
Schistosomiasis is a serious and widespread parasitic disease caused by infection with Schistosoma. Because the parasite’s eggs are primarily responsible for schistosomiasis dissemination and pathogenesis, inhibiting egg production is a potential approach to control the spread and severity of the disease. The bromodomain and extra-terminal (BET) proteins represent promising targets for the development of epigenetic drugs against Schistosoma. JQ-1 is a selective inhibitor of the BET protein family. In the present study, JQ-1 was applied to S. japonicum in vitro. By using laser confocal scanning microscopy and EdU incorporation assays, we showed that application of JQ-1 to worms in vitro affected egg laying and the development of both the male and female reproductive systems. JQ-1 also inhibited the expression of the reproductive-related genes SjPlk1 and SjNanos1 in S. japonicum. Mice infected with S. japonicum were treated with JQ-1 during egg granuloma formation. JQ-1 treatment significantly reduced the size of the liver granulomas and levels of serum alanine aminotransferase and aspartate aminotransferase in mice and suppressed both egg laying and the development of male and female S. japonicum reproductive systems in vivo. Moreover, the mRNA expression levels of some proinflammatory cytokines were decreased in the parasites. Our findings suggest that JQ-1 treatment attenuates S. japonicum egg–induced hepatic granuloma due at least in part to suppressing the development of the reproductive system and egg production of S. japonicum. These findings further suggest that JQ-1 or other BET inhibitors warrant additional study as a new approach for the treatment or prevention of schistosomiasis.  相似文献   
34.
Aging is a major risk factor for many diseases,especially in highly prevalent cardiopulmonary comorbidities and infectious diseases including Coronavirus Diseas...  相似文献   
35.
36.
37.
38.
Thoracic ossification of the ligamentum flavum (TOLF) is ectopic ossification of the spinal ligaments. Histologically, the development of TOLF can be described as the process of endochondral ossification. However, the underlying aetiology has not been completely clarified. In this investigation, the gene expression profile associated with leucine‐rich repeat‐containing G‐protein‐coupled receptors (LGR) and Wnt signalling pathway in the thoracic ligamentum flavum cells (TLFCs) of different ossification stages was analysed via RNA sequencing. We further confirmed the significant differences in the related gene expression profile by Gene Ontology (GO) enrichment analysis. LGR5 was first identified in primary human TLFCs during osteogenic differentiation. To evaluate the effect of LGR5 on osteogenic differentiation, LGR5 has been knocked down and overexpressed in human TLFCs. We observed that the knockdown of LGR5 inhibited the activity of Wnt signalling and attenuated the potential osteogenic differentiation of TLFCs, while overexpression of LGR5 activated the Wnt signalling pathway and increased osteogenic differentiation. Our results provide important evidence for the potent positive mediatory effects of LGR5 on osteogenesis by enhancing the Wnt signalling pathway in TOLF.  相似文献   
39.
40.
Autologous adipose tissue is an ideal soft tissue filling material, and its biocompatibility is better than that of artificial tissue substitutes, foreign bodies and heterogeneous materials. Although autologous fat transplantation has many advantages, the low retention rate of adipose tissue limits its clinical application. Here, we identified a secretory glycoprotein, leucine‐rich‐alpha‐2‐glycoprotein 1 (LRG‐1), that could promote fat graft survival through RAB31‐mediated inhibition of hypoxia‐induced apoptosis. We showed that LRG‐1 injection significantly increased the maintenance of fat volume and weight compared with the control. In addition, higher fat integrity, more viable adipocytes and fewer apoptotic cells were observed in the LRG‐1‐treated groups. Furthermore, we discovered that LRG‐1 could reduce the ADSC apoptosis induced by hypoxic conditions. The mechanism underlying the LRG‐1‐mediated suppression of the ADSC apoptosis induced by hypoxia was mediated by the upregulation of RAB31 expression. Using LRG‐1 for fat grafts may prove to be clinically successful for increasing the retention rate of transplanted fat.  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