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   457438篇
  免费   41303篇
  国内免费   30444篇
耳鼻咽喉   3770篇
儿科学   6148篇
妇产科学   6222篇
基础医学   50752篇
口腔科学   7718篇
临床医学   63784篇
内科学   63676篇
皮肤病学   4835篇
神经病学   22614篇
特种医学   16524篇
外国民族医学   257篇
外科学   42153篇
综合类   81620篇
现状与发展   99篇
一般理论   48篇
预防医学   32382篇
眼科学   12889篇
药学   49221篇
  470篇
中国医学   28202篇
肿瘤学   35801篇
  2024年   1447篇
  2023年   6421篇
  2022年   16944篇
  2021年   21569篇
  2020年   16788篇
  2019年   13910篇
  2018年   14671篇
  2017年   13831篇
  2016年   12832篇
  2015年   19980篇
  2014年   25053篇
  2013年   22918篇
  2012年   34097篇
  2011年   38237篇
  2010年   25443篇
  2009年   20593篇
  2008年   25651篇
  2007年   25625篇
  2006年   24656篇
  2005年   23912篇
  2004年   15947篇
  2003年   15163篇
  2002年   12584篇
  2001年   10709篇
  2000年   10621篇
  1999年   10732篇
  1998年   6650篇
  1997年   6364篇
  1996年   5082篇
  1995年   4732篇
  1994年   3991篇
  1993年   2579篇
  1992年   3329篇
  1991年   2848篇
  1990年   2422篇
  1989年   2101篇
  1988年   1818篇
  1987年   1655篇
  1986年   1351篇
  1985年   972篇
  1984年   563篇
  1983年   422篇
  1982年   226篇
  1981年   254篇
  1980年   196篇
  1979年   268篇
  1978年   126篇
  1977年   109篇
  1976年   78篇
  1974年   86篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Abstract

Background

Comorbidities are commonly seen in patients with coronavirus disease 2019 (COVID-19), but the clinical implication is not yet well-delineated. We aim to characterize the prevalence and clinical implications of comorbidities in patients with COVID-19.  相似文献   
72.
73.
74.
Ferroptosis is an iron-dependent novel cell death pathway. Deferoxamine, a ferroptosis inhibitor, has been reported to promote spinal cord injury repair. It has yet to be clarified whether ferroptosis inhibition represents the mechanism of action of Deferoxamine on spinal cord injury recovery. A rat model of Deferoxamine at thoracic 10 segment was established using a modified Allen's method. Ninety 8-week-old female Wistar rats were used. Rats in the Deferoxamine group were intraperitoneally injected with 100 mg/kg Deferoxamine 30 minutes before injury. Simultaneously, the Sham and Deferoxamine groups served as controls. Drug administration was conducted for 7 consecutive days. The results were as follows:(1) Electron microscopy revealed shrunken mitochondria in the spinal cord injury group.(2) The Basso, Beattie and Bresnahan locomotor rating score showed that recovery of the hindlimb was remarkably better in the Deferoxamine group than in the spinal cord injury group.(3) The iron concentration was lower in the Deferoxamine group than in the spinal cord injury group after injury.(4) Western blot assay revealed that, compared with the spinal cord injury group, GPX4, xCT, and glutathione expression was markedly increased in the Deferoxamine group.(5) Real-time polymerase chain reaction revealed that, compared with the Deferoxamine group, mRNA levels of ferroptosis-related genes Acyl-CoA synthetase family member 2(ACSF2) and iron-responsive element-binding protein 2(IREB2) were up-regulated in the Deferoxamine group.(6) Deferoxamine increased survival of neurons and inhibited gliosis. These findings confirm that Deferoxamine can repair spinal cord injury by inhibiting ferroptosis. Targeting ferroptosis is therefore a promising therapeutic approach for spinal cord injury.  相似文献   
75.
Canadian Journal of Anesthesia/Journal canadien d'anesthésie - To assess the management and safety of epidural or general anesthesia for Cesarean delivery in parturients with coronavirus...  相似文献   
76.
77.
78.
Mammalian spermatogenesis is a well-organized process of cell development and differentiation. Meiosis expressed gene 1 (MEIG1) plays an essential role in the regulation of spermiogenesis. To explore potential mechanisms of MEIG1''s action, a yeast two-hybrid screen was conducted, and several potential binding partners were identified; one of them was membrane occupation and recognition nexus repeat containing 3 (MORN3). MORN3 mRNA is only abundant in mouse testis. In the testis, Morn3 mRNA is highly expressed in the spermiogenesis stage. Specific anti-MORN3 polyclonal antibody was generated against N-terminus of the full-length MORN3 protein, and MORN3 expression and localization was examined in vitro and in vivo. In transfected Chinese hamster ovary cells, the antibody specifically crossed-reacted the full-length MORN3 protein, and immunofluorescence staining revealed that MORN3 was localized throughout the cytoplasm. Among multiple mouse tissues, about 25 kDa protein, was identified only in the testis. The protein was highly expressed after day 20 of birth. Immunofluorescence staining on mixed testicular cells isolated from adult wild-type mice demonstrated that MORN3 was expressed in the acrosome in germ cells throughout spermiogenesis. The protein was also present in the manchette of elongating spermatids. The total MORN3 expression and acrosome localization were not changed in the Meig 1-deficient mice. However, its expression in manchette was dramatically reduced in the mutant mice. Our studies suggest that MORN3 is another regulator for spermatogenesis, probably together with MEIG1.  相似文献   
79.
80.
Abstract

Oxidative stress (OS) has been proposed to play a role in the development of EMs. Peroxiredoxins are a family of antioxidant proteins that exhibit peroxidase activity in a thioredoxin-dependent manner, protecting cells against OS. The Western blotting results showed that the relative expression of PRDX4 was significantly increased in ectopic endometria compared with the normal endometria of EMs-free (p?<?.05). The H2O2 concentration was also significantly higher in the ectopic endometrium. PRDX4 siRNA was transfected into primary ectopic endometrial stromal cells (EESCs). The viability of the transfected EESCs was measured by CCK-8 assay, and the results showed significantly decreased cell viability. Furthermore, the apoptosis rate and ROS generation in flow cytometry assays were significantly increased after the knockdown of PRDX4 expression (p?<?.05). Scratch assays and transwell assays revealed that decreased expression of PRDX4 mediated by siRNA inhibited EESC migration and invasion. In conclusion, these findings indicate the potential role of PRDX4 in the development of EMs and PRDX4 as a possible therapeutic target for EMs treatment.  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