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   344篇
  免费   21篇
  国内免费   6篇
耳鼻咽喉   17篇
儿科学   11篇
妇产科学   9篇
基础医学   34篇
口腔科学   7篇
临床医学   73篇
内科学   43篇
皮肤病学   8篇
神经病学   33篇
特种医学   5篇
外科学   95篇
综合类   3篇
预防医学   7篇
眼科学   4篇
药学   11篇
肿瘤学   11篇
  2023年   3篇
  2022年   3篇
  2021年   6篇
  2020年   7篇
  2019年   7篇
  2018年   11篇
  2017年   12篇
  2016年   15篇
  2015年   12篇
  2014年   16篇
  2013年   23篇
  2012年   26篇
  2011年   27篇
  2010年   20篇
  2009年   20篇
  2008年   20篇
  2007年   28篇
  2006年   22篇
  2005年   21篇
  2004年   12篇
  2003年   12篇
  2002年   11篇
  2001年   5篇
  2000年   5篇
  1999年   5篇
  1998年   4篇
  1997年   4篇
  1996年   1篇
  1995年   2篇
  1994年   3篇
  1993年   1篇
  1992年   3篇
  1991年   3篇
  1989年   1篇
排序方式: 共有371条查询结果,搜索用时 937 毫秒
1.
2.
Interleukin-18 is predominantly a macrophage-derived cytokine with a key role in inflammation and cell-mediated immunity. Having previously demonstrated IL-18 upregulation in a rat model of kidney rejection, here we examined IL-18 in a fully MHC-mismatched murine model of acute kidney rejection using IL-18-deficient recipients (IL-18-/-) and animals administered neutralizing IL-18 binding protein (IL-18BP). Gene expression of IL-18 and its receptor were significantly upregulated in allografts compared to isografts, as was the cellular infiltrate (T cells and macrophages) (p < 0.001). Allografts developed kidney dysfunction (p < 0.05) and tubulitis (p < 0.01) not observed in controls. There was a significant reduction in gene expression of IL-18 downstream pro-inflammatory molecules (iNOS, TNFalpha and IFNgamma) in IL-18-/- recipients (p < 0.01), and IL-18BP-treated animals. The CD4+ infiltrate and IL-4 mRNA expression was greater in the IL-18-/- recipients than wild-type (WT) allografts and IL-18BP-treated animals (p < 0.05), suggesting a Th2-bias which was supported by IFNgamma and IL-4 ELISPOT data and an increased eosinophil accumulation (p < 0.001). Neither IL-18 deficiency nor neutralization prevented renal dysfunction or tubulitis. This study demonstrates increased production of IL-18 in murine kidney allograft rejection and provides evidence that IL-18-induced pathways of inflammation are active. However, neither IL-18 deficiency nor neutralization was protective against the development of allograft rejection.  相似文献   
3.
4.
5.
BACKGROUND: Chronic renal allograft rejection is characterized by interstitial fibrosis and vasculopathy. Vascular endothelial growth factor (VEGF) is an endothelial mitogen with increased expression in inflammation and vasculopathy. METHODS: Renal tissue from 17 patients with chronic rejection was examined for VEGF protein and the presence of CD 68-positive macrophages, and compared to biopsies from patients with temporary allograft dysfunction, acute rejection, and native kidneys with thin membrane disease. RESULTS: In the chronic rejection group, there was markedly increased expression of VEGF protein in the interstitium (P<0.0001). In serial sections, VEGF colocalized with the expression of CD 68-positive macrophages. Significantly more macrophages were in the tubulointerstitium in tissue with chronic rejection than in those with temporary allograft dysfunction (P<0.005). Additionally, VEGF protein expression in the glomeruli and the vascular compartment of patients with chronic rejection was increased. CONCLUSION: The up-regulation of VEGF in chronic renal allograft rejection may be important in inflammation and development of fibrosis.  相似文献   
6.
This study investigates the gross anatomy of the original and the regenerated tail in the green anole (Anolis carolinensis). Dissections were conducted on 24 original and 13 regenerated tails. While the extrinsic muscles of the original tail in A. carolinensis are similar to those in other known Anolis lizard species, the extent of the origins of m. caudofemoralis longus and m. caudofemoralis brevis is more restricted. These differences may underlie variation in locomotor performance among anole ecomorphs. The intrinsic muscles of the original tail are also described, confirming previous findings and documenting new details, including muscle origins and insertions and the range of intraspecific variation. A comparison of the intrinsic muscles of the original tail and the regenerated tail muscles reveals key differences, such as the lack of interdigitating muscle segments and intramuscular septa in the regenerated tail. These findings, along with the replacement of interlocking vertebrae with a stiff, cartilaginous rod, suggest that important functional differences exist between the original and regenerated tail. In particular, the regenerated tail is predicted to be less capable of coordinated, fine movements. Studies of the physical properties and range of motion of the original and regenerated tail are required to test this hypothesis. This atlas of tail anatomy in A. carolinensis represents a key resource for developmental and genetic studies of tail regeneration in lizards, as well as studies of anole evolution and biomechanics. Anat Rec,, 2012. © 2012 Wiley Periodicals, Inc.  相似文献   
7.
We explored the association between the activities of antioxidant enzymes and their metallic cofactors in rats treated with cisplatin. The antioxidant effects of aminoguanidine, and a combination of vitamins E and C were investigated. Plasma platin was significantly lower than liver and kidney. Cisplatin treatment caused significant increase in plasma Se-glutathione peroxidase activity. Activities of Se-glutathione peroxidase, glutathione S-transferase, catalase and Cu,Zn-superoxide dismutase have been found to be significantly decreased in liver and kidney compared to controls. Zn levels in these organs were diminished upon cisplatin treatment, while levels of Cu were unaffected. Interestingly, levels of iron, the cofactor of catalase, were found to be significantly increased in liver and kidney. Intervention with aminoguanidine or vitamins was generally prevented cisplatin-caused changes in the activity of enzymes and in the tissue levels of cofactor metals. These observations suggest that relation between activities of enzymes and levels of cofactor metals is multifactorial.  相似文献   
8.
The aim of this study was to compare the effectiveness of antioxidants including cysteamine (2.5, 7.5 mm ), hyaluronan (0.25, 1 mg ml?1) and fetuin (5, 10 mg ml?1) in the freezing of Brown Swiss bull semen. The best percentages of CASA motilities were achieved with 10 mg ml?1 of fetuin and 2.5 mm of cysteamine. For sperm morphology, 10 mg ml?1 of fetuin and 2.5 mm of cysteamine had better protective effects (P < 0.001). The results of hypo‐osmotic swelling test showed that the percentage values of membrane integrity in all the groups, excluding that supplemented with 5 mg ml?1 of fetuin, were higher than those of the control group (P < 0.001). Results obtained for the DNA damage of sperm cells demonstrated that 0.25 mg ml?1 of hyaluronan, and 2.5 and 7.5 mm of cysteamine led to lower rates of spermatozoa with damaged DNA, compared with the control group (P < 0.001). The maintenance of superoxide dismutase and glutathione peroxidase antioxidant activities following freeze‐thawing with 2.5 and 7.5 mm of cysteamine and 10 mg ml?1 of fetuin was demonstrated to be at a higher level in comparison with the control group (P < 0.001). Malondialdehyde formation was found to be lower in the groups supplemented with 0.25 mg ml?1 of hyaluronan and 7.5 mm of cysteamine after the freeze‐thawing process (P < 0.001).  相似文献   
9.
10.
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