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   562篇
  免费   37篇
  国内免费   16篇
耳鼻咽喉   8篇
儿科学   18篇
妇产科学   6篇
基础医学   49篇
口腔科学   7篇
临床医学   62篇
内科学   127篇
皮肤病学   10篇
神经病学   7篇
特种医学   78篇
外科学   147篇
综合类   11篇
预防医学   20篇
眼科学   2篇
药学   41篇
肿瘤学   22篇
  2020年   5篇
  2019年   3篇
  2018年   6篇
  2017年   8篇
  2016年   11篇
  2015年   9篇
  2014年   12篇
  2013年   12篇
  2012年   15篇
  2011年   17篇
  2010年   13篇
  2009年   11篇
  2008年   11篇
  2007年   24篇
  2006年   11篇
  2005年   22篇
  2004年   19篇
  2003年   15篇
  2002年   12篇
  2001年   14篇
  2000年   12篇
  1999年   10篇
  1998年   17篇
  1997年   23篇
  1996年   26篇
  1995年   23篇
  1994年   23篇
  1993年   16篇
  1992年   13篇
  1991年   18篇
  1990年   19篇
  1989年   27篇
  1988年   14篇
  1987年   14篇
  1986年   8篇
  1985年   8篇
  1984年   6篇
  1983年   5篇
  1982年   8篇
  1981年   6篇
  1979年   7篇
  1978年   6篇
  1977年   5篇
  1976年   5篇
  1975年   10篇
  1974年   3篇
  1973年   6篇
  1970年   3篇
  1968年   3篇
  1967年   3篇
排序方式: 共有615条查询结果,搜索用时 15 毫秒
21.
22.

Objective

To determine conditional recurrence-free survival (RFS) and progression-free survival (PFS) and improve decision-making toward surveillance protocols and scheduling. Furthermore, evaluating the evolution of predictors for disease recurrence over time, because TaG1 non–muscle-invasive bladder cancer harbors a risk of disease recurrence and progression.

Material and methods

The retrospective multicenter design study includes 1,245 TaG1 bladder cancer patients with median follow-up of 62.7 (interquartile range: 34.3–91.1) months. Conditional RFS and PFS estimates were calculated using the Kaplan-Meier method. Multivariable Cox regression model was calculated proportional for the prediction of recurrence and progression (covariables: age, tumor size, multiple tumors, prior recurrence, and immediate postoperative instillation of chemotherapy).

Results

After 3 months without event, the conditional RFS and PFS (to ≥pT2) rates for 5 additional years without event were 57.5% and 93.4%, respectively. Given a 1-, 2-, 3-, and 5-year survival, the conditional RFS rates for 5 additional years without event improved by +9.8 (67.3%), +5.2 (72.5%), +6.5 (79.0%), +2.0 (81.0%), and +1.0% (82.0%), respectively. In contrast, the 5-year conditional PFS rates were more or less stable with 94.3% after 1 year to 94.1% after 5 years. Multivariable analyses showed decreasing impact of risk parameters on RFS estimates over time. Based on these findings, we suggest a risk stratification to individualize follow-up for intermediate risk TaG1. Main limitation was the retrospective design.

Conclusions

Conditional-survival analyses demonstrates that the patient risk profile changes over time. RFS rates rise with increasing survival whereas PFS rates were stable. The impact of prognostic features decreases over time. Our findings can be used for patient counseling and planning of personalized follow-up.  相似文献   
23.
24.
从绵毛马兜铃(Aristolocha mannisima Hance)中分得一个马兜铃酸倍半萜的酯类化合物,经红外、紫外、高分辩质谱和多种一维和二维核磁共振谱鉴定,确定了其骨架结构及顺反构型,命名为马兜铃酸萜酯I。  相似文献   
25.
26.
Many kidneys obtained from cadaver donors undergoing sudden cardiac arrest cannot be transplanted due to the long periods of warm ischemia from the moment of arrest to nephrectomy. A double-ballon-triple-lumen catheter for the rapid in situ preservation of cadaver kidneys has been designed. Used in combination with equipment routinely found in any hospital, it can cool human kidneys in situ to 10-15 C and maintain this temperature until nephrectomy can be performed. Kidenys preserved with this catheter have functioned after transplantation into suitable recipients. This report describes the design and laboratory evaluation of this new device, its clinical effectiveness and technique of insertion.  相似文献   
27.
28.
Surgical management of tracheal trauma   总被引:1,自引:0,他引:1  
  相似文献   
29.
30.
INTRODUCTION: Previously, we reported an increase in interstitial collagen and total mast-cell numbers in heart failure versus normal myocardium. A secondary increase, primarily in chymase-negative mast cells, occurred following LVAD support compared to matched pre-LVAD tissue samples and was associated with a decrease in interstitial collagen and bFGF. To further elucidate the changes in interstitial collagen, we investigated the direct interaction between mast cells, isolated from failing myocardium with or without previous LVAD support, and human fibroblasts in a coculture model. Additionally, the expression of HSP-47, the pro-collagen-specific chaperone protein, was determined in the particular myocardium. MATERIALS AND METHODS: Myocardial tissue was obtained from 10 patients with end-stage dilated cardiomyopathy (DCM) at the time of transplantation. Five patients were transplanted following LVAD support, five patients without previous LVAD support. Mast cells were isolated according to a standard protocol, including collagenase digestion and cell separation. The isolated mast cells were co-cultured with human fibroblasts for 12 h, with or without stimulation of degranulation, and protein synthesis was measured by [(3)H]-proline incorporation. HSP-47 immunostaining was performed in the different myocardial samples and the positive cells were quantified. RESULTS: Stimulated mast cells isolated from DCM tissue (without previous LVAD support) caused a 92% increase in [(3)H]-proline incorporation and consequently in protein production in fibroblasts compared to mast-cell free culture (P < 0.01), while conversely stimulated mast cells isolated from LVAD supported myocardium decreased the [(3)H]-proline incorporation by 63% (P < 0.01) below baseline. Nonstimulated mast cells did not significantly alter the protein production over baseline. There was also a significant increase in the number of HSP-47-positive cells in DCM myocardium compared to normal (P < 0.01) and there was a shift toward normal after LVAD support (P < 0.01). CONCLUSION: We demonstrate that fibroblast protein production in vitro is significantly altered by mast cells and that the direction of change is dependent on whether myocardium was supported by LVAD. We suggest that under long-term LVAD support there is a phenotypic alteration in myocardial mast cells, which leads to a change in concentration and/or composition of mediators, capable of re-remodeling the myocardial matrix.  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