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   1746篇
  免费   51篇
  国内免费   15篇
耳鼻咽喉   24篇
儿科学   132篇
妇产科学   61篇
基础医学   121篇
口腔科学   61篇
临床医学   128篇
内科学   331篇
皮肤病学   36篇
神经病学   140篇
特种医学   113篇
外科学   399篇
综合类   11篇
预防医学   40篇
眼科学   85篇
药学   71篇
肿瘤学   59篇
  2024年   1篇
  2023年   12篇
  2022年   21篇
  2021年   24篇
  2020年   16篇
  2019年   15篇
  2018年   18篇
  2017年   29篇
  2016年   52篇
  2015年   52篇
  2014年   60篇
  2013年   114篇
  2012年   132篇
  2011年   150篇
  2010年   75篇
  2009年   69篇
  2008年   144篇
  2007年   172篇
  2006年   155篇
  2005年   147篇
  2004年   110篇
  2003年   68篇
  2002年   58篇
  2001年   27篇
  2000年   14篇
  1999年   14篇
  1998年   7篇
  1997年   7篇
  1996年   4篇
  1995年   4篇
  1994年   5篇
  1993年   3篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   6篇
  1985年   10篇
  1983年   2篇
  1982年   2篇
  1981年   1篇
  1980年   1篇
  1973年   2篇
  1970年   1篇
排序方式: 共有1812条查询结果,搜索用时 0 毫秒
21.
22.
Human kallikreins (hKs) have been reported to be involved in human cancers, and several hKs are promising biomarkers of various cancers, such as prostate, ovarian, breast, and testicular cancer. In the present study, we aimed to evaluate the prognostic value of immunohistochemical expression of hK11 in patients with gastric cancer. The study included 55 (36 men and 19 women; 58 ± 10 years of mean age) patients with gastric cancer treated with surgery and adjuvant chemoradiotherapy. Tissue sections were evaluated immunohistochemically with a monoclonal anti-hK11 antibody. Of the 55 patients, 35 (63.6%) were hK11-positive and 20 (36.4%) were hK11-negative. Disease-free and overall survival rates were significantly higher in patients with hK11 positive than in those with hK-11 negative expression (24 months vs. 11 months, p: 0.043; 29 months vs. 13 months, p: 0.038, respectively). In conclusion, hK11 expression in gastric cancer appears to be associated with a better prognosis. hK11 may be a prognostic biomarker of gastric cancer. On the other hand, it is needed to elucidate the mechanisms underlying the regulation of hK11 expression in gastric cancer.  相似文献   
23.
24.
25.
26.
Image quality in non‐contrast‐enhanced (NCE) angiograms is often limited by scan time constraints. An effective solution is to undersample angiographic acquisitions and to recover vessel images with penalized reconstructions. However, conventional methods leverage penalty terms with uniform spatial weighting, which typically yield insufficient suppression of aliasing interference and suboptimal blood/background contrast. Here we propose a two‐stage strategy where a tractographic segmentation is employed to auto‐extract vasculature maps from undersampled data. These maps are then used to incur spatially adaptive sparsity penalties on vascular and background regions. In vivo steady‐state free precession angiograms were acquired in the hand, lower leg and foot. Compared with regular non‐adaptive compressed sensing (CS) reconstructions (CSlow), the proposed strategy improves blood/background contrast by 71.3 ± 28.9% in the hand (mean ± s.d. across acceleration factors 1–8), 30.6 ± 11.3% in the lower leg and 28.1 ± 7.0% in the foot (signed‐rank test, P < 0.05 at each acceleration). The proposed targeted reconstruction can relax trade‐offs between image contrast, resolution and scan efficiency without compromising vessel depiction. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   
27.
Imaging has become a pivotal component throughout a patient's encounter with cancer, from initial disease detection and characterization through treatment response assessment and posttreatment follow‐up. Recent progress in imaging technology has presented new opportunities for improving clinical care. This article provides updates on the latest approaches to imaging of 5 common cancers: breast, lung, prostate, and colorectal cancers, and lymphoma. CA Cancer J Clin 2012. © 2012 American Cancer Society.  相似文献   
28.
Our aim was to investigate, in patients with heart failure, the relationship between left atrial size and exercise capacity and cardiovascular events. Seventy-five patients (67 men and 8 women; mean age, 53.4 +/- 8.8 yr) with left ventricular ejection fractions of < or =0.45 (New York Heart Association functional classes I-III) were matched by age and sex with 20 healthy control subjects. Echocardiographic examinations were performed, as was exercise testing by the modified Bruce protocol. Patients were monitored for a period of 330 to 480 days for cardiac death or for heart failure that required hospitalization. The indexed left atrial diastolic size (beta level = -0.534, P <0.001) and left ventricular late diastolic filling velocity (beta level = 0.247, P <0.017) were the most important values in predicting low exercise capacity. The only independent predictor of low exercise capacity (<5 METS) was the indexed left atrial diastolic size (odds ratio, 1.428; 95% confidence interval, 1.09-1.702; P <0.001). Every 1 mm/m2 increase in indexed left atrial diastolic dimension caused a 42.8% increase in the risk of severe heart failure (exercise capacity, <5 METS). Independent predictors for cardiovascular events were indexed as left atrial systolic size (odds ratio, 1.383; 95% confidence interval, 1.145-1.671; P <0.001) and left ventricular early diastolic/late diastolic filling velocity (odds ratio, 1.096; 95% confidence interval, 1.010-1.189; P <0.027). Indexed left atrial diastolic and left atrial systolic size predict exercise capacity and cardiovascular events, respectively, in New York Heart Association functional class I through III heart failure patients.  相似文献   
29.
We aimed to obtain gamma amanitin with high purity through a purification process and compare toxic effects of alpha, beta, and gamma amanitin. Specific concentrations of the toxins (25, 10, 1, and 0.1?μg/mL) were applied to the C3A human hepatocytes. A MTT test was performed to determine the level of toxicity. Alpha amanitin showed a higher toxicity in 48?h while the lowest toxicity was observed in beta amanitin. The toxicity level of gamma amanitin was found between the alpha and beta amanitin toxicity. Our method is suitable for obtaining gamma amanitin with high purity (>99%) as well as for obtaining alpha amanitin and beta amanitin. Gamma amanitin has been shown to have equal responsibility for toxicity as alpha amanitin in amanita poisoning.  相似文献   
30.
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