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   812篇
  免费   28篇
  国内免费   4篇
耳鼻咽喉   6篇
儿科学   42篇
妇产科学   22篇
基础医学   55篇
口腔科学   51篇
临床医学   61篇
内科学   175篇
皮肤病学   36篇
神经病学   63篇
特种医学   51篇
外科学   162篇
综合类   12篇
预防医学   7篇
眼科学   41篇
药学   18篇
中国医学   10篇
肿瘤学   32篇
  2024年   1篇
  2023年   1篇
  2022年   8篇
  2021年   9篇
  2020年   19篇
  2019年   10篇
  2018年   12篇
  2017年   17篇
  2016年   16篇
  2015年   29篇
  2014年   27篇
  2013年   53篇
  2012年   51篇
  2011年   56篇
  2010年   32篇
  2009年   34篇
  2008年   61篇
  2007年   84篇
  2006年   75篇
  2005年   63篇
  2004年   51篇
  2003年   40篇
  2002年   22篇
  2001年   6篇
  2000年   13篇
  1999年   5篇
  1998年   5篇
  1997年   10篇
  1996年   3篇
  1995年   3篇
  1994年   5篇
  1993年   1篇
  1992年   3篇
  1991年   1篇
  1990年   3篇
  1989年   1篇
  1988年   1篇
  1984年   2篇
  1983年   1篇
  1982年   1篇
  1981年   1篇
  1980年   4篇
  1979年   1篇
  1969年   1篇
  1967年   1篇
  1965年   1篇
排序方式: 共有844条查询结果,搜索用时 0 毫秒
11.
12.

PURPOSE

The objective of this study was to compare the light transmittance of zirconia in different thicknesses using various light curing units.

MATERIALS AND METHODS

A total of 21 disc-shaped zirconia specimens (5 mm in diameter) in different thicknesses (0.3, 0.5 and 0.8 mm) were prepared. The light transmittance of the specimens under three different light-curing units (quartz tungsten halogen, light-emitting diodes and plasma arc) was compared by using a hand-held radiometer. Statistical significance was determined using two-way ANOVA (α=.05).

RESULTS

ANOVA revealed that thickness of zirconia and light curing unit had significant effects on light transmittance (P<.001).

CONCLUSION

Greater thickness of zirconia results in lower light transmittance. Light-emitting diodes light-curing units might be considered as effective as Plasma arc light-curing units or more effective than Quartz-tungsten-halogen light-curing units for polymerization of the resin-based materials.  相似文献   
13.
14.
Tekin G  Sivri N  Tekin YK  Topal E  Erbay AR  Yetkin E 《Angiology》2012,63(7):552-555
We assessed the clinical echocardiograhic, hematological, and biochemical parameters in patients with dilated cardiomyopathy (DCMP) and control individuals mainly focusing on the mean platelet volume (MPV) in terms of DCMP and left ventricle (LV) thrombus formation. Consecutive patients (n = 251) with DCMP and 266 patients without DCMP were studied. Mean platelet volume was significantly greater in patients with DCMP than in control patients (P < .05 for all comparisons). Comparing DCMP patients with LV thrombus (19 patients, 8%) and without LV thrombus (232 patients, 92%) showed that the prevalence of smokers was significantly higher and ejection fraction was significantly lower in patients with LV thrombus. We have shown that patients with DCMP have significantly higher MPV suggesting more platelet activation and the MPV of patients with DCMP and LV thrombus is comparable to those of patients without LV thrombus.  相似文献   
15.
16.
Obesity Surgery - This study aims to examine the predictive role of obesity-type-related indexes and perioperative intraabdominal pressure measurements for early postoperative complications...  相似文献   
17.
The aim of this study is to assess the biomechanical advantage of adding strut allograft and the effect of its position on the construct in Vancouver type B1 fractures. Fifteen forth-generation synthetic femurs were used and created a fracture model at the tip of prosthesis, and subsequently fixated with a lateral plate only, lateral plate and medial strut, lateral plate and anterior strut. Rotational and axial tests were performed. In all loading tests, the plate with medial strut group was stiffer than the other constructs and had higher failure load values and had less displacement in the fracture site. A combination of a plate with a medial strut allograft provides more mechanical stability on periprosthetic femoral fractures near the tip of a total hip arthroplasty.  相似文献   
18.
BackgroundInternalized stigma, adoption of negative attitudes and stereotypes of the society regarding persons'' illness, has not been studied previously in pediatric psoriasis patients.ObjectiveWe aimed to investigate the internalized stigma in pediatric psoriasis patients and to determine differences according to factors affecting internalized stigma compared to adult psoriasis patients.MethodsThis multicenter, cross-sectional, comparative study included 125 pediatric (55 female, 70 male; mean age±standard deviation [SD], 14.59±2.87 years) and 1,235 adult psoriasis patients (577 female, 658 male; mean age±SD, 43.3±13.7 years). Psoriasis Internalized Stigma Scale (PISS), Dermatology Life Quality Index (DLQI), Perceived Health Status (PHS), and the General Health Questionnaire (GHQ)-12 were the scales used in the study.ResultsThe mean PISS was 58.48±14.9 in pediatric group. When PISS subscales of groups were compared, the pediatric group had significantly higher stigma resistance (p=0.01) whereas adult group had higher scores of alienation (p=0.01) and stereotype endorsement (p=0.04). There was a strong correlation between mean values of PISS and DLQI (r=0.423, p=0.001). High internalized stigma scores had no relation to either the severity or localization of disease in pediatric group. However, poor PHS (p=0.007) and low-income levels (p=0.03) in both groups, and body mass index (r=0.181, p=0.04) in the pediatric group were related to high PISS scores.ConclusionInternalized stigma in pediatric patients is as high as adults and is related to poor quality of life, general health, and psychological illnesses. Unlike adults, internalized stigma was mainly determined by psoriasis per se, rather than disease severity or involvement of visible body parts, genitalia or folds.  相似文献   
19.
Macroautophagy (autophagy) is a regulated catabolic pathway to degrade cellular organelles and macromolecules. The role of autophagy in cancer is complex and may differ depending on tumor type or context. Here we show that pancreatic cancers have a distinct dependence on autophagy. Pancreatic cancer primary tumors and cell lines show elevated autophagy under basal conditions. Genetic or pharmacologic inhibition of autophagy leads to increased reactive oxygen species, elevated DNA damage, and a metabolic defect leading to decreased mitochondrial oxidative phosphorylation. Together, these ultimately result in significant growth suppression of pancreatic cancer cells in vitro. Most importantly, inhibition of autophagy by genetic means or chloroquine treatment leads to robust tumor regression and prolonged survival in pancreatic cancer xenografts and genetic mouse models. These results suggest that, unlike in other cancers where autophagy inhibition may synergize with chemotherapy or targeted agents by preventing the up-regulation of autophagy as a reactive survival mechanism, autophagy is actually required for tumorigenic growth of pancreatic cancers de novo, and drugs that inactivate this process may have a unique clinical utility in treating pancreatic cancers and other malignancies with a similar dependence on autophagy. As chloroquine and its derivatives are potent inhibitors of autophagy and have been used safely in human patients for decades for a variety of purposes, these results are immediately translatable to the treatment of pancreatic cancer patients, and provide a much needed, novel vantage point of attack.  相似文献   
20.
BACKGROUND: Diagnosis of tuberculous pleuritis is difficult because of its nonspecific clinical presentation and decreased efficiency of traditional diagnostic methods. We investigated the use of procalcitonin (PCT) concentration in tuberculous pleuritis diagnosis. METHODS: A prospective clinical study was performed with two different patient groups. A total of 28 patients were included: 18 with tuberculosis and 10 with nontuberculous pleurisy. Serum and pleural fluid PCT concentrations were evaluated before treatment. RESULTS: Serum and pleural fluid PCT concentrations were statistically different between tuberculous and nontuberculous pleurisy groups (P = 0.012 and P = 0.004, respectively), even though they were not elevated in relation to the cut-off level of 0.5 ng/mL. A positive and significant correlation was detected between serum and pleural fluid PCT levels (r = 0.49, P = 0.008). Diagnostic specificity and sensitivity values for serum and pleural fluid PCT in discriminating tuberculous from nontuberculous pleurisy were 80% and 72.2%, and 90% and 66.7% at the 0.081 and 0.113 ng/mL cut-off values, respectively. CONCLUSION: Relative to the current cut-off level of 0.5 ng/mL, PCT concentration is not a useful parameter for the diagnosis of tuberculous pleurisy. Because there were PCT levels in patients with tuberculous pleurisy that were below the current cut-off level but were significantly different from those of the nontuberculous group, the use of PCT should be further investigated.  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