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   2320篇
  免费   139篇
  国内免费   9篇
耳鼻咽喉   52篇
儿科学   142篇
妇产科学   16篇
基础医学   208篇
口腔科学   42篇
临床医学   124篇
内科学   566篇
皮肤病学   41篇
神经病学   92篇
特种医学   133篇
外科学   432篇
综合类   41篇
一般理论   1篇
预防医学   61篇
眼科学   124篇
药学   210篇
中国医学   10篇
肿瘤学   173篇
  2023年   27篇
  2022年   43篇
  2021年   103篇
  2020年   84篇
  2019年   87篇
  2018年   106篇
  2017年   75篇
  2016年   108篇
  2015年   95篇
  2014年   142篇
  2013年   155篇
  2012年   237篇
  2011年   225篇
  2010年   117篇
  2009年   88篇
  2008年   138篇
  2007年   141篇
  2006年   105篇
  2005年   109篇
  2004年   88篇
  2003年   80篇
  2002年   54篇
  2001年   9篇
  2000年   6篇
  1999年   11篇
  1998年   8篇
  1997年   5篇
  1996年   3篇
  1995年   3篇
  1994年   2篇
  1993年   6篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1988年   4篇
  1975年   1篇
排序方式: 共有2468条查询结果,搜索用时 15 毫秒
91.
Parathyroid hormone (PTH) has been a major contributor to the anabolic therapy for osteoporosis, but its delivery to bone without losing activity and avoiding adverse local effects remain a challenge. Being the natural component of bone, use of hydroxyapatite for this purpose brings a major breakthrough in synergistic anabolism. This study focuses on synthesis, characterization and evaluation of in vitro and in vivo efficacy of PTH (1-34) adsorbed hydroxyapatite nanocarrier for synergistic enhancement in the anabolic activity of PTH for bone regeneration. The negative zeta potential of this nanocarrier facilitated its affinity to the Ca2+ rich bone tissue and solubilization at low pH enhanced specific delivery of PTH to the resorption pits in osteoporotic bone. In this process, PTH retained its anabolic effect and at the same time an increase in bone mineral content indicated enhancement of the net formative effect of the PTH anabolic therapy.  相似文献   
92.

Background

Stenosis of saphenous vein grafts (SVGs) after coronary artery bypass grafting (CABG) is common and often requires percutaneous coronary interventions (PCI) for treatment. However, data for the effectiveness of drug-eluting stents (DES) versus bare-metal stents (BMS) in SVG-PCI are unclear.

Objectives

This study sought to examine the association between DES versus BMS used during SVG PCI and clinical outcomes in the national Veterans Affairs integrated healthcare system.

Methods

We studied a national cohort of 2,471 post-CABG veterans undergoing SVG-PCI between 2008 and 2011 at all Veterans Affairs hospitals and compared clinical outcomes of between those receiving DES and BMS. Clinical outcomes included procedural complications, myocardial infarction (MI), and all-cause mortality. Comparisons were made in a propensity-matched cohort using Cox proportional hazards regression models.

Results

DES were used in 1,549 SVG-PCI patients (63%) and the use of DES increased progressively with each calendar year (50% in 2008 to 69% in 2011). Incidence of procedural complications was low and comparable in both groups (2.8% among BMS vs. 2.3% among DES patients; p = 0.54). During long-term (>2 years) follow-up, use of DES was associated with lower mortality than BMS (hazard ratio [HR]: 0.72; 95% confidence interval [CI]: 0.57 to 0.89) and similar rates of MI (HR: 0.94; 95% CI: 0.71 to 1.24) in the propensity-matched cohort.

Conclusions

In a national cohort of veterans, we observed widespread and increasing use of DES during SVG-PCI. In long-term follow-up, compared with BMS, DES use was safe and effective in SVG-PCI patients.  相似文献   
93.
94.
95.
European Journal of Nuclear Medicine and Molecular Imaging - One of the primary prerequisites for peptide receptor radionuclide therapy (PRRT) in patients with neuroendocrine tumors (NET) is the...  相似文献   
96.
European Journal of Nuclear Medicine and Molecular Imaging - 68Ga-PSMA-11-PET/CT is increasingly used in early-stage biochemical recurrence of prostate cancer to detect potential lesions for an...  相似文献   
97.

Postmortem studies reported plaque erosion is frequent in young women. Recent in vivo studies failed to show age and sex differences in the plaque erosion prevalence. The aim of this study was to investigate the prevalence of plaque erosion by age and sex among acute coronary syndromes (ACS) patients. From 1699 ACS patients, 1083 with plaque erosion or rupture were analyzed. Patients were categorized as 5 age groups (≤?50, 51–60, 61–70, 71–80,?≥?81 years). Overall prevalence of plaque erosion was similar between males and females (p?=?0.831). Males age?≤?50 had higher (p?=?0.018) and age 71–80 had lower (p?=?0.006) prevalence of plaque erosion. Females age 61–70 had higher (p?=?0.021) and age 71–80 had lower (p?=?0.045) prevalence of plaque erosion. In advanced age groups (≥?71 years), rupture was the dominant etiology in both sexes. In multivariate analysis of males, age?≤?50 demonstrated a trend to increase (OR 1.418, 95% CI 0.961–2.093, p?=?0.078) the erosion risk. Females age?≤?70 independently increased (OR 2.138, 95% CI 1.249–3.661, p?=?0.006) the risk for erosion. The prevalence of plaque erosion was similar between males and females. Plaque erosion risk was increased in the males age?≤?50 and in the females age?≤?70 among ACS patients.

  相似文献   
98.
International Journal of Diabetes in Developing Countries - Resistin (RETN) protein plays an important role in the regulation of energy, glucose, and lipid homeostasis and maintenance of fasting...  相似文献   
99.
Precise detection and quantification of white matter hyperintensities (WMH) observed in T2‐weighted Fluid Attenuated Inversion Recovery (FLAIR) Magnetic Resonance Images (MRI) is of substantial interest in aging, and age‐related neurological disorders such as Alzheimer's disease (AD). This is mainly because WMH may reflect co‐morbid neural injury or cerebral vascular disease burden. WMH in the older population may be small, diffuse, and irregular in shape, and sufficiently heterogeneous within and across subjects. Here, we pose hyperintensity detection as a supervised inference problem and adapt two learning models, specifically, Support Vector Machines and Random Forests, for this task. Using texture features engineered by texton filter banks, we provide a suite of effective segmentation methods for this problem. Through extensive evaluations on healthy middle‐aged and older adults who vary in AD risk, we show that our methods are reliable and robust in segmenting hyperintense regions. A measure of hyperintensity accumulation, referred to as normalized effective WMH volume, is shown to be associated with dementia in older adults and parental family history in cognitively normal subjects. We provide an open source library for hyperintensity detection and accumulation (interfaced with existing neuroimaging tools), that can be adapted for segmentation problems in other neuroimaging studies. Hum Brain Mapp 35:4219–4235, 2014. © 2014 Wiley Periodicals, Inc .  相似文献   
100.
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