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   1441篇
  免费   79篇
  国内免费   34篇
耳鼻咽喉   143篇
儿科学   20篇
妇产科学   36篇
基础医学   141篇
口腔科学   26篇
临床医学   137篇
内科学   132篇
皮肤病学   2篇
神经病学   169篇
特种医学   68篇
外科学   110篇
综合类   232篇
预防医学   69篇
眼科学   10篇
药学   190篇
  1篇
中国医学   42篇
肿瘤学   26篇
  2023年   11篇
  2022年   31篇
  2021年   65篇
  2020年   51篇
  2019年   45篇
  2018年   47篇
  2017年   44篇
  2016年   64篇
  2015年   55篇
  2014年   110篇
  2013年   115篇
  2012年   113篇
  2011年   95篇
  2010年   76篇
  2009年   66篇
  2008年   72篇
  2007年   84篇
  2006年   68篇
  2005年   46篇
  2004年   44篇
  2003年   32篇
  2002年   24篇
  2001年   18篇
  2000年   17篇
  1999年   23篇
  1998年   10篇
  1997年   11篇
  1996年   10篇
  1995年   10篇
  1994年   19篇
  1993年   4篇
  1992年   5篇
  1991年   10篇
  1990年   5篇
  1989年   5篇
  1988年   7篇
  1987年   5篇
  1986年   3篇
  1985年   4篇
  1984年   6篇
  1983年   4篇
  1982年   5篇
  1981年   5篇
  1980年   3篇
  1979年   5篇
  1977年   1篇
  1976年   1篇
排序方式: 共有1554条查询结果,搜索用时 125 毫秒
41.
The use of Amplatzer septal occluder for closing a residual aortopulmonary defect has been described. This is usually performed by femoral access. We report closure of a residual aortopulmonary defect using right internal jugular vein access in a patient who had no femoral access as a result of previous cannulation for surgical repair. The 1 cm defect was closed successfully using a 10 mm Amplatzer septal occluder.Technical difficulty anticipated was unfounded although it was more cumbersome than femoral access. Left to right cardiac defects including PDA and AP window are amenable to transcatheter closure through internal jugular vein access.  相似文献   
42.

Background

Principles and accuracy of image-guided transcranial Doppler (IG TCD) sonography have been published recently. However, it remains open whether combination of image guidance and TCD offers an additional clinical advantage. This study scores the accuracy of conventional TCD examinations and investigates the potential improvement of TCD data integrity and reliability regarding the additional use of IG.

Methods

Conventional TCD was performed by a group of experienced investigators, who were blinded to images of a navigation system tracking the Doppler probe, whereas an independent observer documented the TCD findings, acquired by the investigators, due to saving spatial data of the TCD sample volume using IG for subsequent analysis. In a second set of experiments, image guidance was available to investigators without any previous TCD experience.

Results

The analysis of 3D data of vessels (n = 173) labeled by experienced investigators in conventional TCD, revealed a rate of 37% misinterpreted Doppler signals regarding the target vessel. Correctness of labeling was comparable between the different vascular segments. The rate of correct labeling was higher for right- (69%) than for left-sided vessels (57%). In comparison, by using IG, TCD investigators without any previous TCD experience achieved a significantly lower rate of 10% (n = 39) mislabeled vessels.

Conclusions

Our data suggest, that misinterpretation of the vascular source of the Doppler signal is a common source of errors in conventional TCD. Visualization of the vascular anatomy by image guidance offers improved accuracy and reliability of TCD results and may positively influence the learning curve for inexperienced investigators.  相似文献   
43.
目的探讨应用小骨窗开颅血肿清除术加早期肢体康复治疗高血压脑出血的临床疗效。方法对38例高血压脑出血患者行小骨窗开颅血肿清除术加早期肢体康复治疗。分析手术时机及早期康复训练治疗特点,以术后6个月日常生活能力(ADL)评价康复后效果。结果术后六个月以改良ADL分级法评价患者预后,I级14例,II级18例,III级2例,IV级3例,V级1例。其中良好生存32例,占84.2%;重残或植物状态生存6例,占15.8%。疗效良好。结论小骨窗开颅血肿清除术加早期肢体康复治疗高血压脑出血能明显提高临床疗效,降低病残率。  相似文献   
44.
目的采用在线近红外光谱(NIRS)技术,建立桂枝茯苓胶囊流化床干燥过程水分实时监测模型。方法通过NIRS漫反射探头采集16个生产批次共176个样本进行建模,优选移动窗口平滑法进行光谱预处理,采用间隔偏最小二乘法(si PLS)结合移动窗口偏最小二乘法(mw PLS)筛选特征变量为4 759.45~5 338.00 cm-1、5 503.84~6 101.67 cm-1、8 512.25~8 809.24cm-1,采用偏最小二乘(PLS)法建立水分含量多变量校正模型。结果水分预测的交叉验证均方根误差(RMSECV)为0.243%,性能偏差比(RPD)值为13.384,预测相对偏差(RSEP)为0.270%。以8个生产批次对在线监控方法的可靠性进行持续验证,结果 40个样本的相对预测误差均小于4.7%。干燥过程水分实时监测趋势图显示可准确判断干燥终点,终点样本水分含量位于控制限内。结论在线NIRS结合PLS建立的定量模型,可应用于生产规模桂枝茯苓胶囊流化床干燥过程水分含量在线监控且预测性能稳健、准确。  相似文献   
45.
ObjectivePublished reports on directional deep brain stimulation (DBS) have been limited to small, single-center investigations. Therapeutic window (TW) is used to describe the range of stimulation amplitudes achieving symptom relief without side effects. This crossover study performed a randomized double-blind assessment of TW for directional and omnidirectional DBS in a large cohort of patients implanted with a DBS system in the subthalamic nucleus for Parkinson's disease.Materials and MethodsParticipants received omnidirectional stimulation for the first three months after initial study programming, followed by directional DBS for the following three months. The primary endpoint was a double-blind, randomized evaluation of TW for directional vs omnidirectional stimulation at three months after initial study programming. Additional data recorded at three- and six-month follow-ups included stimulation preference, therapeutic current strength, Unified Parkinson's Disease Rating Scale (UPDRS) part III motor score, and quality of life.ResultsThe study enrolled 234 subjects (62 ± 8 years, 33% female). TW was wider using directional stimulation in 183 of 202 subjects (90.6%). The mean increase in TW with directional stimulation was 41% (2.98 ± 1.38 mA, compared to 2.11 ± 1.33 mA for omnidirectional). UPDRS part III motor score on medication improved 42.4% at three months (after three months of omnidirectional stimulation) and 43.3% at six months (after three months of directional stimulation) with stimulation on, compared to stimulation off. After six months, 52.8% of subjects blinded to stimulation type (102/193) preferred the period with directional stimulation, and 25.9% (50/193) preferred the omnidirectional period. The directional period was preferred by 58.5% of clinicians (113/193) vs 21.2% (41/193) who preferred the omnidirectional period.ConclusionDirectional stimulation yielded a wider TW compared to omnidirectional stimulation and was preferred by blinded subjects and clinicians.  相似文献   
46.
机械取栓术治疗急性大血管闭塞性缺血性脑卒中(LVO-AIS )的主要方式,研究证实机械取栓的明确时间窗为发病内6h,然而对于发病6-24h或超过24h接受机械取栓的患者筛选仍存争议,本研究旨在探讨超时间窗机械取栓的安全性和有效性评估。  相似文献   
47.
Conclusions With the aggravation of the external auditory canal malformation, the size of extra-niche fossa became smaller, providing concrete data and valuable information for the better design, selecting and safer implantation of the transducer in the area of round window niche. Three-dimensional measurements and assessments before surgery might be helpful for a safer surgical approach and implantation of a vibrant soundbridge.

Objectives The aim of this study was to investigate whether differences exist in the morphology of the posterior tympanum related to the round window vibroplasty among congenital aural atresia (CAA), congenital aural stenosis (CAS), and a normal control group, and to analyze its effect on the round window implantation of vibrant soundbridge.

Methods CT images of 10 normal subjects (20 ears), 27 CAS patients (30 ears), and 25 CAA patients (30 ears) were analyzed. The depth and the size of outside fossa of round window niche related to the round window vibroplasty (extra-niche fossa)and the distances between the center of round window niche and extra-niche fossa were calculated based on three-dimensional reconstruction using mimics software. Finally, the data were analyzed statistically.

Results The size of extra-niche fossa in the atresia group was smaller than in the stenosis group (p?p?相似文献   
48.
孙政  卞上  王家文 《安徽医学》2016,37(8):957-961
目的 对比分析细孔钻颅术血肿抽吸术和小骨窗血肿清除术治疗老年高血压脑出血的疗效、安全性以及预后。方法 选择2014年1月至2015年1月亳州市人民医院收治的80例高血压脑出血患者,采用投掷硬币法将患者随机分为观察组40例及对照组40例,观察组行细孔钻颅血肿抽吸术,对照组行小骨窗血肿清除术,对比两组患者的手术效果、并发症、神经功能恢复情况及生存质量。结果 观察组手术时间、血肿吸收时间和住院时间均显著短于对照组(P<0.05),观察组血肿清除率、术后恢复率均高于对照组,差异有统计学意义(P<0.05),重残率、并发症均低于对照组(5.00% vs 45.00%,20.00% vs 27.50%),差异有统计学意义(P<0.05);出院时、术后随访期间美国国立卫生研究院卒中量表(NIHSS)评分均显著低于对照组(P<0.05),观察组患者随访6个月、1年生存质量评分均高于对照组(P<0.05)。结论 细孔钻颅术较小骨窗血肿清除术治疗老年高血压脑出血疗效更为显著,并发症发生率低,术后恢复率高,且可明显改善患者神经功能和生存质量。  相似文献   
49.
目的 探讨高血压性脑出血(hypertensive intracerebral hemorrhage,HICH)患者小骨窗手术术后再出血的影响因素。方法 选取2019年1月至2021年12月于台州市第一人民医院进行小骨窗手术的HICH患者150例为研究对象,通过自制调查问卷收集患者相关临床资料,统计HICH患者小骨窗手术术后再出血的发生率,采用多因素Logistic回归分析探究HICH患者小骨窗手术术后再出血的危险因素。结果 在收回问卷的145例HICH患者中,35例发生术后再出血,再出血率24.14%。单因素分析结果显示,发病至手术时间<6h、术前收缩压≥200mmHg(1mmHg=0.133kPa)、术前舒张压≥120mmHg、高血压病程≥10年、凝血功能异常、血肿形状不规则、合并糖尿病、出血破入脑室的HICH患者小骨窗手术术后再出血的发生率较高,差异均有统计学意义(P<0.05)。多因素Logistic回归分析结果显示,发病至手术时间<6h、术前收缩压≥200mmHg、术前舒张压≥120mmHg、高血压病程≥10年、凝血功能异常、血肿形状不规则、合并糖尿病、出血破入脑室均为影响HICH患者小骨窗手术术后发生再出血的主要危险因素(P<0.05)。结论 手术时机、术前血压、高血压病程、凝血功能、血肿形状、合并糖尿病、出血破入脑室均是HICH患者小骨窗手术术后再出血的危险因素,应把握手术时机,严密监测患者的血压、凝血功能等,对改善患者预后意义深远。  相似文献   
50.
Window of opportunity therapies, which involve short‐term administration of systemic therapy between cancer diagnosis and surgery, have raised significant interest in recent years as a mean of assessing the sensitivity of a patient's cancer to therapy prior to surgery. There is now compelling evidence that in patients with early stage hormone‐receptor positive breast cancer, a 2‐week preoperative treatment with standard hormone therapies in a preoperative window period provides important prognostic information, which in turn helps to aid decision‐making regarding treatment options. Changes in short‐term biomarker endpoints such as cell proliferation measured by Ki‐67 can act as surrogate markers of long‐term outcomes. Paired tissues obtained pre‐ and post‐investigational treatment, without having to subject the patient to additional biopsies, can then be used to conduct translational research to investigate predictive biomarkers and pharmacodynamics. In this review, we will examine the utility and challenges of window of opportunities therapies in breast cancer in the current literature, and the current Australian and international trial landscape in this clinical space.  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