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   1025篇
  免费   75篇
  国内免费   1篇
耳鼻咽喉   7篇
儿科学   18篇
妇产科学   57篇
基础医学   91篇
口腔科学   14篇
临床医学   185篇
内科学   219篇
皮肤病学   16篇
神经病学   55篇
特种医学   35篇
外科学   159篇
综合类   11篇
预防医学   81篇
眼科学   5篇
药学   102篇
中国医学   1篇
肿瘤学   45篇
  2023年   3篇
  2022年   6篇
  2021年   16篇
  2020年   13篇
  2019年   25篇
  2018年   18篇
  2017年   18篇
  2016年   19篇
  2015年   15篇
  2014年   22篇
  2013年   38篇
  2012年   45篇
  2011年   61篇
  2010年   40篇
  2009年   36篇
  2008年   62篇
  2007年   58篇
  2006年   56篇
  2005年   47篇
  2004年   45篇
  2003年   41篇
  2002年   45篇
  2001年   31篇
  2000年   35篇
  1999年   21篇
  1998年   18篇
  1997年   15篇
  1996年   5篇
  1995年   14篇
  1993年   4篇
  1992年   15篇
  1991年   18篇
  1990年   22篇
  1989年   21篇
  1988年   18篇
  1987年   13篇
  1986年   14篇
  1985年   15篇
  1984年   4篇
  1983年   12篇
  1982年   6篇
  1981年   5篇
  1980年   4篇
  1979年   3篇
  1978年   7篇
  1977年   4篇
  1976年   6篇
  1975年   3篇
  1973年   6篇
  1963年   4篇
排序方式: 共有1101条查询结果,搜索用时 15 毫秒
101.
BACKGROUND: Functional status has been quantified in the adult low back pain (LBP) population, but has not been characterized for older adults with spinal symptoms. OBJECTIVES: To compare pain severity and functional status of older adults with and without spinal symptoms, and to determine what factors are associated with quality of life in the spinal stenosis and axial LBP groups. METHODS: In 24 subjects greater than 55-years old with lumbar spinal stenosis, 12 with LBP, and 12 without spinal symptoms, obtain the following: pain severity with 10-cm visual analog scale (VAS), 15-minute walk test, 7-day walking distance, Quebec Back Pain Disability Scale (QBPDS), and Pain Disability Index (PDI). RESULTS: The mean scores were worst for the stenosis group, were intermediate for the LBP group, and were the best for the asymptomatic group. Analysis of variance showed that the pain VAS (p < 0.001), 15-minute walk test (p = 0.01), 7-day walk (p = 0.02), QBPDS (p < 0.001), and PDI (p < 0.001) were different between at least two groups. All the variables in the stenosis group were worse than in the asymptomatic group, but only the pain VAS, QBPDS, and PDI in the LBP group were worse than in the asymptomatic group. In both the stenosis and LBP group the QBPDS and PDI were only related to pain VAS. CONCLUSION: Seniors with spinal stenosis and LBP have more disability than asymptomatic seniors. The 15-minute walking test with the stenosis group was slower than with the asymptomatic seniors. However, they compensate so that their 7-day walking distance is not as significantly decreased.  相似文献   
102.
BACKGROUND: Minimally invasive surgery has been developed to reduce incision length, muscle damage, and rehabilitation time. However, reduced exposure of anatomical landmarks may result in technical errors and inferior implant survivorship. The objective of this study was to compare in vivo motions and hip joint contact forces during gait in total hip arthroplasty subjects, performed with either minimally invasive surgery or standard surgical approaches. METHODS: Fifteen subjects implanted using either minimally invasive surgery anterolateral, minimally invasive surgery posterolateral, or traditional posterolateral total hip arthroplasty were evaluated using fluoroscopy while performing gait on a treadmill. Kinematics, obtained using 3D-to-2D image registration technique, were input as temporal functions in a 3D inverse dynamic mathematical model that determines in vivo soft tissue and hip contact forces. FINDINGS: The subjects implanted with posterolateral and anterolateral minimally invasive surgery demonstrated significantly less separation than those implanted with the traditional approach (P<0.01). The minimally invasive surgery subjects also experienced lower average maximum peak forces, with 3.2 body weight for the anterolateral minimally invasive surgery and 2.9 body weight for the posterolateral minimally invasive surgery subjects, compared to 3.5 body weight for the traditional subjects (P=0.02 and P=0.03, respectively). INTERPRETATION: This is the first study to compare in vivo weight-bearing kinematics, separation and kinetics for traditional, anterolateral minimally invasive surgery and posterolateral minimally invasive surgery total hip arthroplasty subject groups. Our data indicated in all analyzed parameters differences between the minimally invasive surgery and the traditional groups, with favorable results for the minimally invasive surgery subjects. This may be related, to a reduction in stabilizing soft tissues after a minimally invasive surgery procedure, leading to lower bearing surface forces at the femoral head--acetabular cup interface.  相似文献   
103.
Myocardial performance index (MPI) is an echocardiographic Doppler-derived measure of ventricular function previously validated in patients with congenital heart disease. It may be preferred over conventional noninvasive measures of ventricular function in patients with complex anatomy because it is dependent on neither geometric shape nor heart rate. Brain natriuretic peptide (BNP) is a predictor of systolic and diastolic dysfunction in anatomically correct hearts. The correlation of BNP to MPI in patients with congenital heart disease was determined. Fifty-four adults with congenital heart disease were evaluated. BNP was measured using standardized assays. Doppler echocardiography was performed within 6 months of BNP assay. There were no changes in clinical status during this interval. An experienced observer was blinded and evaluated all echocardiographic images, and MPI and ejection fraction (EF) were determined. Left ventricular (LV) or univentricular MPI was calculated in 34 patients and right ventricular (RV) MPI was calculated in 23 patients. Pearson's correlation coefficient test showed that BNP significantly correlated with LV/univentricular MPI (r = 0.461, p = 0.006) and RV MPI (r = 0.748, p <0.0001), whereas LV/univentricular EF and RVEF had no significant correlation with BNP (r = -0.189, p = 0.172; r = 0.066, p = 0.729, respectively). In patients with congenital heart disease, BNP correlated significantly with MPI, but not with LV, RV, or univentricular EF. This is particularly true in patients with geometrically variable right ventricles in which EF may be more difficult to assess. In conclusion, these findings emphasize the unique ability of both BNP and MPI to assess global ventricular function in geometrically complex hearts.  相似文献   
104.
Centrally acting mechanisms for the treatment of male sexual dysfunction   总被引:1,自引:0,他引:1  
The development of pharmacologic therapy for erectile dysfunction (ED) has been possible because of incremental growth in our understanding of the physiology of normal erections and the complex pathophysiology of ED. Although the oral phosphodiesterase type 5 (PDE5) inhibitors have provided safe, effective treatment of ED for some men, a large proportion of men who have ED do not respond to PDE5 inhibitors or become less responsive or less satisfied as the duration of therapy increases. Also, men who are receiving organic nitrates and nitrates, such as amyl nitrate, cannot take PDE5 inhibitors because of nitrate interactions. The current options for treatment beyond PDE5 inhibitors are invasive, unappealing to some patients, and sometimes ineffective. The search for other options by which ED can be treated has branched out and now encompasses centrally acting mechanisms that control erectile function. Drugs available in Europe include apomorphine. This article focuses on the mechanism of centrally acting agents and reviews clinical data on potential new centrally acting drugs for men who have ED.  相似文献   
105.
106.
107.
The Currarino syndrome is a form of caudal regression syndrome characterized by the classic triad of presacral mass, sacral bone defect and anorectal malformation in which an autosomal dominant inheritance has been described. In case of clinical suspicion it is necessary to search for the classic alterations and to detect other possible associated malformations in order to avoid complications. The management is multidisciplinary and depends on the type of alterations that the patient has. We report a 17-month-old female baby that initially passed unnoticed and was detected during a rectoplasty for reconstruction of a rectal stenosis. The baby presented complications derived from ignorance of the existence of a presacral mass. Early diagnose and adequate treatment is very important.  相似文献   
108.
109.
110.
Parkinson's disease (PD) represents a common but challenging condition in which an increasing number of therapeutic options have evolved over the course of the last 50 years. The introduction of dopaminergic therapies has dramatically improved outcomes but life expectancies remain significantly curtailed. Currently, all available treatment options are directed towards the amelioration of symptoms. However, it is hoped that a greater understanding of the distinctive pathology underlying PD might offer some novel therapeutic approaches.The identification of degeneration within the nigrostriatal tract as the most prominent pathological process in PD has led to the development of a number of therapies. However, despite initially good symptomatic control it has become clear that the longer-term use of these medications is associated with a number of debilitating motor complications. The management of these drug-related issues has necessitated a further tier of therapeutic options based largely on a greater understanding of the basal ganglia circuitry involved. Indeed, surgical interventions targeting these neural circuits have provided increased control of motor symptoms in patients with advanced disease, however, such techniques still fail to slow or reverse the disease. To this end, a number of novel approaches focussed on restoration or repair of the diseased brain have received increasing attention. Nevertheless, there are multiple symptoms that are unresponsive to any of these therapies, highlighting the involvement of other neurotransmitter systems and the complexities of the disease beyond the basal ganglia circuitry. An appreciation of the ongoing neurodegenerative processes at the core of PD and the burden of disease associated with them, emphasises the need for increased research into more effective and comprehensive treatment methodologies.  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