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   50篇
  免费   4篇
妇产科学   2篇
基础医学   1篇
临床医学   7篇
内科学   4篇
神经病学   12篇
特种医学   1篇
外科学   1篇
预防医学   3篇
眼科学   17篇
药学   1篇
肿瘤学   5篇
  2022年   2篇
  2021年   3篇
  2020年   3篇
  2019年   2篇
  2018年   4篇
  2016年   2篇
  2015年   5篇
  2013年   5篇
  2010年   1篇
  2008年   5篇
  2007年   4篇
  2006年   3篇
  2005年   1篇
  2004年   1篇
  2003年   4篇
  2002年   2篇
  1998年   1篇
  1990年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1974年   2篇
排序方式: 共有54条查询结果,搜索用时 62 毫秒
1.
2.

Background

One strategy to address health problems related to insufficient physical activity is to examine modifiable neighborhood characteristics associated with active transportation.

Purpose

The aim of this study is to evaluate whether neighborhoods with more aesthetic amenities (sidewalk cafés, street trees, and clean sidewalks) and fewer safety hazards (pedestrian-auto fatalities and homicides) are associated with active transportation.

Methods

The 2003 Community Health Survey in New York City, which asked about active transportation (walking or bicycling >10 blocks) in the past 30 days, was linked to ZIP-code population census and built environment characteristics. Adjusted associations were estimated for dichotomous (any active transportation versus none) and continuous (trip frequency) active transportation outcomes.

Results

Among 8,034 adults, those living near sidewalk cafés were 10 % more likely to report active transportation (p?=?0.01). Homicide rate was associated with less frequent active transportation among those reporting any active transportation (p?=?0.002).

Conclusions

Investments in aesthetic amenities or homicide prevention may help to promote active transportation.
  相似文献   
3.
Neural stem cell (NSC) transplantation has been shown to attenuate the severity of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS). Central to the future success of NSC transplantation in MS is the ability of transplanted cells to migrate from the site of transplantation to relevant foci of disease. Using magnetically labeled mouse neurospheres and human embryonic stem cell (hESC)-derived neurospheres, we applied serial magnetic resonance imaging (MRI) to assess the biodynamics of transplanted cell migration in a chronic mouse EAE model. Magnetic labeling did not affect the in vitro and in vivo characteristics of cells as multipotential precursors. Cell migration occurred along white matter (WM) tracts (especially the corpus callosum (CC), fimbria, and internal capsule), predominantly early in the acute phase of disease, and in an asymmetric manner. The distance of cell migration correlated well with clinical severity of disease and the number of microglia in the WM tracts, supporting the notion that inflammatory signals promote transplanted cell migration. This study shows for the first time that hESC-derived neural precursors also respond to tissue signals in an MS model, similarly to rodent cells. The results are directly relevant for designing and optimizing cell therapies for MS, and achieving a better understanding of in vivo cell dynamics and cell-tissue interactions.  相似文献   
4.
Coarctation of the aorta. Longitudinal assessment of operated patients   总被引:4,自引:0,他引:4  
A B Simon  A E Zloto 《Circulation》1974,50(3):456-464
  相似文献   
5.
Atrioventricular block: natural history after permanent ventricular pacing   总被引:4,自引:0,他引:4  
The preimplantation status, postimplantation morbidity and causes of late mortality were summarized for 246 patients who underwent pacing for atrioventricular (A-V) block at the University of Michigan for the 14 years from 1961 to 1974. The survival rate at 1, 5 and 10 years was 88, 61 and 49 percent, respectively. Risk of death was greatest among patients with antecedent ischemic or hypertensive heart disease or congestive heart failure in the period before pacemaker implantation, patients older than 74 years at initial implantation and those receiving a pacemaker before 1965. Forty-two percent of the 109 deaths were related to apparent progression of underlying cardiac disease. Pacing system malfunction was a contributing documented cause of only 3 deaths. Even with permanent pacemaker implantation, patients with A-V block have a higher age-specific mortality rate than the general U.S. population. Survival improved steadily over the period of study. This change is attributed to apparent improvements in treatment of cardiovascular disease including more effective treatment of congestive heart failure and valve replacement for selected patients as well as elimination of immediate postoperative mortality.  相似文献   
6.
7.
Fifty-nine patients between the ages of 13 and 88 with sinus node disease, who received a permanent ventricular pacemaker between 1965 and 1976 at one institution, were followed to determine the natural history of the disorder after permanent pacing. Nineteen had ischemic heart disease, six had primary myocardial disease, and eight valvular heart disease. In 26, no etiology for the arrhythmia was apparent. The one- and five-year survival was 85.5% and 73.1%, respectively. Patients with underlying heart disease had a significantly poorer survival when compared to those without (58% versus 94% at 36 months) and all but 3 of 13 deaths in the first 36 months were in those with ischemic heart disease. There was a distinct trend toward poor survival in those with heart failure prior to pacemaker implant and those over age 65. Patients with sinus bradycardia alone did best (91% survival three years after implant), while those with bradycardia-tachycardia syndrome and those with sinoatrial arrest alone did distinctly worse (76% and 65% survival at three years, respectively). Twelve of 18 deaths were due to progression of underlying heart disease. The long-term prognosis with symptomatic sinus node disease can be predicted in part by (1) etiology of the underlying heart disease, (2) pre-implant arrhythmia, and (3) ventricular function prior to implant.  相似文献   
8.
Transplanted neural precursor cells remyelinate efficiently acutely demyelinated focal lesions. However, the clinical value of cell transplantation in a chronic, multifocal disease like multiple sclerosis will depend on the ability of transplanted cells to migrate to the multiple disease foci in the brain. Here, we expanded newborn rat neural precursor cells in spheres and transplanted them intracerebroventricularly or intrathecally in rats. The cells were labeled by the nuclear fluorescent dye Hoechst or by incubation with BrdU to enable their identification at 2 days and 2 weeks after transplantation, respectively. Spheres consisted of PSA-NCAM(+), nestin(+), NG2(-) undifferentiated precursor cells that differentiated in vitro into astrocytes, oligodendrocytes, and neurons. Spheres that were transplanted into intact rats remained mostly in the ventricles or in the spinal subarachnoid space. Following transplantation at peak of experimental autoimmune encephalomyelitis, cells migrated into the brain or spinal cord parenchyma, exclusively into inflamed white matter but not into adjacent gray matter regions. After 2 weeks, many transplanted cells had migrated into distant white matter tracts and acquired specific markers of the astroglial and oligodendroglial lineages. Thus, the inflammatory process may attract targeted migration of transplanted precursor cells into the brain parenchyma.  相似文献   
9.
10.
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