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   177篇
  免费   9篇
儿科学   4篇
妇产科学   1篇
基础医学   24篇
临床医学   14篇
内科学   44篇
神经病学   9篇
特种医学   3篇
外科学   18篇
综合类   10篇
预防医学   33篇
眼科学   19篇
药学   5篇
肿瘤学   2篇
  2024年   1篇
  2023年   2篇
  2022年   4篇
  2021年   10篇
  2020年   5篇
  2019年   8篇
  2018年   10篇
  2017年   6篇
  2016年   5篇
  2015年   2篇
  2014年   6篇
  2013年   9篇
  2012年   11篇
  2011年   17篇
  2010年   8篇
  2009年   2篇
  2008年   9篇
  2007年   6篇
  2006年   10篇
  2005年   6篇
  2004年   7篇
  2003年   8篇
  2002年   7篇
  2001年   3篇
  2000年   2篇
  1998年   1篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1992年   5篇
  1991年   2篇
  1990年   1篇
  1989年   2篇
  1988年   1篇
  1987年   1篇
  1985年   2篇
  1984年   1篇
  1970年   1篇
排序方式: 共有186条查询结果,搜索用时 15 毫秒
11.
Magnetic resonance spectroscopy, a noninvasive neuroimaging method, is a technique with the potential to measure in vivo neurochemical changes to different medication treatments. Symptoms of attention deficit hyperactivity disorder (ADHD) improved in two children treated with methylphenidate and two children treated with atomoxetine, for whom pre- and posttreatment proton magnetic resonance spectroscopy examinations were obtained to assess the relation between the neurochemical profiles in the striatum and prefrontal cortex among symptom severity and response to treatment. In the striatum, a striking decrease in the glutamate/creatine ratio (mean change 56.1%) was observed between 14 and 18 weeks of therapy in all four children with ADHD. In the prefrontal cortex, however, changes in the glutamate/creatine ratio were noted only in subjects receiving atomoxetine, not in those receiving methylphenidate. These data suggest that in vivo magnetic resonance spectroscopy measurement has the potential to assess response to psychopharmacological treatment in children with ADHD.  相似文献   
12.
Lobar torsion is a rare complication following lung transplantation. Early detection and immediate therapeutic intervention can lead to a favorable outcome. We report an unusual case of left lingular torsion following single lung transplantation performed for idiopathic pulmonary fibrosis. The patient experienced severe ventilatory compromise immediately after leaving the operating room, and a chest X-ray revealed a well-demarcated area of consolidation involving the left mid- and lower lung zones. Lingular torsion was promptly diagnosed and corrected surgically. The possibility of acute lobar torsion should be considered in lung transplant recipients who experience acute respiratory compromise in the early postoperative period. Early diagnosis and correction can avoid pulmonary infarction and the need for lobar resection.  相似文献   
13.
Pre-cut papillotomy.   总被引:4,自引:0,他引:4  
  相似文献   
14.
The capacity of peripheral blood monocytes and alveolar macrophages (AM) obtained by bronchoalveolar lavage (BAL) to present recall antigens, namely, tuberculin purified protein derivative (PPD) or streptokinase-streptodornase (SKSD), to highly purified autologous T-cells has been studied in 11 asthmatic and 11 healthy, nonatopic normal subjects. In the asthmatic group, AM accessory cell function was variable, and most subjects were unable to present either recall antigen as effectively as blood monocytes, although one asthmatic subject demonstrated larger proliferative responses than blood monocytes for both antigens. AM accessory cell activity was not antigen-specific, and there was a correlation between accessory cell efficacy for the two antigens (r = 0.92; confidence interval, 0.53 to 0.98). Furthermore, a correlation existed between the percentage lymphocyte count in the BAL fluid and the ratio of macrophage to monocyte antigen-presenting capability for both PPD (r = 0.92; 95% confidence interval, 0.83 to 0.99) and SKSD (r = 0.90; 95% confidence interval, 0.45 to 0.98). In the normal subjects, AM were also unable to act effectively as accessory cells for the presentation of PPD and SKSD in the majority of subjects. No correlation existed between the percentage lymphocytes in BAL fluid and the ratio of AM to monocyte accessory cell function. These results suggest an association between AM accessory function and the presence of BAL lymphocytes in bronchial asthma.  相似文献   
15.
This is the first report of the largest epidemic of dengue hemorrhagic fever (DHF) virus infection (2006) with IgM-confirmed cases from Karachi, Pakistan. Medical records of 172 IgM-positive patients were reviewed retrospectively for demographic, clinical and laboratory data. Patients were categorized into dengue fever (DF) and DHF according to the WHO severity grading scale. The mean+/-SD age of the patients was 25.9+/-12.8 years, 55.8% were males and the hemoconcentration was recorded in a small number of patients [10 (7.0%)]. Male gender [odds ratio (OR)=14.7, P=0.003), positive history of vomiting (OR=4.3, P=0.047), thrombocytopenia at presentation (OR=225.2, P<0.001) and monocytosis (OR=5.8, P=0.030) were independently associated with DHF, but not with DF. Five cases (2.9%) had a fatal outcome, with a male-to-female ratio of 1:4. Three were from a pediatric group (<15 years). Pulmonary hemorrhages, disseminated intravascular coagulation and cerebral edema preceded death in these patients. The results have highlighted significant findings, such as adult susceptibility to DHF, pronounced abdominal symptoms and lack of hemoconcentration at time of presentation in the study population. These findings may play an important role in the case definitions of future studies from this part of the world.  相似文献   
16.
In recent years, there has been a resurgence of interest in developing green and renewable alternate energy sources as a solution to the energy and environmental problems produced by conventional fossil fuel use. As a very effective energy transporter, hydrogen (H2) is a possible candidate for the future energy supply. Hydrogen production by water splitting is a promising new energy option. Strong, efficient, and abundant catalysts are required for increasing the efficiency of the water splitting process. Cu-based materials as an electrocatalyst have shown promising results for application in the Hydrogen Evolution Reaction (HER) and Oxygen Evolution Reaction (OER) in water splitting. In this review, our aim is to cover the latest developments in the synthesis, characterisation, and electrochemical behaviour of Cu-based materials as a HER, and OER electrocatalyst, highlighting the impact that these advances have had on the field. It is intended that this review article will serve as a roadmap for developing novel, cost-effective electrocatalysts for electrochemical water splitting based on nanostructured materials with particular emphasis on Cu-based materials for electrocatalytic water splitting.

In recent years, there has been a resurgence of interest in developing green and renewable alternate energy sources as a solution to the energy and environmental problems produced by conventional fossil fuel use.  相似文献   
17.
PURPOSE: To investigate the presence of retinal nerve fiber layer (RNFL) thinning and determine the relationship between RNFL thickness and visual field sensitivity loss in glaucoma patients with asymmetric hemifield visual field loss. PATIENTS AND METHODS: Thirty glaucoma patients with asymmetric hemifield visual field loss and 30 normal control subjects were included in the study. RNFL thickness was measured by optical coherence tomography and visual field sensitivity was measured by automated perimetry. Glaucoma patients with advanced visual field loss restricted to 1 hemifield and early or absent glaucomatous field loss in the other hemifield on the basis of the visual field data were included. Visual field sensitivity and mean deviation (MD) were averaged separately in each of the 2 hemifields. The hemifields in each eye were categorized as early (MD>or=-6 dB) and advanced (MD<-6 dB) glaucomatous hemifields. RESULTS: RNFL thickness measurements in corresponding (eg, superior peripapillary quadrant with inferior hemifield) advanced glaucomatous hemifields (59+/-16 microm) were significantly (P<0.001) lower than in corresponding early glaucomatous hemifields (90+/-25 microm). The mean RNFL thickness in corresponding advanced and early glaucomatous hemifields were significantly lower than in normal control subjects (P<0.0001). On the basis of the normative database supplied by optical coherence tomography software, 100% and 43% of eyes had abnormal RNFL thickness in corresponding advanced and early glaucomatous hemifields, respectively. A linear correlation was found between RNFL thickness and MD in the early (r=0.6; P<0.001) and advanced (r=0.5; P=0.007) glaucomatous hemifields. CONCLUSIONS: RNFL thinning was present in corresponding hemifields of glaucomatous eyes with minimal visual field defect and correlated with visual field sensitivity loss. Measurement of RNFL thickness has potential for detection of early nerve fiber loss owing to glaucoma.  相似文献   
18.
PURPOSE: To investigate oxygen tension (P(O2)) changes in the retinal and choroidal vasculatures in response to visual stimulation by light flicker. METHODS: A previously developed optical section phosphorescence imaging system was used to measure P(O2) separately in the retinal veins, arteries, and capillaries and in the choroid before and during light flicker. Imaging was performed in rats during light flicker at frequencies between 0 and 14 Hz. Light flicker-induced changes in the chorioretinal vasculature P(O2) and arteriovenous P(O2) differences were determined. Retinal arterial and venous P(O2) were measured along blood vessels as a function of the distance from the optic nerve head. RESULTS: Retinal arterial P(O2) and arteriovenous P(O2) differences increased with increasing light flicker at frequencies up to 10 Hz, after which no further increase was observed. Significant increases in retinal arterial P(O2) (P = 0.009; n =10) and in retinal capillary P(O2) (P = 0.04, n = 10) were measured in response to light flicker at 10 Hz. Retinal arteriovenous P(O2) differences during light flicker were significantly greater than differences before light flicker (P = 0.01; n = 10). Retinal arterial P(O2) decreased significantly with increased distance from the optic nerve head (P < or = 0.004), whereas retinal venous P(O2) remained relatively unchanged (P > or= 0.4). CONCLUSIONS: Measurement of changes in the chorioretinal vasculature P(O2) can potentially advance the understanding of oxygen dynamics in challenged physiological states and in animal models of human retinal diseases.  相似文献   
19.
20.
Sleep and Breathing - Narcolepsy is an uncommon neurological disorder characterised by irresistible spells of sleep associated with abnormal rapid eye movement (REM) sleep. The association between...  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