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   2471篇
  免费   196篇
  国内免费   6篇
耳鼻咽喉   15篇
儿科学   163篇
妇产科学   37篇
基础医学   498篇
口腔科学   56篇
临床医学   263篇
内科学   515篇
皮肤病学   16篇
神经病学   234篇
特种医学   71篇
外科学   262篇
综合类   22篇
预防医学   258篇
眼科学   22篇
药学   135篇
肿瘤学   106篇
  2024年   8篇
  2023年   11篇
  2022年   47篇
  2021年   51篇
  2020年   40篇
  2019年   39篇
  2018年   35篇
  2017年   55篇
  2016年   48篇
  2015年   62篇
  2014年   78篇
  2013年   118篇
  2012年   161篇
  2011年   161篇
  2010年   82篇
  2009年   88篇
  2008年   160篇
  2007年   132篇
  2006年   167篇
  2005年   127篇
  2004年   135篇
  2003年   155篇
  2002年   140篇
  2001年   51篇
  2000年   42篇
  1999年   43篇
  1998年   35篇
  1997年   21篇
  1996年   14篇
  1995年   26篇
  1994年   13篇
  1993年   9篇
  1992年   18篇
  1991年   23篇
  1990年   17篇
  1989年   20篇
  1988年   16篇
  1987年   22篇
  1986年   24篇
  1985年   18篇
  1984年   27篇
  1983年   28篇
  1982年   13篇
  1981年   15篇
  1980年   8篇
  1979年   16篇
  1977年   8篇
  1972年   6篇
  1969年   5篇
  1967年   5篇
排序方式: 共有2673条查询结果,搜索用时 15 毫秒
71.
72.
The aim of this study was to determine whether the administration of a lipid emulsion containing less polyunsaturated fatty acids but rich in monounsaturated fatty acids causes less in vivo lipid peroxidation in preterm infants. The prospective intervention study included 13 infants with birth weights and gestational ages ranging between 1,100 and 2,660 g and from 28.4 to 32.9 weeks. All were in a stable condition and randomly allocated for a 3-hour infusion (0.16 g/kg/h) of an olive oil-based and a soybean oil + medium chain fatty acid (MCT) emulsion on 2 consecutive days. Expired pentane and plasma triglycerides (TGs) were measured before, during, and after the 3-hour infusion. Basal exhaled pentane averaged 9.4 +/- 7.0 pmol/kg/min (mean +/- SD). During the olive oil-based emulsion, exhaled pentane increased to 95.2 +/- 56.7, and during soybean oil + MCT it increased to 110 +/- 93.9 pmol/kg/min (p < 0.05 both from basal, n.s. between preparations). One hour after discontinuation of the infusion, exhaled pentane returned to 21.1 +/- 12.6 pmol/kg/min (p < 0.05 vs. basal). Combined data on expired pentane measurements demonstrated that on day 1 pentane peaked at 124 +/- 87.0 pmol/kg/min which was significantly attenuated to 57.5 +/- 24.4 pmol/kg/min after an identical dose of lipid on day 2 (p < 0.05). No difference in peak TGs was detected between the two preparations or the study days. Infusion of a constant dose of intravenous lipids on 2 subsequent days to the newborn infants is associated with a reduction in lipid peroxidation. This finding may be dependent on normal postnatal maturation or may represent an appropriate adaptive response aiming at a reduction in oxidative stress. Peroxidation of soybean oil + MCT and olive oil-based lipid emulsions was similar in the newborn infants.  相似文献   
73.
In adults, HLA haplotype B8-DRB1*03 is clearly associated with a severe clinical course of nephropathia epidemica caused by Puumala hantavirus. We investigated whether the same applies in pediatric patients. This HLA haplotype was found in 20 of 39 (51%) of the patients, a significantly higher figure than in the Finnish population (19%). There were, however, no significant differences in the clinical picture between patients with and without HLA B8-DRB1*03.  相似文献   
74.
75.
76.
77.
78.
79.
PURPOSE: This study examined the hypothesis that neurodegeneration continues after status epilepticus (SE) ends and that the severity of damage at the early phase of the epileptogenic process predicts the outcome of epilepsy in a long-term follow-up. METHODS: SE was induced in rats by electrical stimulation of the amygdala, and the progression of structural alterations was monitored with multiparametric magnetic resonance imaging (MRI). Absolute T2, T1rho, and diffusion (Dav) images were acquired from amygdala, piriform cortex, thalamus, and hippocampus for < or = 4.5 months after SE. Frequency and type of spontaneous seizures were monitored with video-electroencephalography recordings. Histologic damage was assessed from Nissl, Timm, and Fluoro-Jade B preparations at 8 months. RESULTS: At the acute phase (2 days after SE induction), quantitative MRI revealed increased T2, T1rho, and Dav values in the primary focal area (amygdala), reflecting disturbed water homeostasis and possible early structural damage. Pathologic T2 and T1rho were observed in mono- or polysynaptically connected regions, including the piriform cortex, midline thalamus, and hippocampus. The majority of acute MRI abnormalities were reversed by 9 days after SE. In later time points (> 20 days after induction), both the T1rho and diffusion MRI revealed secondarily affected areas, most predominantly in the amygdala and hippocampus. At this time, animals began to have spontaneous seizures. The initial pathology revealed by MRI had a low predictive value for the subsequent severity of epilepsy and tissue damage. CONCLUSIONS: The results demonstrate progressive neurodegeneration after SE in the amygdala and the hippocampus and stress the need for continued administration of neuroprotectants in the treatment of SE even after electrographic seizure activity has ceased.  相似文献   
80.
Long-term outcome after intravenous thrombolysis of basilar artery occlusion   总被引:13,自引:0,他引:13  
Context  Basilar artery occlusion (BAO) is an infrequent disease with high morbidity and mortality. Intra-arterial thrombolysis is advocated for treatment but is limited to use at specialized centers. Objective  To evaluate outcomes for patients with BAO treated with intravenous thrombolytic therapy. Design, Setting, and Participants  During 1995 to 2003, 50 consecutive patients with angiographically proven BAO were treated according to an institutional therapy protocol based on intravenous thrombolysis with recombinant tissue plasminogen activator (alteplase). Patients were treated at an urban university teaching hospital receiving all patients with ischemic stroke who were considered for thrombolysis in a catchment area of 1.5 million inhabitants in Helsinki, Finland. Intervention  Intravenous administration of alteplase (0.9 mg/kg) during a 1-hour infusion. Main Outcome Measures  Basilar artery recanalization determined by magnetic resonance angiography and clinical outcomes at 3 months and at 1 year or longer determined by modified Rankin Scale and Barthel Index scores. Results  Recanalization was studied in 43 patients and verified in 26 (52%) of all patients. By 3 months, 20 patients (40%) had died while 11 had good outcomes (modified Rankin Scale score, 0-2); 12 (24%) reached independence in activities of daily living (Barthel Index score, 95-100), and 6 (16%) were severely disabled (Barthel Index score, 0-50). In the long term (median follow-up 2.8 years), 15 patients (30%) reached good outcomes (modified Rankin Scale score, 0-2) while 23 (46%) died. Conclusions  Intravenous administration of alteplase for patients with BAO appears to be associated with rates of survival, recanalization, and independent functional outcome comparable with those reported with endovascular approaches. These data suggest that a randomized trial is needed to compare these approaches for treatment of BAO.   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