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   460篇
  免费   44篇
耳鼻咽喉   13篇
儿科学   31篇
妇产科学   8篇
基础医学   100篇
口腔科学   22篇
临床医学   35篇
内科学   57篇
皮肤病学   6篇
神经病学   26篇
特种医学   4篇
外科学   51篇
综合类   13篇
预防医学   44篇
眼科学   5篇
药学   66篇
中国医学   1篇
肿瘤学   22篇
  2022年   5篇
  2021年   8篇
  2020年   14篇
  2019年   11篇
  2018年   13篇
  2017年   6篇
  2016年   3篇
  2015年   14篇
  2014年   19篇
  2013年   16篇
  2012年   22篇
  2011年   30篇
  2010年   7篇
  2009年   8篇
  2008年   20篇
  2007年   21篇
  2006年   12篇
  2005年   17篇
  2004年   18篇
  2003年   17篇
  2002年   14篇
  2001年   4篇
  2000年   14篇
  1999年   9篇
  1998年   6篇
  1997年   3篇
  1996年   5篇
  1994年   8篇
  1993年   6篇
  1992年   9篇
  1991年   8篇
  1990年   5篇
  1989年   9篇
  1988年   10篇
  1987年   7篇
  1986年   8篇
  1985年   10篇
  1984年   6篇
  1983年   8篇
  1982年   4篇
  1981年   5篇
  1979年   3篇
  1975年   4篇
  1974年   8篇
  1973年   10篇
  1972年   3篇
  1970年   5篇
  1967年   3篇
  1966年   4篇
  1960年   2篇
排序方式: 共有504条查询结果,搜索用时 15 毫秒
31.
32.
Inhalation of foreign body into the tracheobronchial tree is a medical emergency sometimes resulting into sudden death. The current mortality rate due to foreign body inhalation ranges from 0% to 1.8%. Children with or without positive history of aspiration were examined and diagnosis was made on the basis of history, clinical findings, radiological evaluation and strong index of suspicion. A review of 30 cases of suspected foreign body aspiration revealed, children between 6 months were found to be very vulnerable to aspiration. Majority of children were boys. 80% of the patients had positive history of inhalation. Only 50% of the patients presented immediately i.e. within 24 hours after aspiration. Common symptoms were cough and respiratory distress. Decreased air entry was the significant clinical sign (50%). Obstructive emphysema and mediastinal shift were found in the majority of cases (50%). Rigid bronchoscopy under general anaesthesia and patient ventilating using a jet ventilator is a very safe and effective technique.  相似文献   
33.
Despite the improvements in the pharmacological treatment of acute myocardial infarction, it is recognised that thrombolysis fails to reproduce reperfusion in a significant proportion of patients. Coronary interventional techniques have been shown to offer an alternative reperfusion strategy. There is increasing evidence that mechanical reperfusion may offer significant advantages over established thrombolytic therapy.  相似文献   
34.
1. The natural product willardiine is an AMPA receptor agonist. We have examined the structural changes required to convert willardiine into an antagonist at AMPA and kainate receptors. Structure-activity analysis has been carried out to discover the structural features required to increase the potency and/or selectivity of the antagonists at AMPA or kainate receptors. 2. Reduction of the fast component of the dorsal root-evoked ventral root potential (fDR-VRP) has been used to investigate AMPA receptor antagonist activity. To examine antagonist activity at kainate receptors, the ability of compounds to depress kainate-induced depolarisations of dorsal root fibres was assessed. 3. Blocking ionisation of the uracil ring by adding a methyl group to the N(3) position was not sufficient to convert willardiine into an antagonist. However, willardiine derivatives with a side-chain bearing a carboxylic acid group at the N(3)-position of the uracil ring could antagonise AMPA and kainate receptors. 4. S stereochemistry was optimal for antagonism. When compounds with differing interacidic group chain lengths were compared, a group chain length of two methylene groups was preferable for AMPA receptor antagonism in the series of compounds bearing a carboxyalkyl side chain (UBP275, UBP277 and UBP279 reduced the fDR-VRP with IC(50) values of 287+/-41, 23.8+/-3.9 and 136+/-17 micro M, respectively). For kainate receptor antagonism, two or three methylene groups were almost equally acceptable (UBP277 and UBP279 reduced dorsal root kainate responses with apparent K(D) values of 73.1+/-4.5 and 60.5+/-4.1 micro M, respectively). 5. Adding an iodo group to the 5-position of UBP277 and UBP282 enhanced activity at kainate receptors (UBP291 and UBP301 antagonised kainate responses on the dorsal root with apparent K(D) values of 9.83+/-1.62 and 5.94+/-0.63 micro M, respectively). 6. The most useful antagonist identified in this study was UBP301, which was a potent and approximately 30-fold selective kainate receptor antagonist. UBP282 may also be of use in isolating a non-GluR5-mediated kainate response.  相似文献   
35.
Obesity is a pathologic entity characterized by an increase in fat body mass and is a global public health problem. In Spain, between 1984 (the Paidos study) and 2000 (the enKid study), the prevalence of childhood overweight and obesity increased and significant differences were found among the autonomous communities. Consequently prophylactic measures were implemented throughout the country and in 2005 the Ministry of Health developed the NAOS strategy (strategy for nutrition, physical activity and obesity prevention). Within the medical area of this intervention, primary care pediatricians acquire a key role. Aware of this, the Spanish Association of Pediatrics, through the Nutrition Committee, aims to provide information on the current situation concerning the etiopathogenesis and early identification of at-risk populations. The epidemiology and risk periods in the pediatric age group are reviewed and recommendations on healthy lifestyle are provided, bearing in mind diet and physical activity throughout childhood, with the aim of preventing overweight and obesity.  相似文献   
36.
Anti-thrombotic therapy for non-rheumatic atrial fibrillation   总被引:1,自引:0,他引:1  
Recent randomized trials of antithrombotic therapy in non-rheumatic atrial fibrillation have helped to clarify the benefits of warfarin and aspirin. Low-risk patients (normotensives aged <60 with normal left ventricular function) have a small risk of thromboembolic events and are unlikely to benefit significantly from anticoagulants, but may benefit from aspirin with little increase in risk of bleeding. High-risk patients (>75 years, impaired left ventricular function, previous thromboembolism and/or associated conditions such as hypertension and diabetes mellitus) have an increased risk of thromboembolism, and benefit from long-term anticoagulant therapy to a greater degree than with aspirin, although at a risk of increased bleeding complications.   相似文献   
37.
The present study was carried out to elucidate the beneficial effect of pioglitazone in cognitive impairment induced by bilateral infusion of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in substantia nigra pars compacta (SNc) in rats, a model of Parkinson's disease. MPTP-lesioned rats showed poor cognitive performance in both passive avoidance task and cued version of the Morris water maze test. This deficit in learning and memory was found to be associated with oxidative stress. Chronic administration of pioglitazone (10 and 30 mg/kg, p.o., starting 5 days prior to MPTP administration and then for next 30 days) in MPTP-lesioned rats improved cognitive performance in passive avoidance task and cued version of the Morris water maze test. Furthermore, pioglitazone treatment also reduced oxidative stress (as evident by reduced malondialdehyde and increased glutathione levels). These results demonstrate the beneficial effects of pioglitazone on cognitive impairment in MPTP induced Parkinson's disease in rats.  相似文献   
38.
To study the outcomes of split electrode array cochlear implantation in ossified cochlea using the CAP scoring system. Retrospective case study. Tertiary referral center. Six cochleae in three adult and three pediatric patients with ossification. Intervention(s): All Patients underwent cochlear implantation with a split electrode array system. Major outcome parameter(s): Number of electrodes inserted during surgery, number of functioning electrodes on follow-up and auditory performance evaluation using the CAP score—Category of Auditory Perception [TSC Revised Version, based on Nottingham CI Program, 1995]. Six patients (three children and three adults) had insertion of split electrode array system. The mean number of electrodes inserted were 18.3 (range 15–21) and functioning electrodes at follow-up were mean of 14.3 (range 7–21). Auditory performance was measured using CAP score at 1 year post implant follow up, mean score in children was six and that in adult was eight. One pt had facial nerve twitching which was corrected by switching off the concerned electrode. No complications in sort of facial palsy or vestibular disorder were observed. Patients of ossified cochlea having profound deafness do well with split electrode array cochlear implantation as evaluated with CAP scoring system. The split electrode array results in more number of electrodes within the cochlear lumen. Retro graded apical array insertion has less chances of facial nerve stimulation as it is placed away from the nerve.  相似文献   
39.
On the basis of harmine and 1-methoxy-canthin-6-one chemical structures, a series of novel 1,4-disubstituted and 1,4,9-trisubstituted β-carbolines and tetracyclic derivatives were designed and synthesized. Cytotoxic activities of these compounds in vitro were investigated in a human tumor cell line panel. Almost all compounds demonstrated interesting cytotoxic activities in particular against prostate cancer cells PC-3 with IC50 in the low micromolar range. Compound X was found to be the most potent one with IC50 value of 8.0 μM; this suggests further studies with models of prostate cancer.  相似文献   
40.

Background  

Aggregate urban health statistics mask inequalities. We described maternity care in vulnerable slum communities in Mumbai, and examined differences in care and outcomes between more and less deprived groups.  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