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   4004篇
  免费   306篇
  国内免费   73篇
耳鼻咽喉   92篇
儿科学   90篇
妇产科学   14篇
基础医学   89篇
口腔科学   78篇
临床医学   1039篇
内科学   275篇
皮肤病学   7篇
神经病学   27篇
特种医学   71篇
外科学   1141篇
综合类   815篇
预防医学   147篇
眼科学   135篇
药学   267篇
  7篇
中国医学   43篇
肿瘤学   46篇
  2024年   5篇
  2023年   79篇
  2022年   113篇
  2021年   148篇
  2020年   152篇
  2019年   118篇
  2018年   152篇
  2017年   159篇
  2016年   124篇
  2015年   152篇
  2014年   297篇
  2013年   304篇
  2012年   290篇
  2011年   291篇
  2010年   241篇
  2009年   177篇
  2008年   147篇
  2007年   181篇
  2006年   155篇
  2005年   138篇
  2004年   114篇
  2003年   90篇
  2002年   90篇
  2001年   72篇
  2000年   67篇
  1999年   52篇
  1998年   45篇
  1997年   45篇
  1996年   36篇
  1995年   49篇
  1994年   56篇
  1993年   26篇
  1992年   23篇
  1991年   30篇
  1990年   22篇
  1989年   14篇
  1988年   15篇
  1987年   14篇
  1986年   9篇
  1985年   12篇
  1984年   23篇
  1983年   11篇
  1982年   10篇
  1981年   6篇
  1980年   13篇
  1978年   3篇
  1977年   8篇
  1975年   2篇
  1972年   1篇
  1967年   1篇
排序方式: 共有4383条查询结果,搜索用时 15 毫秒
1.
Transcranial Doppler (TCD) is an accepted modality for the evaluation of cerebral blood flow velocities. OBJECTIVES: The purpose of this study was to test the feasibility of bedside TCD measurement in the emergency department (ED) with critically ill, intubated patients. METHODS: A prospective convenience sample of patients presenting to a university hospital over a two-month period underwent TCD evaluation of the middle cerebral artery. Intubated patients with head trauma and any patient requiring tracheal intubation were eligible. A 2-MHz Doppler probe was positioned over the temporal bone to acquire blood flow velocities. An emergency medicine resident and research assistant obtained measurements. Continuous TCD tracings were recorded on a video cassette recorder tape for quality assurance review and data collection. Vital signs and therapeutic interventions were also recorded. Flow velocities were measured in cm/s; the peak Resistance Index (RI) was calculated for each patient. RESULTS: A total of 30 patients were enrolled in the study. Adequate tracings were obtained in 25 patients (83%) without a disruption of resuscitation. Tracings could not be obtained in five patients; they were listed as TCD failures. However, in two of these patients, adequate flow velocity tracings were obtained after resuscitation. Four patients were evaluated during tracheal intubation. One patient was monitored successfully during cardiopulmonary resuscitation. The median time required for data acquisition was 1.9 minutes. The mean highest RI for those who expired was 0.84. For those who survived, the mean highest RI was 0.52. The difference of 0.32 was statistically significant (p = 0.04). CONCLUSIONS: Noninvasive blood flow velocity monitoring of the middle cerebral artery using TCD is feasible in the ED when performed at the bedside on intubated patients with traumatic brain injury and others during tracheal intubation and resuscitation.  相似文献   
2.
Global coronary blood flow and metabolism were measured in seven patients on the first postoperative day following coronary revascularization to test the hypothesis that tracheal extubation produces adverse haemodynamic responses akin to those observed during tracheal intubation. Regional coronary flow and metabolic measurements were made in five of the seven patients. Extubation from a continuous positive airway pressure (CPAP) of 5 cm H2O was associated with a statistically significant rise in cardiac index from 3.44 ± 0.23 L · min-1 · m-2 to 3.73 ± 0.15L·min-1 ·m-2 related to an increase in stroke index, without significant changes in heart rate, mean arterial and pulmonary capillary wedge pressure. Consequently the changes in myocardial oxygen consumption (8.52 ± 0.55 to 8.85 ± 0.93 ml · min-1) and coronary blood flow (172 ± 18 to 179 ± 17 ml·min-1) were less prominent than those reported during intubation, where substantial rises in myocardial oxygen consumption and coronary flow occurred. Two patients experienced cardiac lactate production but there were no changes in systemic or coronary haemodynamics, nor were there clinical or electrocardiographic signs of ischaemia. We conclude that extubation does not appear to be associated with adverse systemic or coronary haemodynamic responses in patients following coronary bypass grafting. However, the revascularized myocardium may remain vulnerable to anaerobic metabolism in the immediate postoperative period. Pour savoir si comme ľintubation, ľextubation de la trachée provoque des perturbations hémodynamiques, on a mesuré le métabolisme et la circulation coronarienne globale chez sept patients, au lendemain ďun pontage aorto-coronarien. On a aussi calculé les valeurs régionales de ces mêmes variables pour cinq ďentre eux. Ľindex cardiaque de 3.44 ± 0.23 L · min-1 · m-2 sous pression positive en respiration spontanée (CPAP) de 5 cm. H2O s’est élevé à 3.73 ± 0.15 L · min-1 · m-2 post-extubation avec une augmentation significative du volume ďéjection. La fréquence cardiaque et les pressions artérielles moyennes et capillaires pulmonaires n’ont pas changé. Ainsi ľaugmentation de la consommation ďoxygène du myocarde de 8.52 ± 0.55 à 8.85 ± 0.93 ml · min-1 et celle du flot coronarien de 172 ± 18 à 179 ± 17 ml · min-1 ont été moindres que celles, importantes, déjà observées lors de ľintubation. On a noté chez deux patients une production de lactate par le myocarde, sans changement de ľhémodynamic systémique et coronarienne non plus que de signe clinique ou électrocardiographique ďischémie. Donc, après un pontage coronarien, ľextubation ne semble pas causer ďeffet néfaste sur les circulations systémique et coronarienne, toutefois, le myocarde revascularisé peut demeurer sensible au métabolisme anaérobique.  相似文献   
3.
4.
BACKGROUND: Caecal intubation is a necessary step in the complete endoscopic evaluation of the colon. Studies have estimated that experienced colonoscopists may fail to reach the caecum in up to 10% of cases. AIMS: To evaluate the utility of the double balloon enteroscope used for complete examination of the colon in patients with incomplete standard colonoscopy. PATIENTS: Twenty consecutive patients with incomplete colonoscopies within the Veterans Affairs Palo Alto Health Care System. Mean age of 66 years (S.D.+/-12 years, range 46-84), 16 men. METHODS: Prospective single-centre case series on the caecal intubation rate using standard double balloon enteroscope technique in patients with previous incomplete conventional colonoscopy. RESULTS: Use of the standard double balloon enteroscope technique permitted complete colonoscopy to be achieved in 95% of the patients (19/20). Seven patients (35%) had significant pathology beyond the extent of the prior incomplete colonoscopy. We performed endoscopic mucosal resection, polypectomy or biopsy. The mean time to reach the caecum was 28 min (S.D.+/-20 min, range 6-90 min). The sedation was similar to conventional colonoscopy. No complications occurred. CONCLUSIONS: The double balloon enteroscope technology and technique can be used to complete examination of the colon in patients who were referred because of incomplete standard colonoscopy.  相似文献   
5.
Three patients are described in whom it was impossible to visualise the larynx at direct laryngoscopy. Tracheal intubation was successfully and rapidly achieved with the aid of continuous fluoroscopy.  相似文献   
6.
Background : The study aimed to assess the relative influence of anaesthesia and muscle relaxation on intubating conditions and the haemodynamic and catecholamine responses to tracheal intubation.
Methods : Sixty ASA 1 or 2 patients were randomly assigned to one of four groups (15 patients each) that differed in the depth of anaesthesia (thiopentone plus fentanyl 2.5 μg kg-1 or thiopentone alone) and the degree of vecuronium–induced neuromuscular block (100% or _>: 65%) at intubation. Muscle relaxation was measured at 0.1 Hz by means of mechanomyography. Heart rate (HR) and mean arterial blood pressure (MAP) were measured before and after induction of anaesthesia, and 1 min and 5 min following intubation, while adrenaline (A) and noradrenaline concentrations (NA) were determined from arterial blood samples.
Results : Intubating conditions were improved primarily by providing complete muscle relaxation at the adductor pollicis muscle (P<0.001) and to a lesser extent by adding fentanyl to thiopentone (P=0.04). The response of HR and MAP to tracheal intubation was attenuated mainly by fentanyl (P<0.001). Complete muscle relaxation further diminished the response of MAP to intubation (P=0.03). Changes in A and NA were dependent on the depth of anaesthesia only (P =>0.01).
Conclusion : The results of the study demonstrate that the sympathoadrenal response to intubation is attenuated by adding fentanyl (2.5 kg-1) to an induction regimen with thiopentone, whereas provision of complete muscle relaxation at the adductor pollicis muscle is necessary to attain smooth intubating conditions.  相似文献   
7.
8.
162例气管插管患者的气道管理   总被引:16,自引:2,他引:14  
杨春娥 《护理学报》2004,11(1):20-21
笔者通过报道162例气管插管患者的气道管理,阐述痰痂形成的原因:(1)气道干燥,湿化不够。(2)吸痰管插入深度不够,吸痰不彻底。管理措施:(1)用金霉素眼膏润滑吸痰管,使之易于插入,保证吸痰管插入深度超过插管远端3-5cm。(2)预防气道干燥,注重湿化效果,重视吸痰环节。认为气囊不需定时放气,只需不定时调整气囊压力。  相似文献   
9.
老年卧床病人鼻饲并发症的护理干预   总被引:11,自引:0,他引:11  
目的 通过护理干预 (增加置入胃管深度、抬高床头、适宜鼻饲量及鼻饲速度 )预防鼻饲时出现的呛咳、食物反流、胃潴留以及吸入性肺炎。方法 将 16例老年卧床鼻饲患者随机分成四组 ,对照组给予教科书上常规的置管深度及鼻饲方法 ;实验一组 (A)给予常规置管深度 ,鼻饲时抬高床头 30~ 80cm ;实验二组 (B)置管深度延长 8~ 10cm ,实验三组 (C)置管深度延长8~ 10cm ,鼻饲时抬高床头 30~ 80cm(坐位或半坐位 ) ,保持该体位 30min。结果 四组病人比较呛咳 ,对照组与实验组 (A、B、C)P <0 .0 1,差异有统计学意义 ;食物返流率P <0 .0 5 ;胃潴留对照组与实验组P >0 .0 5 ,差异无统计学意义 ;吸入性肺炎对照组 2例 ,A、B组各 1例 ,C组无发生。结论 护理干预可以减少与预防鼻饲并发症的发生。  相似文献   
10.
老年病人鼻饲方法的改进   总被引:16,自引:2,他引:14  
目的探讨增加置管深度并抬高床头对预防老年鼻饲病人食物反流的效果。方法将 5 75例需鼻饲的卧床老年病人按鼻饲医嘱时间顺序及不平衡指数最小原则分成三组 ,分别给予教科书中的常规置管深度置管 (对照组 )、置管深度延长 10cm(观察 1组 )、置管深度延长 10cm并抬高床头 30~ 45°(观察 2组 )进行鼻饲。结果三组病人食物反流率比较 ,P <0 .0 1;观察 1、2组分别与对照组比较 ,P <0 .0 5、P <0 .0 1;观察 1组与观察 2组比较 ,P <0 .0 1。增加置管深度并抬高床头其食物反流率最低 ,仅增加置管深度次之 ,常规置管最高。结论增加置管深度并抬高床头可显著降低老年鼻饲病人食物反流发生率。  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