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   2247篇
  免费   288篇
  国内免费   5篇
耳鼻咽喉   45篇
儿科学   68篇
妇产科学   21篇
基础医学   237篇
口腔科学   175篇
临床医学   328篇
内科学   493篇
皮肤病学   49篇
神经病学   181篇
特种医学   34篇
外科学   287篇
综合类   27篇
一般理论   1篇
预防医学   279篇
眼科学   22篇
药学   137篇
肿瘤学   156篇
  2024年   3篇
  2023年   49篇
  2022年   21篇
  2021年   43篇
  2020年   44篇
  2019年   46篇
  2018年   77篇
  2017年   70篇
  2016年   64篇
  2015年   74篇
  2014年   115篇
  2013年   131篇
  2012年   152篇
  2011年   164篇
  2010年   109篇
  2009年   107篇
  2008年   116篇
  2007年   171篇
  2006年   121篇
  2005年   130篇
  2004年   148篇
  2003年   137篇
  2002年   123篇
  2001年   18篇
  2000年   15篇
  1999年   26篇
  1998年   35篇
  1997年   34篇
  1996年   24篇
  1995年   24篇
  1994年   16篇
  1993年   16篇
  1992年   13篇
  1991年   7篇
  1990年   8篇
  1989年   8篇
  1988年   7篇
  1987年   8篇
  1985年   6篇
  1984年   7篇
  1983年   5篇
  1982年   8篇
  1981年   3篇
  1980年   8篇
  1979年   3篇
  1978年   4篇
  1976年   6篇
  1966年   3篇
  1960年   2篇
  1936年   2篇
排序方式: 共有2540条查询结果,搜索用时 774 毫秒
81.

Background

Traumatic brain injury is common. Guidelines from the Brain Trauma Foundation and the Scottish Intercollegiate Guidelines Network recommend that patients with suspected severe traumatic brain injury should be treated in centres with neurosurgical expertise. Scotland does not have a framework for the delivery of trauma care. The aim of this study was to examine the demographic characteristics of incidents involving patients who have suffered a suspected traumatic brain injury, and to evaluate the level of the destination healthcare facility which patients are currently taken to.

Methods

Retrospective analysis of prospectively collected Scottish Ambulance Service data on incidents involving traumatic injury, between Nov 2008 and Oct 2010. Two groups of casualties were analysed: those who had a Glasgow coma scale of less than 14 (GCS < 14), and those who had a Glasgow coma scale of less than 9 (GCS < 9).

Results

126,934 incidents were identified and analysed. 3890 (3.1%) patients had a GCS of less than 14, and 657 (0.5% of total) had a GCS of less than 9. Almost one-third of incidents involving patients with either a GCS < 14 or GCS < 9 occurred in the greater Glasgow health board area. The Lothian health board region had the second-highest number of patients with either a GCS < 14 or GCS < 9. Only 13.8% of patients with a GCS < 14, and 16.7% of those with a GCS < 9, were taken to a hospital with a neurosurgical service.

Conclusions

Many patients who may harbour a traumatic brain injury are taken to a facility which may not be equipped or staffed to deal with such injuries. This mismatch needs to be addressed. However, the care of patients with head injuries is only one aspect of trauma care. The UK has long lagged behind North America in terms of the quality of trauma care provided, although the provision of trauma care in England is currently undergoing major changes. Scotland should consider the development of a similar service delivery framework.  相似文献   
82.
口咽通气导管为一种非气管导管性通气管道,其操作简便,易于掌握,不需要特殊器械能在数秒钟内迅速获得有效通气,并保持呼吸道通畅,在抢救危重、昏迷患者过程中发挥着重要的作用[1].但传统口咽通气导管使用中因不易固定,容易全部滑入患者口腔,有并发食管、气管异物,引起患者误吸、窒息甚至危及患者生命的危险[2].为此,我科对传统口咽通气导管进行改良,介绍如下.  相似文献   
83.

Introduction

The influence that different concentrations of labour epidural local anesthetic have on assisted vaginal delivery (AVD) and many obstetric outcomes and side effects is uncertain. The purpose of this meta-analysis was to determine whether local anesthetics utilized at low concentrations (LCs) during labour are associated with a decreased incidence of AVD when compared with high concentrations (HCs).

Methods

We searched PubMed, Ovid EMBASE, Ovid MEDLINE, CINAHL, Scopus, clinicaltrials.gov, and Cochrane databases for randomized controlled trials of labouring patients that compared LCs (defined as ≤ 0.1% epidural bupivacaine or ≤ 0.17% ropivacaine) of epidural local anesthetic with HCs for maintenance of analgesia. The primary outcome was AVD and secondary outcomes included Cesarean delivery, duration of labour, analgesia, side effects (nausea and vomiting, motor block, hypotension, pruritus, and urinary retention), and neonatal outcomes. The odds ratios (OR) or weighted mean differences (WMD) and 95% confidence intervals (CI) were calculated using random effects modelling. An OR < 1 or a WMD < 0 favoured LCs.

Results

Eleven studies met our criteria (eight bupivacaine and three ropivacaine studies), providing 1,145 patients in the LCs group and 852 patients in the HCs group for analysis of the primary outcome. Low concentrations were associated with a reduction in the incidence of AVD (OR = 0.70; 95% CI 0.56 to 0.86; P < 0.001). There was no difference in the incidence of Cesarean delivery (OR 1.05; 95% CI 0.82 to 1.33; P = 0.7). The LCs group had less motor block (OR 3.9; 95% CI 1.59 to 9.55; P = 0.003), greater ambulation (OR 2.8; 95% CI 1.1 to 7.14; P = 0.03), less urinary retention (OR 0.42; 95% CI 0.23 to 0.73; P = 0.002), and a shorter second stage of labour (WMD ?14.03; 95% CI ?27.52 to ?0.55; P = 0.04) compared with the HCs group. There were no differences between groups in pain scores, maternal nausea and vomiting, hypotension, fetal heart rate abnormalities, five-minute Apgar scores, and need for neonatal resuscitation. One-minute Apgar scores < 7 favoured the HCs group (OR 1.53; 95% CI 1.07 to 2.21; P = 0.02), and there was more pruritus in the LCs group (OR 3.36; 95% CI 1.00 to 11.31; P = 0.05).

Conclusion

When compared with HCs of local anesthetics, the use of LCs for labour epidural analgesia reduces the incidence of AVD. This may be due to a reduction in the amount of local anesthetic used and the subsequent decrease in motor blockade. We therefore recommend the use of LCs of local anesthetics for epidural analgesia to optimize obstetric outcome.  相似文献   
84.

Background

Previously active in the mid-1990s, the Canadian Airway Focus Group (CAFG) studied the unanticipated difficult airway and made recommendations on management in a 1998 publication. The CAFG has since reconvened to examine more recent scientific literature on airway management. The Focus Group’s mandate for this article was to arrive at updated practice recommendations for management of the unconscious/induced patient in whom difficult or failed tracheal intubation is encountered.

Methods

Nineteen clinicians with backgrounds in anesthesia, emergency medicine, and intensive care joined this iteration of the CAFG. Each member was assigned topics and conducted reviews of Medline, EMBASE, and Cochrane databases. Results were presented and discussed during multiple teleconferences and two face-to-face meetings. When appropriate, evidence- or consensus-based recommendations were made together with assigned levels of evidence modelled after previously published criteria.

Conclusions

The clinician must be aware of the potential for harm to the patient that can occur with multiple attempts at tracheal intubation. This likelihood can be minimized by moving early from an unsuccessful primary intubation technique to an alternative “Plan B” technique if oxygenation by face mask or ventilation using a supraglottic device is non-problematic. Irrespective of the technique(s) used, failure to achieve successful tracheal intubation in a maximum of three attempts defines failed tracheal intubation and signals the need to engage an exit strategy. Failure to oxygenate by face mask or supraglottic device ventilation occurring in conjunction with failed tracheal intubation defines a failed oxygenation, “cannot intubate, cannot oxygenate” situation. Cricothyrotomy must then be undertaken without delay, although if not already tried, an expedited and concurrent attempt can be made to place a supraglottic device.  相似文献   
85.
The profession of dental therapy has long been held up as a model for reducing access to care barriers in high-risk, underserved populations worldwide. Dental therapists practice in many countries delivering preventive and basic restorative care to children and adults. In North America, dental therapy education and practice date back to 1972 with the establishment of training programs at the National School of Dental Therapy in Fort Smith, Northwest Territories, and the Wascana Institute of Applied Arts and Science in Regina, Saskatchewan, as a means of reducing access to care barriers in Canada's northern territories and to implement the Saskatchewan Health Dental Plan, respectively. At present, dental therapy in North America has reached a crossroads: in the United States, the profession is cautiously being explored as a solution for improving access to care in at-risk populations. In 2011, Canada's sole training program, the National School of Dental Therapy in Prince Albert, Saskatchewan, closed when the federal government eliminated its funding. This article examines the impact of private practice employment of dental therapists in Saskatchewan on the supply of dental therapist human resources for health in Canada's three northern territories (Northwest Territories, Nunavut, and Yukon), its role in the closure of the National School of Dental Therapy in 2011, and ramifications for the future of dental therapy in Canada.  相似文献   
86.
Implant-supported overdentures are a good alternative for patients with conventional dentures that lack retention and stability. The most common prosthetic complications in mandibular and maxillary implant-supported overdentures are fracture and loosening of the attachment system. This clinical report describes the treatment of a completely edentulous patient with sinus floor elevation by using bone from the iliac crest and the insertion of 4 implants in the maxilla and mandible followed by implant-supported overdentures. The technical procedure for the attachment of clips to an acrylic resin overdenture base with the use of metal reinforcement is described. The advantage of this attachment procedure is an improved attachment system with less fracture and less loosening of the clips.  相似文献   
87.
88.
Background: Despite the widespread use of the Impact of Event Scale to measure post-traumatic stress symptoms, psychometric evaluations of the scale have revealed mixed findings. Aim: The aim of the present study is to provide new empirical evidence and examine the factor structure, reliability, and predictive validity of the Norwegian version of the IES-R. Methods: Posttraumatic stress symptoms were recorded in a student sample (n=312) 3 weeks after the Southeast Asian tsunami disaster in December 2004. Confirmatory factor analyses of the IES-R behavior items using structural equation modeling (SEM) were performed on four models from existing research. Results: The original three-factor model of intrusion, avoidance and hyperarousal symptoms exhibited the best goodness-of-fit indices when defined as oblique. The IES-R also revealed satisfactory reliability. Symptom levels of intrusion and avoidance were moderate, while hyperarousal scores were low, with a significant gender difference. Conclusion: Taken together, the IES-R revealed good psychometric properties in this nonclinical student sample and could be a useful instrument to assess and follow-up on PTSD symptoms after a certain identified trauma.  相似文献   
89.
90.
Introduction: Animal toxicity studies used to assess the safety of new candidate pharmaceuticals prior to their progression into human clinical trials are unable to assess the risk of non-pharmacologically mediated idiosyncratic adverse drug reactions (ADRs), the most frequent of which are drug-induced liver injury and cardiotoxicity. Idiosyncratic ADRs occur only infrequently and in certain susceptible humans, but are caused by many hundreds of different drugs and may lead to serious illness.

Areas covered: Idiosyncratic ADRs are initiated by drug-related chemical insults, which cause toxicity due to susceptibility factors that manifest only in certain patients. The chemical insults can be detected using in vitro assays. These enable useful discrimination between drugs that cause high versus low levels of idiosyncratic ADR concern. Especially promising assays, which have been described recently in peer-reviewed scientific literature, are highlighted.

Expert opinion: Effective interpretation of in vitro toxicity data requires integration of endpoints from multiple assays, which each address different mechanisms, and must also take account of human systemic and tissue drug exposure in vivo. Widespread acceptance and use of such assays has been hampered by the lack of correlation between idiosyncratic human ADR risk and toxicities observed in vivo in animals.  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