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   18426篇
  免费   1162篇
  国内免费   148篇
耳鼻咽喉   154篇
儿科学   375篇
妇产科学   263篇
基础医学   2324篇
口腔科学   561篇
临床医学   1875篇
内科学   3976篇
皮肤病学   383篇
神经病学   2357篇
特种医学   1282篇
外科学   2846篇
综合类   92篇
一般理论   7篇
预防医学   592篇
眼科学   408篇
药学   977篇
中国医学   13篇
肿瘤学   1251篇
  2023年   149篇
  2022年   145篇
  2021年   468篇
  2020年   348篇
  2019年   409篇
  2018年   500篇
  2017年   440篇
  2016年   569篇
  2015年   635篇
  2014年   794篇
  2013年   915篇
  2012年   1449篇
  2011年   1439篇
  2010年   950篇
  2009年   872篇
  2008年   1300篇
  2007年   1415篇
  2006年   1190篇
  2005年   1204篇
  2004年   1147篇
  2003年   1054篇
  2002年   941篇
  2001年   163篇
  2000年   127篇
  1999年   165篇
  1998年   137篇
  1997年   112篇
  1996年   88篇
  1995年   72篇
  1994年   65篇
  1993年   64篇
  1992年   46篇
  1991年   37篇
  1990年   23篇
  1989年   34篇
  1988年   39篇
  1987年   20篇
  1986年   24篇
  1985年   22篇
  1984年   16篇
  1983年   19篇
  1982年   14篇
  1981年   8篇
  1980年   11篇
  1979年   12篇
  1978年   17篇
  1977年   15篇
  1975年   7篇
  1974年   7篇
  1972年   7篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
2.
Dambach  Micha  Fieber  Jakob  Wanzenried  Manuel  Fehr  Tobias  Konrad  Christoph  Goertz  Roland  Fieber  David 《Der Anaesthesist》2022,71(11):846-851
Die Anaesthesiologie - Die Anwendung von hohen Sauerstoffkonzentration birgt Gefahren für Patienten und Anwender. Hohe Umgebungskonzentrationen an Sauerstoff bergen die Gefahr von...  相似文献   
3.
4.

A positive relationship between treatment volume and outcome quality has been demonstrated in the literature and is thus evident for a variety of procedures. Consequently, policy makers have tried to translate this so-called volume–outcome relationship into minimum volume regulation (MVR) to increase the quality of care—yet with limited success. Until today, the effect of strict MVR application remains unclear as outcome quality gains cannot be estimated adequately and restrictions to application such as patient travel time and utilization of remaining hospital capacity are not considered sufficiently. Accordingly, when defining MVR, its effectiveness cannot be assessed. Thus, we developed a mixed integer programming model to define minimum volume thresholds balancing utility in terms of outcome quality gain and feasibility in terms of restricted patient travel time and utilization of hospital capacity. We applied our model to the German hospital sector and to four surgical procedures. Results showed that effective MVR needs a minimum volume threshold of 125 treatments for cholecystectomy, of 45 and 25 treatments for colon and rectum resection, respectively, of 32 treatments for radical prostatectomy and of 60 treatments for total knee arthroplasty. Depending on procedure type and incidence as well as the procedure’s complication rate, outcome quality gain ranged between 287 (radical prostatectomy) and 977 (colon resection) avoidable complications (11.7% and 11.9% of all complications). Ultimately, policy makers can use our model to leverage MVR’s intended benefit: concentrating treatment delivery to improve the quality of care.

  相似文献   
5.

Purpose

Many authors suggest that extremity soft tissue sarcomas (ESTS) do not change significantly in size during preoperative radiation therapy (RT). This cone beam computed tomography study investigates the justification to deliver the entire course with 1 initial RT plan by observing anatomic changes during RT.

Methods and Materials

Between 2015 and 2017, 99 patients with ESTS were treated with either curative (n = 80) or palliative intent (n = 19) with a regimen of at least 6 fractions. The clinical target volume to planning target volume margin was 1 cm. Action levels were assigned by radiation technicians. An extremity contour change of >1 cm and/or tumor size change >0.5 cm required a physician's action before the next fraction.

Results

A total of 982 cone beam computed tomography logfiles were studied. In 41 of 99 patients, the dose coverage of the initial treatment plan was fully satisfactory throughout the RT course. However, action levels were observed in 58 patients (59%). In 41 of these 58 patients, a contour increase of 5 to 23 mm was noted (29 tumor size increase only, 3 extremity contour increase, and 9 both). In 21 of 58 patients, a decrease of 5 to 33 mm was observed (20 tumor size decrease only and 1 tumor size decrease and extremity contour decrease). In 4 cases, contours initially increased and subsequently decreased. In 33 of 41 patients with increasing contours, the dose distribution adequately covered gross tumor volume because of the 1 cm planning target volume margin applied. For the remaining 8 patients (8%), the plan needed to be adapted.

Conclusions

ESTS volumes may change substantially during RT in 59% of all patients, leading to plan adaptations resulting from increased volumes in 8%. Daily critical observation of these patients is mandatory to avoid geographic misses because of increases in size and overdosing of normal tissues when masses shrink.  相似文献   
6.
7.
Die Anaesthesiologie - Die Implementierung eines Patient Blood Management (PBM) wird zunehmender Standard in der operativen Medizin. Seit einiger Zeit gilt das Interesse auch den vulnerablen...  相似文献   
8.
Guidelines recommend cognitive behavioural therapy for insomnia (CBT‐I) as first‐line treatment for chronic insomnia, but it is not clear how many primary care physicians (PCPs) in Switzerland prescribe this treatment. We created a survey that asked PCPs how they would treat chronic insomnia and how much they knew about CBT‐I. The survey included two case vignettes that described patients with chronic insomnia, one with and one without comorbid depression. PCPs also answered general questions about treating chronic insomnia and about CBT‐I and CBT‐I providers. Of the 820 Swiss PCPs we invited, 395 (48%) completed the survey (mean age 54 years; 70% male); 87% of PCPs prescribed sleep hygiene and 65% phytopharmaceuticals for the patient who had only chronic insomnia; 95% prescribed antidepressants for the patient who had comorbid depression. In each case, 20% of PCPs prescribed benzodiazepines or benzodiazepine receptor agonists, 8% prescribed CBT‐I, 68% said they knew little about CBT‐I, and 78% did not know a CBT‐I provider. In the clinical case vignettes, most PCPs treated chronic insomnia with phytopharmaceuticals and sleep hygiene despite their lack of efficacy, but PCPs rarely prescribed CBT‐I, felt they knew little about it, and usually knew no CBT‐I providers. PCPs need more information about the benefits of CBT‐I and local CBT‐I providers and dedicated initiatives to implement CBT‐I in order to reduce the number of patients who are prescribed ineffective or potentially harmful medications.  相似文献   
9.
10.

Background

Arousal and sleep represent basic domains of behavior, and alterations are of high clinical importance.

Objective/hypothesis

The aim of this study was to further elucidate the neurobiology of insomnia disorder (ID) and the potential for new treatment developments, based on the modulation of cortical activity through the non-invasive brain stimulation technique transcranial direct current stimulation (tDCS). Specifically, we tested the hypotheses that bi-frontal anodal tDCS shortens and cathodal tDCS prolongs total sleep time in patients with ID, compared to sham stimulation. Furthermore, we tested for differences in indices of arousal between ID patients and healthy controls and explored their potential impact on tDCS effects.

Methods

Nineteen ID patients underwent a within-subject repeated-measures sleep laboratory study with adaptation, baseline and three experimental nights. Bifrontal anodal, cathodal and sham tDCS was delivered in a counterbalanced order immediately prior to sleep. Wake EEG was recorded prior to and after tDCS as well as on the following morning. Subsequently, we compared patients with ID to a healthy control group from an earlier dataset.

Results

Against our hypothesis, we did not observe any tDCS effects on sleep continuity or sleep architecture in patients with ID. Further analyses of nights without stimulation demonstrated significantly increased levels of arousal in ID patients compared to healthy controls, as indexed by subjective reports, reduced total sleep time, increased wake after sleep onset and increased high frequency EEG power during wakefulness and NREM sleep. Of note, indices of increased arousal predicted the lack of effect of tDCS in ID patients.

Conclusions

Our study characterizes for the first time differential effects of tDCS on sleep in patients with ID and healthy controls, presumably related to persistent hyperarousal in ID. These findings suggest that adapted tDCS protocols need to be developed to modulate arousal and sleep dependent on baseline arousal levels.  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