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   335篇
  免费   32篇
耳鼻咽喉   1篇
儿科学   5篇
基础医学   42篇
口腔科学   3篇
临床医学   23篇
内科学   38篇
皮肤病学   3篇
神经病学   28篇
特种医学   46篇
外科学   112篇
综合类   5篇
预防医学   7篇
眼科学   3篇
药学   21篇
肿瘤学   30篇
  2023年   4篇
  2022年   5篇
  2021年   12篇
  2020年   8篇
  2019年   11篇
  2018年   12篇
  2017年   1篇
  2016年   16篇
  2015年   18篇
  2014年   17篇
  2013年   20篇
  2012年   41篇
  2011年   32篇
  2010年   19篇
  2009年   18篇
  2008年   29篇
  2007年   19篇
  2006年   12篇
  2005年   6篇
  2004年   6篇
  2003年   12篇
  2002年   15篇
  2001年   5篇
  2000年   1篇
  1999年   3篇
  1998年   3篇
  1993年   1篇
  1990年   2篇
  1988年   2篇
  1982年   1篇
  1981年   1篇
  1979年   1篇
  1977年   3篇
  1974年   4篇
  1973年   2篇
  1971年   2篇
  1970年   1篇
  1967年   1篇
  1965年   1篇
排序方式: 共有367条查询结果,搜索用时 15 毫秒
171.
Lymphocytic hypophysitis is an uncommon autoimmune condition that often results in significant morbidity. Although most cases resolve spontaneously or after a short course of steroids, rarely, refractory cases can cause persistent neurological deficits despite aggressive medical and surgical management. A 41-year-old woman presented with progressive visual loss in the left eye and was found to have a sellar mass. She underwent transsphenoidal surgery because of lesion enlargement. Histopathology was consistent with adenohypophysitis with B-cell predominance. Despite steroid treatment, her neurological condition worsened and she experienced loss of vision in the right eye. Craniotomy with decompression of the right optic nerve was performed. Her condition improved initially, but she continued to have progressive visual compromise over the following months. She was therefore treated with rituximab, a monoclonal antibody against B cells. Her vision improved significantly within a few weeks. There was no clinical or radiographic exacerbation 2 years after starting immunotherapy. Rituximab, an anti-CD20 antibody that specifically depletes B lymphocytes, can be an effective treatment strategy for patients with steroid-refractory, B cell-predominant lymphocytic hypophysitis.  相似文献   
172.
We conducted a randomised trial comparing the self‐pressurised air‐QTM intubating laryngeal airway (air‐Q SP) with the LMA‐Unique in 60 children undergoing surgery. Outcomes measured were airway leak pressure, ease and time for insertion, fibreoptic examination, incidence of gastric insufflation and complications. Median (IQR [range]) time to successful device placement was faster with the air‐Q SP (12 (10–15 [5–18])) s than with the LMA‐Unique (14 (12–17 [6–22]) s; p = 0.05). There were no statistically significant differences between the air‐Q SP and LMA‐Unique in initial airway leak pressures (16 (14–18 [10–29]) compared with 18 (15–20 [10–30]) cmH2O, p = 0.12), an airway leak pressures at 10 min (19 (16–22 [12–30]) compared with 20 (16–22 [10–30]) cmH2O, p = 0.81); fibreoptic position, incidence of gastric insufflation, or complications. Both devices provided effective ventilation without the need for airway manipulation. The air‐Q SP is an alternative to the LMA‐Unique should the clinician prefer a device not requiring cuff monitoring during anaesthesia.  相似文献   
173.

Purpose

This article is a review of the efficacy and safety of the Laryngeal Mask Airway (LMA) Supreme? as a stand-alone supraglottic airway during general anesthesia and as a conduit for tracheal intubation. Relevant articles were obtained using MEDLINE (1948-July 2011) and EMBASE (1980-July 2011). Only original studies with adult human patients and published in English were selected.

Principal findings

The LMA Supreme was found to be comparable with the LMA Proseal? with regard to success rate, insertion time, and complications. However, in three studies, oropharyngeal leak pressure was higher with the LMA Proseal than with the LMA Supreme. The LMA Supreme was superior to the LMA Classic? with regard to insertion time and oropharyngeal seal pressure. The LMA Supreme was also used successfully in two difficult airway cases, and it has been used as a conduit for tracheal intubation by utilizing an intubation introducer (gum elastic bougie) and subsequently railroading an endotracheal tube over the bougie into the trachea. Techniques for achieving tracheal intubation include the use of the Aintree Intubation Catheter?, a guidewire-exchange catheter, a gum elastic bougie, and a small (<6.0?mm internal diameter) endotracheal tube.

Conclusion

The LMA Supreme has been shown to be a safe and efficacious device as a stand-alone supraglottic airway and may also be used as a conduit for tracheal intubation. Further trials are needed to determine the efficacy of the LMA Supreme compared with other supraglottic airways in both elective and emergent airway management situations.  相似文献   
174.
Introduction: Existing screening investigations for the diagnosis of early prostate cancer lack specificity, resulting in a high negative biopsy rate. There is increasing interest in the use of various magnetic resonance methods for improving the yield of transrectal ultrasound‐guided biopsies of the prostate in men suspected to have prostate cancer. We review the existing status of such investigations. Methods: A literature search was carried out using the Pubmed database to identify articles related to magnetic resonance methods for diagnosing prostate cancer. References from these articles were also extracted and reviewed. Results: Recent studies have focused on prebiopsy magnetic resonance investigations using conventional magnetic resonance imaging, dynamic contrast enhanced magnetic resonance imaging, diffusion weighted magnetic resonance imaging, magnetization transfer imaging and magnetic resonance spectroscopy of the prostate. This marks a shift from the earlier strategy of carrying out postbiopsy magnetic resonance investigations. Prebiopsy magnetic resonance investigations has been useful in identifying patients who are more likely to have a biopsy positive for malignancy. Conclusions: Prebiopsy magnetic resonance investigations has a potential role in increasing specificity of screening for early prostate cancer. It has a role in the targeting of biopsy sites, avoiding unnecessary biopsies and predicting the outcome of biopsies.  相似文献   
175.
Objectives: To assess the clinical performance of the laryngeal mask airway‐Supreme in children. Aim: The purpose of this prospective audit was to evaluate the feasibility of the laryngeal mask airway‐Supreme in clinical practice and generate data for future comparison trials. Background: The laryngeal mask airway‐Supreme is a new second‐generation supraglottic airway that was recently released in limited pediatric sizes (sizes 1, 2). Methods: One hundred children, ASA I‐III, newborn to 16 years of age, and undergoing various procedures requiring a size 1, 2, or 3 laryngeal mask airway‐Supreme were studied. Assessments included insertion success rates, airway leak pressures, success of gastric tube insertion, quality of airway, and perioperative complications. Results: The first‐time insertion success rate was 97%, with an overall insertion success rate of 100%. The mean initial airway leak pressure for all patients was 22.3 ± 6.6 cm H2O. Gastric tube placement was possible in 98% of patients. Complications were noted in six patients: coughing or laryngospasm (n = 3), sore throat (n = 1), and dysphonia (n = 2). Conclusions: The laryngeal mask airway‐Supreme was inserted with a high degree of success on the first attempt by clinicians with limited prior experience with the device. It was effectively used for a variety of procedures in children undergoing spontaneous and mechanical ventilation with minimal complications. The leak pressures demonstrated in this study, along with access for gastric decompression, suggest that the laryngeal mask airway‐Supreme may be an effective device for positive pressure ventilation in children.  相似文献   
176.
In this paper, the finite‐horizon near optimal adaptive regulation of linear discrete‐time systems with unknown system dynamics is presented in a forward‐in‐time manner by using adaptive dynamic programming and Q‐learning. An adaptive estimator (AE) is introduced to relax the requirement of system dynamics, and it is tuned by using Q‐learning. The time‐varying solution to the Bellman equation in adaptive dynamic programming is handled by utilizing a time‐dependent basis function, while the terminal constraint is incorporated as part of the update law of the AE. The Kalman gain is obtained by using the AE parameters, while the control input is calculated by using AE and the system state vector. Next, to relax the need for state availability, an adaptive observer is proposed so that the linear quadratic regulator design uses the reconstructed states and outputs. For the time‐invariant linear discrete‐time systems, the closed‐loop dynamics becomes non‐autonomous and involved but verified by using standard Lyapunov and geometric sequence theory. Effectiveness of the proposed approach is verified by using simulation results. The proposed linear quadratic regulator design for the uncertain linear system requires an initial admissible control input and yields a forward‐in‐time and online solution without needing value and/or policy iterations. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
177.
178.
Malignant tumours of the sacrum may be primary or secondary. While sacral metastases are frequently encountered, a diagnostic dilemma can present when there is a single sacral bone tumour with no history or evidence of malignancy elsewhere in the body. Familiarity with the imaging features and clinical presentations of primary malignant bone tumours is helpful in narrowing the differential. This pictorial review will illustrate with both common and uncommon malignant sacral tumours CT, MRI and positron emission tomography/CT, highlighting the specific features of each.  相似文献   
179.
OBJECTIVE: The purpose of this review is to describe the imaging features, common and uncommon sites, metastatic pattern, and treatment response of synovial sarcoma. CONCLUSION: Synovial sarcoma primarily occurs in young adults, most commonly in the lower extremities; presents as a large, noninfiltrative, well-circumscribed mass adjacent to joints, often with punctuate calcifications; and may exhibit a triple signal pattern on T2-weighted images. Small synovial sarcomas can mimic benign lesions. This tumor has a propensity for late local recurrence and metastasis, most commonly to lung.  相似文献   
180.
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