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   6120篇
  免费   403篇
  国内免费   37篇
耳鼻咽喉   63篇
儿科学   93篇
妇产科学   150篇
基础医学   794篇
口腔科学   61篇
临床医学   679篇
内科学   1453篇
皮肤病学   76篇
神经病学   534篇
特种医学   230篇
外科学   998篇
综合类   39篇
预防医学   332篇
眼科学   113篇
药学   387篇
中国医学   5篇
肿瘤学   553篇
  2024年   10篇
  2023年   61篇
  2022年   103篇
  2021年   235篇
  2020年   162篇
  2019年   219篇
  2018年   262篇
  2017年   170篇
  2016年   181篇
  2015年   160篇
  2014年   251篇
  2013年   327篇
  2012年   490篇
  2011年   405篇
  2010年   248篇
  2009年   236篇
  2008年   365篇
  2007年   368篇
  2006年   364篇
  2005年   339篇
  2004年   283篇
  2003年   261篇
  2002年   259篇
  2001年   80篇
  2000年   64篇
  1999年   57篇
  1998年   59篇
  1997年   49篇
  1996年   48篇
  1995年   41篇
  1994年   27篇
  1993年   15篇
  1992年   29篇
  1991年   30篇
  1990年   28篇
  1989年   29篇
  1988年   24篇
  1987年   21篇
  1986年   21篇
  1985年   17篇
  1984年   11篇
  1983年   9篇
  1982年   7篇
  1981年   10篇
  1976年   10篇
  1974年   7篇
  1973年   7篇
  1972年   12篇
  1970年   11篇
  1969年   9篇
排序方式: 共有6560条查询结果,搜索用时 15 毫秒
991.
992.
993.

Introduction

MNNG HOS transforming gene (MET) abnormalities such as amplification and exon 14 mutations may be responsive to targeted therapies. They are prevalent in lung sarcomatoid carcinomas (LSCs) and must be diagnosed as efficiently as possible. Hypothetically, c-MET overexpression by immunohistochemistry (IHC) may prove effective as a screening test for MET abnormalities.

Methods

Tissue samples were obtained from consecutive patients with a resected LSC in four oncologic centers. IHC was performed using the SP44 antibody (Ventana, Tucson, Arizona) and evaluated using the MetMab score and H-score. Fluorescence in situ hybridization was applied with the dual color probe set from Zytovision (Clinisciences, Nanterre, France). True MET amplification was diagnosed when MET gene copy number was 5 or greater and the ratio between MET gene copy number and chromosome 7 number was greater than 2. All MET exon 14 alterations including those affecting splice sites occurring within splice donor and acceptor sites were detected in the routine molecular testing on genetic platforms.

Results

A total of 81 LSCs were included. Fourteen (17%) exhibited positive IHC using the MetMab score and 15 (18.5%) using the H-score. MET amplification was detected in six tumors (8.5%) and MET exon 14 mutation in five (6%). A weak positive correlation between IHC and fluorescence in situ hybridization was found (r = 0.27, p = 0.0001). IHC sensitivity for MET amplification was 50%, with a specificity of 83%, positive predictive value of 21.4%, and negative predictive value of 94.7%. IHC sensitivity for MET exon 14 mutations was 20%, with a specificity of 83%, positive predictive value of 7%, and negative predictive value of 94%.

Conclusion

IHC is not a relevant screening tool for MET abnormalities in LSC.  相似文献   
994.

Background

Several agents have demonstrated an overall survival (OS) benefit in patients with metastatic castration-resistant prostate cancer (mCRPC); however, the optimal sequencing of these therapies is unknown as a result of a lack of prospective randomized controlled trials. This retrospective study aimed to identify clinical factors influencing outcomes and to determine optimal treatment sequencing in patients with mCRPC treated with cabazitaxel (CABA) and/or androgen receptor–targeted agents (ART) after androgen-deprivation therapy (ADT) and docetaxel (DOC).

Patients and Methods

Records of 574 consecutive patients treated (2012?2016) at 44 centers in 6 countries were retrospectively examined.

Results

A total of 267 patients received ADT → DOC → CABA (group 1), 183 patients ADT → DOC → ART → CABA (group 2), and 124 patients ADT → DOC → CABA → ART (group 3), with respective median OS from diagnosis of mCRPC of 38.3, 44.45, and 53.9 months (P = .012 for group 3 vs. group 1). Multivariate analysis showed response to first ADT ≤ 12 months, Gleason score of 8 to 10, clinical progression, and high prostate-specific antigen levels at mCRPC diagnosis were associated with worse OS. Prior receipt of ART did not influence activity of CABA.

Conclusion

OS appeared to increase with the number of life-extending therapies, with a sequence including DOC, CABA, and an ART providing the greatest OS benefit.  相似文献   
995.

Background and Objectives

Evaluation of mandibular reconstructions with free fibula flaps. Identification of factors associated with major recipient site complications, that is, necessitating surgical intervention under general anaesthesia.

Methods

Seventy‐nine reconstructions were included. The following factors were analyzed: fixation type, number of osteotomies, site of defect (bilateral/unilateral), surgeon, sex, ASA classification, continuous smoking, pathological N‐stage, age, defect size, flap ischemic time, and postoperative radiotherapy. Proportional hazards regression was used to test the effect on the time between reconstruction and intervention.

Results

Sixty‐nine (87%) of the 79 fibula flaps were successful at the last follow‐up. Forty‐eight major recipient site complications occurred in 41 reconstructions. Nineteen complications required surgical intervention within six weeks and were mostly vascular problems, necessitating immediate intervention. These early complications were associated with defects crossing the midline, with an estimated relative risk of 5.3 (CI 1.1‐20, P = 0.01). Twenty‐nine complications required surgical intervention more than 6 weeks after the reconstruction. These late complications generally occurred after months or years, and were associated with smoking, with an estimated relative risk of 2.8 (CI 1.0‐8.3, P = 0.05).

Conclusions

Fibula flaps crossing the midline have a higher risk of early major recipient site complications than unilateral reconstructions. Smoking increases the risk of late complications.  相似文献   
996.

Purpose

Plasmablastic lymphoma (PBL) is a rare variant of diffuse large B cell lymphomas (DLBCL) clinically characterized by a poorer prognostic. Few clinical and imaging data are available and derived from pooled case reports and small series. The aim of the study was to evaluate the FDG avidity at baseline and the utility of 18-Fluorodeoxyglucose (FDG) positron-emission-tomography/computed-tomography (PET/CT) for staging and response assessment.

Methods

Patients with newly diagnosed PBL seen at Lymphoma Study Association centers during the period 2005–2015 were included if they underwent a PET/CT at staging and at the end of treatment (eotPET) and had received an anthracycline-based first line therapy. EotPET scans were analyzed using the 5-point-scale visual analysis in accordance with Lugano criteria. Patients were classified in complete metabolic response (CMR) or no-CMR including partial metabolic response (PMR), stable disease (SD) and progression disease (PD). EotPET results were assessed for the ability to predict event free survival (EFS) and overall survival (OS).

Results

Thirty-five PBL patients fulfilled the inclusion criteria. The median follow-up was 34 months (2.8–120 months). FDG avidity was found in all patients at diagnosis. Most patients (80%) achieved CMR, and 20% were no-CMR including 9% PMR, 6% SD, and 6% PD. A CMR after first line chemotherapy predicted higher EFS (p?<?0.0001) and OS (p?=?0.0006).

Conclusions

This study confirmed the FDG avidity of PBL subtype and the usefulness of PET/CT scanning in restaging an aggressive lymphoma at the completion of chemotherapy. EotPET can predict outcomes following treatment in patients with PBL.
  相似文献   
997.

Purpose

By increasing lung volume and decreasing respiration-induced tumour motion amplitude, administration of continuous positive airway pressure (CPAP) during stereotactic ablative radiotherapy (SABR) could allow for better sparing of the lungs and heart. In this study, we evaluated the effect of CPAP on lung volume, tumour motion amplitude and baseline shift, as well as the dosimetric impact of the strategy.

Methods

Twenty patients with lung tumours referred for SABR underwent 4D-computed tomography (CT) scans with and without CPAP (CPAP/noCPAP) at two timepoints (T0/T1). First, CPAP and noCPAP scans were compared for lung volume, tumour motion amplitude, and baseline shift. Next, CPAP and noCPAP treatment plans were computed and compared for lung dose parameters (mean lung dose (MLD), lung volume receiving 20 Gy (V20Gy), 13 Gy (V13Gy), and 5 Gy (V5Gy)) and mean heart dose (MHD).

Results

On average, CPAP increased lung volume by 8.0% (p?<?0.001) and 6.3% (p?<?0.001) at T0 and T1, respectively, but did not change tumour motion amplitude or baseline shift. As a result, CPAP administration led to an absolute decrease in MLD, lung V20Gy, V13Gy and V5Gy of 0.1?Gy (p?=?0.1), 0.4% (p?=?0.03), 0.5% (p?=?0.04) and 0.5% (p?=?0.2), respectively, while having no significant influence on MHD.

Conclusions

In patients referred for SABR for lung tumours, CPAP increased lung volume without modifying tumour motion or baseline shift. As a result, CPAP allowed for a slight decrease in radiation dose to the lungs, which is unlikely to be clinically significant.
  相似文献   
998.
999.

Purpose

Resolution of reflux in meningomyelocele patients is a reflection of improved bladder storage. We correlated resolution of reflux with changes observed in sequential urodynamic studies.

Materials and Methods

The study included 27 children with meningomyelocele born between 1975 and 1985 who presented with or developed vesicoureteral reflux. Resolution of reflux was observed during the 10-year followup period as they were treated with a regimen of clean intermittent catheterization and pharmaco-therapy. Urodynamic studies were performed when vesicoureteral reflux was present and subsequent to its resolution. The urodynamic parameters compared in the 2 studies included bladder capacity, pressure specific bladder volume, bladder compliance and leak point pressure.

Results

Significant increases in bladder capacity, pressure specific bladder volume and bladder compliance were noted. Leak point pressure appeared to be decreased subsequent to resolution of reflux.

Conclusions

Resolution of reflux in meningomyelocele patients correlates with changes in parameters of bladder storage observed on sequential urodynamic studies.  相似文献   
1000.
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