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   1719378篇
  免费   126034篇
  国内免费   3833篇
耳鼻咽喉   22029篇
儿科学   56512篇
妇产科学   46721篇
基础医学   244453篇
口腔科学   49344篇
临床医学   153673篇
内科学   338007篇
皮肤病学   39268篇
神经病学   133981篇
特种医学   64639篇
外国民族医学   249篇
外科学   260442篇
综合类   39349篇
现状与发展   4篇
一般理论   569篇
预防医学   126584篇
眼科学   40758篇
药学   125136篇
  7篇
中国医学   4495篇
肿瘤学   103025篇
  2021年   13026篇
  2019年   13816篇
  2018年   20307篇
  2017年   15521篇
  2016年   16956篇
  2015年   19358篇
  2014年   26737篇
  2013年   38957篇
  2012年   53918篇
  2011年   56734篇
  2010年   33546篇
  2009年   31400篇
  2008年   52822篇
  2007年   56137篇
  2006年   56592篇
  2005年   53831篇
  2004年   51988篇
  2003年   49324篇
  2002年   47537篇
  2001年   92189篇
  2000年   93977篇
  1999年   77351篇
  1998年   20023篇
  1997年   17533篇
  1996年   17609篇
  1995年   16974篇
  1994年   15519篇
  1993年   14307篇
  1992年   57723篇
  1991年   55604篇
  1990年   53288篇
  1989年   51054篇
  1988年   46394篇
  1987年   45178篇
  1986年   42512篇
  1985年   40235篇
  1984年   29620篇
  1983年   25167篇
  1982年   14169篇
  1981年   12656篇
  1979年   25768篇
  1978年   17742篇
  1977年   15066篇
  1976年   14036篇
  1975年   14730篇
  1974年   17807篇
  1973年   17132篇
  1972年   15857篇
  1971年   14601篇
  1970年   13573篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.

Purpose

The purpose of this study was to assess the potential of a deep learning model to discriminate between benign and malignant breast lesions using magnetic resonance imaging (MRI) and characterize different histological subtypes of breast lesions.

Materials and methods

We developed a deep learning model that simultaneously learns to detect lesions and characterize them. We created a lesion-characterization model based on a single two-dimensional T1-weighted fat suppressed MR image obtained after intravenous administration of a gadolinium chelate selected by radiologists. The data included 335 MR images from 335 patients, representing 17 different histological subtypes of breast lesions grouped into four categories (mammary gland, benign lesions, invasive ductal carcinoma and other malignant lesions). Algorithm performance was evaluated on an independent test set of 168 MR images using weighted sums of the area under the curve (AUC) scores.

Results

We obtained a cross-validation score of 0.817 weighted average receiver operating characteristic (ROC)-AUC on the training set computed as the mean of three-shuffle three-fold cross-validation. Our model reached a weighted mean AUC of 0.816 on the independent challenge test set.

Conclusion

This study shows good performance of a supervised-attention model with deep learning for breast MRI. This method should be validated on a larger and independent cohort.  相似文献   
72.
Aim: The aim of study was to investigate the opportunities of local phlebectomy in the elimination of isolated pelvic-perineal reflux (PPR), as well as to determine the feasibility of endovascular embolization of the tributaries of internal iliac veins in PPR. Clinical trial no. NCT01598051.

Materials and methods: The work is based on the results of examination and treatment of 43 female patients with varicose veins of the pelvis, perineum, and lower extremities. Patients had no signs of pelvic congestion syndrome (PCS). All patients underwent duplex ultrasound scanning (DUS) and ovariography with pelvic phlebography (OPP). For the elimination of PPR, local phlebectomy was performed in the major labia and perineal area, with maximal possible mobilization of the vessel within the operative wound (33 patients). In 10 patients with isolated varicose transformation of the superficial veins on the posterior thigh, mini-phlebectomy was performed using the Varady phlebectomy extractors.

Results and discussion: The varicose syndrome of the external genitalia, perineum, and posterior thigh was successfully treated in 100% of patients. Findings suggest that thorough mobilization and excision of the veins of the pudendal labia, perineum, and subcutaneous veins of the thigh is a reliable method for eliminating the pathological reflux from the intrapelvic veins to the superficial veins of the perineum and lower extremities. No recurrences of vulvar, perineal varices or dilation of the veins of the lower extremities were observed in 100% of patients over the 3-year follow-up period.

Conclusion: Local phlebectomy is an effective technique for eliminating the isolated PPR in patients with varicose transformation of intrapelvic, vulvar, or perineal veins. Endovascular embolization of the tributaries of the internal iliac veins is not an essential component in the treatment of PPR. The present study has a limitation due to the absence of patients with PCS. The effectiveness of phlebectomy in the treatment of isolated PPR was studied.  相似文献   

73.

Aims

Delaying progression, ameliorating symptoms and maintaining quality of life (QoL) are primary aims of treatment for metastatic castrate-resistant prostate cancer (mCRPC). Real-world rather than clinical trial data about symptoms and side-effects are sparse. In EXTREQOL, patients' QoL, pain and information needs were recorded during treatment.

Material and methods

Men with mCRPC from 20 UK cancer centres starting various systemic mCRPC treatments completed QoL, pain and information needs questionnaires at baseline, 3 and 6 months.

Results

In total, 132 patients were recruited. Overall QoL declined significantly by 6 months (Functional Assessment of Cancer Therapy-Prostate [FACT-P] mean = –3.89, 95% confidence interval –6.7 to –1.05, P = 0.007; Trial Outcome Index [TOI] analysis mean = –3.10, 95% confidence interval –5.34 to –0.83, P = 0.007). Those who came off novel therapy and remained on luteinising hormone-releasing hormone agonist therapy alone had worse scores than patients receiving concomitant chemotherapy (Prostate Concerns Subscale mean difference = –4.45, 95% confidence interval –7.06 to –1.83, P = 0.001; TOI mean difference = –5.62, 95% confidence interval –10.97 to –0.26, P = 0.040). At 3 and 6 months, men who reported pain at baseline improved (43%, 40%), but for others pain levels remained the same (45%, 42%) or worsened (13%, 18%). Information regarding supportive care was lacking throughout the period of time on the study.

Conclusion

Most mCRPC treated patients experience reduced QoL and inadequate pain control. More help with pain management and better information provision regarding supportive care is warranted.  相似文献   
74.
ABSTRACT

Introduction

Alcohol withdrawal syndrome is a common and life-threatening condition in patients suffering from alcohol use disorder. Treatment of this syndrome is challenging, especially in patients that are critically ill, either because of withdrawal symptoms or underlying conditions. For the treatment, several pharmacological agents exist, such as benzodiazepines, barbiturates, or dexmedetomidine. Nonetheless, as alcohol withdrawal syndromes can occur in every clinical setting, it is necessary to provide a guideline for clinicians confronted with this syndrome in varying clinical contexts.  相似文献   
75.
76.
77.
78.
79.
80.
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