收费全文 | 1697672篇 |
免费 | 124272篇 |
国内免费 | 3793篇 |
耳鼻咽喉 | 21763篇 |
儿科学 | 55735篇 |
妇产科学 | 46187篇 |
基础医学 | 241546篇 |
口腔科学 | 48774篇 |
临床医学 | 151616篇 |
内科学 | 334161篇 |
皮肤病学 | 38681篇 |
神经病学 | 131373篇 |
特种医学 | 63962篇 |
外国民族医学 | 242篇 |
外科学 | 257588篇 |
综合类 | 39037篇 |
现状与发展 | 4篇 |
一般理论 | 531篇 |
预防医学 | 124461篇 |
眼科学 | 40231篇 |
药学 | 123893篇 |
7篇 | |
中国医学 | 4481篇 |
肿瘤学 | 101464篇 |
2021年 | 12846篇 |
2019年 | 13582篇 |
2018年 | 20002篇 |
2017年 | 15257篇 |
2016年 | 16661篇 |
2015年 | 19011篇 |
2014年 | 26278篇 |
2013年 | 38059篇 |
2012年 | 52877篇 |
2011年 | 55558篇 |
2010年 | 32857篇 |
2009年 | 30769篇 |
2008年 | 51641篇 |
2007年 | 54942篇 |
2006年 | 55372篇 |
2005年 | 52667篇 |
2004年 | 50872篇 |
2003年 | 48271篇 |
2002年 | 46465篇 |
2001年 | 91837篇 |
2000年 | 93657篇 |
1999年 | 77007篇 |
1998年 | 19742篇 |
1997年 | 17285篇 |
1996年 | 17414篇 |
1995年 | 16763篇 |
1994年 | 15307篇 |
1993年 | 14087篇 |
1992年 | 57409篇 |
1991年 | 55290篇 |
1990年 | 53010篇 |
1989年 | 50777篇 |
1988年 | 46165篇 |
1987年 | 44963篇 |
1986年 | 42245篇 |
1985年 | 40010篇 |
1984年 | 29362篇 |
1983年 | 24923篇 |
1982年 | 13915篇 |
1979年 | 25561篇 |
1978年 | 17594篇 |
1977年 | 14924篇 |
1976年 | 13888篇 |
1975年 | 14579篇 |
1974年 | 17648篇 |
1973年 | 16968篇 |
1972年 | 15695篇 |
1971年 | 14474篇 |
1970年 | 13443篇 |
1969年 | 12526篇 |
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