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   11142篇
  免费   1465篇
  国内免费   327篇
耳鼻咽喉   106篇
儿科学   132篇
妇产科学   85篇
基础医学   1899篇
口腔科学   223篇
临床医学   1249篇
内科学   1726篇
皮肤病学   86篇
神经病学   270篇
特种医学   404篇
外国民族医学   4篇
外科学   1593篇
综合类   1630篇
现状与发展   2篇
一般理论   3篇
预防医学   408篇
眼科学   124篇
药学   641篇
  12篇
中国医学   1180篇
肿瘤学   1157篇
  2024年   8篇
  2023年   142篇
  2022年   251篇
  2021年   562篇
  2020年   546篇
  2019年   471篇
  2018年   467篇
  2017年   487篇
  2016年   566篇
  2015年   576篇
  2014年   935篇
  2013年   887篇
  2012年   824篇
  2011年   797篇
  2010年   676篇
  2009年   606篇
  2008年   590篇
  2007年   535篇
  2006年   451篇
  2005年   383篇
  2004年   341篇
  2003年   279篇
  2002年   288篇
  2001年   215篇
  2000年   144篇
  1999年   132篇
  1998年   124篇
  1997年   96篇
  1996年   67篇
  1995年   64篇
  1994年   61篇
  1993年   43篇
  1992年   45篇
  1991年   40篇
  1990年   29篇
  1989年   33篇
  1988年   35篇
  1987年   22篇
  1986年   30篇
  1985年   30篇
  1984年   7篇
  1983年   11篇
  1982年   5篇
  1981年   13篇
  1980年   2篇
  1979年   2篇
  1978年   4篇
  1976年   5篇
  1974年   2篇
  1970年   1篇
排序方式: 共有10000条查询结果,搜索用时 343 毫秒
1.
Anaplastic thyroid carcinoma (ATC) is an aggressive thyroid malignancy with high mortality rate. This malignancy arises in thyroid follicular cells either denovo or with an associated differentiated thyroid carcinoma component. Clinically, it usually presents as a rapidly enlarging mass, pain and locally compressive symptoms. Histopathologic variability and heterogeneity often pose diagnostic challenges, especially in scant and paucicellular specimens. This article describes the clinical, histopathologic and molecular features of ATC and also addresses the associated diagnostic limitations and challenges.  相似文献   
2.
3.
Breast pseudoaneurysms after a core needle biopsy are a rare complication with a low incidence. However, it is important to be aware of the possibility of complications that require treatment.  相似文献   
4.
The identification of EGFR mutations in non‐small‐cell lung cancer is important for selecting patients, who may benefit from treatment with EGFR tyrosine kinase inhibitors. The analysis is usually performed on cytological aspirates and/or histological needle biopsies, representing a small fraction of the tumour volume. The aim of the present investigation was to evaluate the diagnostic performance of this molecular test. We retrospectively included 201 patients with primary adenocarcinoma of the lung. EGFR mutation status (exon 19 deletions and exon 21 L858R point mutation) was evaluated on both pre‐operative biopsies (131 histological and 70 cytological) and on the surgical specimens, using PCR. Samples with low tumour cell fraction were assigned to laser micro‐dissection (LMD). We found nine (4.5%) patients with EGFR mutation in the lung tumour resections, but failed to identify mutation in one of the corresponding pre‐operative, cytological specimens. Several (18.4%) analyses of the pre‐operative biopsies were inconclusive, especially in case of biopsies undergoing LMD and regarding exon 21 analysis. Discrepancy of mutation status in one patient may reflect intra‐tumoural heterogeneity or technical issues. Moreover, several inconclusive results in the diagnostic biopsies reveal that attention must be paid on the suitability of pre‐operative biopsies for EGFR mutation analysis.  相似文献   
5.
目的:分析超声内镜引导下经支气管针吸活检(endobronchial ultrasound-guided transbronchial needle aspiration,EBUS-TBNA)术中肿大纵隔淋巴结的超声图像特点,探讨EBUS-TBNA超声内镜对纵隔淋巴结良恶性的鉴别诊断价值,以期提高EBUS-TBNA对纵隔淋巴结恶性病变的活检率。方法:回顾性分析2014年10月至2018年11月行EBUS-TBNA患者的超声内镜图像。我们使用以下EBUS超声内镜特征来预测淋巴结的良恶:回声,长轴长度,短轴长度,纵横比,形态,边界,淋巴门有无,淋巴结内血流信号分级。将超声检查结果与最终病理结果或临床随访结果进行比较。采用SPSS 20.0软件进行统计学分析,采用logistic回归分析评价肿大淋巴结EBUS-TBNA超声内镜下的特征与良恶性的相关性,以 P<0.05 为标准判定差异有统计学意义。结果:对130例纵隔淋巴结肿大患者的227个淋巴结进行回顾性分析,67.4%的肿大淋巴结被证实为恶性转移。Logistic回归分析显示回声、长轴及短轴的长度、正常淋巴门结构的消失是诊断恶性淋巴结的独立预测因素。结论:纵隔恶性淋巴结具有一定的超声特征,可以通过这些超声特征提高EBUS-TBNA对纵隔恶性淋巴结的检出率。  相似文献   
6.
Preeclampsia is a disease with a significant incidence worldwide that is directly associated with 15% of maternal deaths. This is usually characterized by the presence of hypertension and proteinuria, which manifests itself from the middle of pregnancy. MicroRNAs are single-stranded RNA molecules that act primarily by degrading transcribed messenger RNA or inhibiting microRNA translation. Placental microRNAs play a role in the growth and function of the placenta, their potential use as diagnostic biomarkers is considered feasible due to the ability to enter the maternal circulation and be detectable in maternal plasma.  相似文献   
7.
8.
9.
Abstract

Objective

Two similarly designed studies compared user experiences with a second-generation extra-thin-wall, 5-bevel 32?G?×?4?mm pen needle (PN) with redesigned hub versus four thinner commercially available PNs.  相似文献   
10.
Despite a population of nearly 60 million, there is currently not a single interventional radiologist in Tanzania. Based on an Interventional Radiology (IR) Readiness Assessment, the key obstacles to establishing IR in Tanzania are the lack of training opportunities and limited availability of disposable equipment. An IR training program was designed and initiated, which relies on US-based volunteer teams of IR physicians, nurses, and technologists to locally train radiology residents, nurses, and technologists. Preliminary results support this strategy for addressing the lack of training opportunities and provide a model for introducing IR to other resource-limited settings.  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