全文获取类型
收费全文 | 34197篇 |
免费 | 2248篇 |
国内免费 | 99篇 |
专业分类
耳鼻咽喉 | 495篇 |
儿科学 | 836篇 |
妇产科学 | 476篇 |
基础医学 | 4125篇 |
口腔科学 | 453篇 |
临床医学 | 3724篇 |
内科学 | 7016篇 |
皮肤病学 | 426篇 |
神经病学 | 2999篇 |
特种医学 | 1361篇 |
外科学 | 5701篇 |
综合类 | 391篇 |
一般理论 | 40篇 |
预防医学 | 3075篇 |
眼科学 | 520篇 |
药学 | 2557篇 |
中国医学 | 30篇 |
肿瘤学 | 2319篇 |
出版年
2024年 | 27篇 |
2023年 | 249篇 |
2022年 | 475篇 |
2021年 | 1087篇 |
2020年 | 636篇 |
2019年 | 976篇 |
2018年 | 1173篇 |
2017年 | 813篇 |
2016年 | 824篇 |
2015年 | 983篇 |
2014年 | 1477篇 |
2013年 | 1942篇 |
2012年 | 2799篇 |
2011年 | 2867篇 |
2010年 | 1502篇 |
2009年 | 1392篇 |
2008年 | 2395篇 |
2007年 | 2337篇 |
2006年 | 2149篇 |
2005年 | 2175篇 |
2004年 | 2046篇 |
2003年 | 1829篇 |
2002年 | 1682篇 |
2001年 | 185篇 |
2000年 | 166篇 |
1999年 | 219篇 |
1998年 | 312篇 |
1997年 | 239篇 |
1996年 | 236篇 |
1995年 | 163篇 |
1994年 | 166篇 |
1993年 | 139篇 |
1992年 | 86篇 |
1991年 | 77篇 |
1990年 | 67篇 |
1989年 | 65篇 |
1988年 | 60篇 |
1987年 | 44篇 |
1986年 | 34篇 |
1985年 | 39篇 |
1984年 | 54篇 |
1983年 | 57篇 |
1982年 | 69篇 |
1981年 | 45篇 |
1980年 | 33篇 |
1979年 | 21篇 |
1978年 | 21篇 |
1977年 | 18篇 |
1976年 | 12篇 |
1975年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Kevin Kyung Ho Choi Santosh Sanagapalli 《World journal of gastrointestinal oncology》2022,14(3):568-586
Barrett's esophagus (BE) is the precursor to esophageal adenocarcinoma (EAC). Progression to cancer typically occurs in a stepwise fashion through worsening dysplasia and ultimately, invasive neoplasia. Established EAC with deep involvement of the esophageal wall and/or metastatic disease is invariably associated with poor long-term survival rates. This guides the rationale of surveillance of Barrett’s in an attempt to treat lesions at an earlier, and potentially curative stage. The last two decades have seen a paradigm shift in management of Barrett’s with rapid expansion in the role of endoscopic eradication therapy (EET) for management of dysplastic and early neoplastic BE, and there have been substantial changes to international consensus guidelines for management of early BE based on evolving evidence. This review aims to assist the physician in the therapeutic decision-making process with patients by comprehensive review and summary of literature surrounding natural history of Barrett’s by histological stage, and the effectiveness of interventions in attenuating the risk posed by its natural history. Key findings were as follows. Non-dysplastic Barrett’s is associated with extremely low risk of progression, and interventions cannot be justified. The annual risk of cancer progression in low grade dysplasia is between 1%-3%; EET can be offered though evidence for its benefit remains confined to highly select settings. High-grade dysplasia progresses to cancer in 5%-10% per year; EET is similarly effective to and less morbid than surgery and should be routinely performed for this indication. Risk of nodal metastases in intramucosal cancer is 2%-4%, which is comparable to operative mortality rate, so EET is usually preferred. Submucosal cancer is associated with nodal metastases in 14%-41% hence surgery remains standard of care, except for select situations. 相似文献
2.
3.
Phoebe Hammer Kevin White Stephanie Mengden Vessy Korcheva Philipp W. Raess 《Journal of cutaneous pathology》2019,46(5):343-346
Cutaneous leiomyomas are rare benign smooth‐muscle tumors. These lesions are distinguished based on their cell of origin and are subclassified as pilar leiomyoma, angioleiomyoma, and genital‐type leiomyoma. Nipple leiomyoma is the least common genital‐type leiomyoma, arising from the dartoic muscle cell of the nipple. Histologic examination of the lesion is necessary for definitive diagnosis, and these uncommon tumors can pose a diagnostic challenge. We describe herein a series of six nipple leiomyomas with a spectrum of histologic appearances. 相似文献
4.
5.
Distribution of temperature changes and neurovascular coupling in rat brain following 3,4‐methylenedioxymethamphetamine (MDMA, “ecstasy”) exposure
下载免费PDF全文
![点击此处可从《NMR in biomedicine》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Daniel Coman Basavaraju G. Sanganahalli Lihong Jiang Fahmeed Hyder Kevin L. Behar 《NMR in biomedicine》2015,28(10):1257-1266
(+/?)3,4‐methylenedioxymethamphetamine (MDMA, “ecstasy”) is an abused psychostimulant that produces strong monoaminergic stimulation and whole‐body hyperthermia. MDMA‐induced thermogenesis involves activation of uncoupling proteins (UCPs), primarily a type specific to skeletal muscle (UCP‐3) and absent from the brain, although other UCP types are expressed in the brain (e.g. thalamus) and might contribute to thermogenesis. Since neuroimaging of brain temperature could provide insights into MDMA action, we measured spatial distributions of systemically administered MDMA‐induced temperature changes and dynamics in rat cortex and subcortex using a novel magnetic resonance method, Biosensor Imaging of Redundant Deviation in Shifts (BIRDS), with an exogenous temperature‐sensitive probe (thulium ion and macrocyclic chelate 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetramethyl‐1,4,7,10‐tetraacetate (DOTMA4?)). The MDMA‐induced temperature rise was greater in the cortex than in the subcortex (1.6 ± 0.4 °C versus 1.3 ± 0.4 °C) and occurred more rapidly (2.0 ± 0.2 °C/h versus 1.5 ± 0.2 °C/h). MDMA‐induced temperature changes and dynamics in the cortex and body were correlated, although the body temperature exceeded the cortex temperature before and after MDMA. Temperature, neuronal activity, and blood flow (CBF) were measured simultaneously in the cortex and subcortex (i.e. thalamus) to investigate possible differences of MDMA‐induced warming across brain regions. MDMA‐induced warming correlated with increases in neuronal activity and blood flow in the cortex, suggesting that the normal neurovascular response to increased neural activity was maintained. In contrast to the cortex, a biphasic relationship was seen in the subcortex (i.e. thalamus), with a decline in CBF as temperature and neural activity rose, transitioning to a rise in CBF for temperature above 37 °C, suggesting that MDMA affected CBF and neurovascular coupling differently in subcortical regions. Considering that MDMA effects on CBF and heat dissipation (as well as potential heat generation) may vary regionally, neuroprotection may require different cooling strategies. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
6.
7.
8.
9.
10.