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   307129篇
  免费   17502篇
  国内免费   8219篇
耳鼻咽喉   6153篇
儿科学   9288篇
妇产科学   4493篇
基础医学   19188篇
口腔科学   7531篇
临床医学   35365篇
内科学   48766篇
皮肤病学   3718篇
神经病学   14944篇
特种医学   13778篇
外国民族医学   42篇
外科学   61267篇
综合类   30715篇
现状与发展   31篇
一般理论   2篇
预防医学   18335篇
眼科学   8976篇
药学   27320篇
  263篇
中国医学   5459篇
肿瘤学   17216篇
  2024年   705篇
  2023年   4516篇
  2022年   11632篇
  2021年   14555篇
  2020年   9670篇
  2019年   14586篇
  2018年   9283篇
  2017年   8077篇
  2016年   10035篇
  2015年   12923篇
  2014年   24007篇
  2013年   21313篇
  2012年   23471篇
  2011年   20532篇
  2010年   18338篇
  2009年   17785篇
  2008年   16079篇
  2007年   16132篇
  2006年   13666篇
  2005年   9651篇
  2004年   5753篇
  2003年   4836篇
  2002年   3880篇
  2001年   3237篇
  2000年   2881篇
  1999年   2137篇
  1998年   2435篇
  1997年   2256篇
  1996年   1788篇
  1995年   1695篇
  1994年   1584篇
  1993年   1242篇
  1992年   1417篇
  1991年   1284篇
  1990年   1238篇
  1989年   1210篇
  1988年   1130篇
  1987年   1015篇
  1986年   830篇
  1985年   1755篇
  1984年   1890篇
  1983年   1359篇
  1982年   1451篇
  1981年   1423篇
  1980年   1217篇
  1979年   1026篇
  1978年   789篇
  1977年   784篇
  1976年   685篇
  1974年   457篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
《Clinical neurophysiology》2021,132(10):2357-2364
ObjectivesTo investigate the subcortical somatosensory evoked potentials (SEPs) to electrical stimulation of either muscle or cutaneous afferents.MethodsSEPs were recorded in 6 patients suffering from Parkinson’s disease (PD) who underwent electrode implantation in the pedunculopontine (PPTg) nucleus area. We compared SEPs recorded from the scalp and from the intracranial electrode contacts to electrical stimuli applied to: 1) median nerve at the wrist, 2) abductor pollicis brevis motor point, and 3) distal phalanx of the thumb. Also the high-frequency oscillations (HFOs) were analysed.ResultsAfter median nerve and pure cutaneous (distant phalanx of the thumb) stimulation, a P1-N1 complex was recorded by the intracranial lead, while the scalp electrodes recorded the short-latency far-field responses (P14 and N18). On the contrary, motor point stimulation did not evoke any low-frequency component in the PPTg traces, nor the N18 potential on the scalp. HFOs were recorded to stimulation of all modalities by the PPTg electrode contacts.ConclusionsStimulus processing within the cuneate nucleus depends on modality, since only the cutaneous input activates the complex intranuclear network possibly generating the scalp N18 potential.SignificanceOur results shed light on the subcortical processing of the somatosensory input of different modalities.  相似文献   
3.
ObjectiveNew-onset postoperative atrial fibrillation (POAF) after cardiac surgery is common, with rates up to 60%. POAF has been associated with early and late stroke, but its association with other cardiovascular outcomes is less known. The objective was to perform a meta-analysis of the studies reporting the association of POAF with perioperative and long-term outcomes in patients with cardiac surgery.MethodsWe performed a systematic review and a meta-analysis of studies that presented outcomes for cardiac surgery on the basis of the presence or absence of POAF. MEDLINE, EMBASE, and the Cochrane Library were assessed; 57 studies (246,340 patients) were selected. Perioperative mortality was the primary outcome. Inverse variance method and random model were performed. Leave-one-out analysis, subgroup analyses, and metaregression were conducted.ResultsPOAF was associated with perioperative mortality (odds ratio [OR], 1.92; 95% confidence interval [CI], 1.58-2.33), perioperative stroke (OR, 2.17; 95% CI, 1.90-2.49), perioperative myocardial infarction (OR, 1.28; 95% CI, 1.06-1.54), perioperative acute renal failure (OR, 2.74; 95% CI, 2.42-3.11), hospital (standardized mean difference, 0.80; 95% CI, 0.53-1.07) and intensive care unit stay (standardized mean difference, 0.55; 95% CI, 0.24-0.86), long-term mortality (incidence rate ratio [IRR], 1.54; 95% CI, 1.40-1.69), long-term stroke (IRR, 1.33; 95% CI, 1.21-1.46), and longstanding persistent atrial fibrillation (IRR, 4.73; 95% CI, 3.36-6.66).ConclusionsThe results suggest that POAF after cardiac surgery is associated with an increased occurrence of most short- and long-term cardiovascular adverse events. However, the causality of this association remains to be established.  相似文献   
4.
5.
目的对治疗前原发性骶尾部脊索瘤(PSC)CT图像分型,并分析其CT征象,为诊断和个性化治疗提供依据。方法回顾性分析101例PSC患者治疗前的CT图像,包括肿瘤的部位、范围、大小、密度、肿瘤与邻近结构的关系。按照肿瘤的部位由上及下分为Ⅰ~Ⅳ型,并根据肿瘤侵犯的范围从小到大分为a^d亚型。采用Kruskal-Wallis H检验比较PSC各亚型的占比,并对各亚型之间进行两两比较。采用R×C列联表精确概率检验比较分型和亚型肿瘤钙化的发生率。采用单因素方差分析及LSD-t检验对各分型和亚型肿瘤的大小和密度进行分析、比较。结果101例PSC中,Ⅰ~Ⅳ型的发生率分别为17.8%、30.7%、36.6%、14.9%,a^d亚型的占比分别为9.9%、25.7%、58.4%、5.9%。各亚型的占比差异具有统计学意义(P=0.012)。c亚型明显高于a亚型(P=0.039),d亚型明显低于a亚型(P=0.036),其余各型之间无明显差异。各分型肿瘤内钙化的差异无统计学意义(P=0.233);各亚型肿瘤内钙化的差异有统计学意义(P=0.003),a^d亚型肿瘤钙化的比率逐渐增加。Ⅰ型肿瘤的左右径及上下径明显大于Ⅱ~Ⅳ型(P<0.05)。a亚型与b亚型肿瘤之间前后径的差异无统计学意义(P=0.102),b^d亚型之间前后径的差异均有统计学意义(P<0.05);不同亚型肿瘤之间的左右径、上下径之间的差异均有统计学意义(P<0.05),a亚型径线最小,d亚型径线最大。结论101例PSC中,Ⅱ、Ⅲ型最多见,肿瘤较少累及第一骶骨;各亚型中,a型较少见,c亚型最多见,d亚型最少见。肿瘤的密度与分型无关,肿瘤内钙化与亚型有关。Ⅰ型肿瘤侵犯的范围较Ⅱ~Ⅳ型广泛,a^d亚型肿瘤的径线逐渐增大,CT分型有利于判断肿瘤的范围。PSC诊断延迟现象比较明显,但很少发生远处侵犯和转移。CT图像可对治疗前PSC分型,为诊断和个性化治疗提供依据。  相似文献   
6.

Background

Purulent bacterial pericarditis is a rare and potentially fatal disease. The course may be fulminant, and the presentation may pose a diagnostic challenge.

Case report

An otherwise healthy 75-year-old male was brought to the emergency department in a state of general deterioration, confusion, and shock. Bedside ultrasound showed a significant pericardial effusion. His condition quickly deteriorated and the resuscitation included emergent bedside pericardiocentesis. The drainage was purulent and later cultures grew out Streptococcus pneumoniae.

Why should an emergency physician be aware of this?

Purulent pericarditis is extremely rare but should be considered in the patient with a fulminant infectious process (particularly pneumonia) and signs of pericardial effusion. Treatment should include appropriate antibiotics and early drainage.  相似文献   
7.
We report two British cases of liver abscess, due to Klebsiella pneumoniae and associated with synchronous infection elsewhere, which required liver resection for definitive treatment. They illustrate the geographic spread of aggressive K pneumoniae liver infection and demonstrate the importance of early aggressive treatment.  相似文献   
8.
Abstract

Supporting patients in making informed healthcare decisions is a cornerstone of ethical medical practice. Surgeons frequently draw for and show images to patients when consenting them for operations but the value of this practice in informed decision-making is unclear. An audit was conducted in a General Surgery Department. 244 patients completed questionnaires on the value of visual materials when giving consent for surgery. The complexity of the operations was classified into “simple”, “moderate” or “complex”. 100% of patients felt they had given informed consent to surgery. 62% of patients received at least one form of visual material during the consenting process. All patients who received a drawing, and 99% of those provided with other images, valued these resources. Visual materials were considered more useful to patients when giving consent for moderate or complex operations than simple ones. Approximately one third of patients who did not receive visual materials would have appreciated these when making an informed decision. This research highlights the value of surgeons drawing for, and providing other visual resources to, their patients as part of the consent process. There is a role for further research and training materials in drawing skills for surgeons.  相似文献   
9.
10.
Central illustration: cumulative major adverse cardiac events (MACE) and bioresorbable vascular scaffold (BVS) thrombosis rates after 1, 2, 3, 4 and 5 years.
  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