全文获取类型
收费全文 | 1245869篇 |
免费 | 79916篇 |
国内免费 | 2927篇 |
专业分类
耳鼻咽喉 | 15068篇 |
儿科学 | 43020篇 |
妇产科学 | 33322篇 |
基础医学 | 172128篇 |
口腔科学 | 30851篇 |
临床医学 | 108467篇 |
内科学 | 242943篇 |
皮肤病学 | 25314篇 |
神经病学 | 101961篇 |
特种医学 | 49560篇 |
外国民族医学 | 333篇 |
外科学 | 186852篇 |
综合类 | 26378篇 |
一般理论 | 408篇 |
预防医学 | 102185篇 |
眼科学 | 26658篇 |
药学 | 86282篇 |
3篇 | |
中国医学 | 2880篇 |
肿瘤学 | 74099篇 |
出版年
2021年 | 9007篇 |
2019年 | 9196篇 |
2018年 | 34972篇 |
2017年 | 26822篇 |
2016年 | 29470篇 |
2015年 | 13379篇 |
2014年 | 17670篇 |
2013年 | 26316篇 |
2012年 | 41027篇 |
2011年 | 56154篇 |
2010年 | 39129篇 |
2009年 | 30877篇 |
2008年 | 51833篇 |
2007年 | 55696篇 |
2006年 | 36073篇 |
2005年 | 36348篇 |
2004年 | 36519篇 |
2003年 | 36114篇 |
2002年 | 33076篇 |
2001年 | 49031篇 |
2000年 | 50356篇 |
1999年 | 42052篇 |
1998年 | 11954篇 |
1997年 | 10696篇 |
1996年 | 10631篇 |
1995年 | 10218篇 |
1994年 | 9475篇 |
1993年 | 8817篇 |
1992年 | 33158篇 |
1991年 | 32287篇 |
1990年 | 31862篇 |
1989年 | 30594篇 |
1988年 | 27805篇 |
1987年 | 27972篇 |
1986年 | 25997篇 |
1985年 | 25124篇 |
1984年 | 18776篇 |
1983年 | 15820篇 |
1982年 | 9495篇 |
1979年 | 17104篇 |
1978年 | 12434篇 |
1977年 | 10495篇 |
1976年 | 9917篇 |
1975年 | 10356篇 |
1974年 | 12549篇 |
1973年 | 12045篇 |
1972年 | 11094篇 |
1971年 | 10309篇 |
1970年 | 9568篇 |
1969年 | 8923篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Elizabeth D. Krebs Robert B. Hawkins J. Hunter Mehaffey Clifford E. Fonner Alan M. Speir Mohammed A. Quader Jeffrey B. Rich Leora T. Yarboro Nicholas R. Teman Gorav Ailawadi 《The Journal of thoracic and cardiovascular surgery》2019,157(4):1533-1542.e2
Objectives
Expedient extubation after cardiac surgery has been associated with improved outcomes, leading to postoperative extubation frequently during overnight hours. However, recent evidence in a mixed medical-surgical intensive care unit population demonstrated worse outcomes with overnight extubation. This study investigated the impact of overnight extubation in a statewide, multicenter Society of Thoracic Surgeons database.Methods
Records from 39,812 patients undergoing coronary artery bypass grafting or valve operations (2008-2016) and extubated within 24 hours were stratified according to extubation time between 06:00 and 18:00 (day) or between 18:00 and 6:00 (overnight). Outcomes including reintubation, mortality, and composite morbidity-mortality were evaluated using hierarchical regression models adjusted for Society of Thoracic Surgeons predictive risk scores. To further analyze extubation during the night, a subanalysis stratified patients into 3 groups: 06:00 to 18:00, 18:00 to 24:00, and 24:00 to 06:00.Results
A total of 20,758 patients were extubated overnight (52.1%) and were slightly older (median age 66 vs 65 years, P < .001) with a longer duration of ventilation (4 vs 7 hours, P < .001). Day and overnight extubation were associated with equivalent operative mortality (1.7% vs 1.7%, P = .880), reintubation (3.7% vs 3.4%, P = .141), and composite morbidity-mortality (8.2% vs 8.0%, P = .314). After risk adjustment, overnight extubation was not associated with any difference in reintubation, mortality, or composite morbidity-mortality. On subanalysis, those extubated between 24:00 and 06:00 exhibited increased composite morbidity-mortality (odds ratio, 1.18; P = .001) but no difference in reintubation or mortality.Conclusions
Extubation overnight was not associated with increased mortality or reintubation. These results suggest that in the appropriate clinical setting, it is safe to routinely extubate cardiac surgery patients overnight. 相似文献6.
Ali Mobasheri Csaba Matta Ilona Uzielienè Emma Budd Pablo Martín-Vasallo Eiva Bernotiene 《Joint, bone, spine : revue du rhumatisme》2019,86(1):29-35
Chondrocytes are the main cells in the extracellular matrix (ECM) of articular cartilage and possess a highly differentiated phenotype that is the hallmark of the unique physiological functions of this specialised load-bearing connective tissue. The plasma membrane of articular chondrocytes contains a rich and diverse complement of membrane proteins, known as the membranome, which defines the cell surface phenotype of the cells. The membranome is a key target of pharmacological agents and is important for chondrocyte function. It includes channels, transporters, enzymes, receptors, and anchors for intracellular, cytoskeletal and ECM proteins and other macromolecular complexes. The chondrocyte channelome is a sub-compartment of the membranome and includes a complete set of ion channels and porins expressed in these cells. Many of these are multi-functional proteins with “moonlighting” roles, serving as channels, receptors and signalling components of larger molecular assemblies. The aim of this review is to summarise our current knowledge of the fundamental aspects of the chondrocyte channelome, discuss its relevance to cartilage biology and highlight its possible role in the pathogenesis of osteoarthritis (OA). Excessive and inappropriate mechanical loads, an inflammatory micro-environment, alternative splicing of channel components or accumulation of basic calcium phosphate crystals can result in an altered chondrocyte channelome impairing its function. Alterations in Ca2+ signalling may lead to defective synthesis of ECM macromolecules and aggravated catabolic responses in chondrocytes, which is an important and relatively unexplored aspect of the complex and poorly understood mechanism of OA development. 相似文献
7.
B Maybury A Powell-Chandler N Kumar 《Annals of the Royal College of Surgeons of England》2015,97(3):e37-e38
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.
9.
Seyed Mehdi BagheriMofidi Majid Pouladian Seyed Behnamedin Jameie Ali Abbaspour Tehrani-Fard 《Australasian physical & engineering sciences in medicine / supported by the Australasian College of Physical Scientists in Medicine and the Australasian Association of Physical Sciences in Medicine》2016,39(3):717-726
Magnetic field generated by neuronal activity could alter magnetic resonance imaging (MRI) signals but detection of such signal is under debate. Previous researches proposed that magnitude signal change is below current detectable level, but phase signal change (PSC) may be measurable with current MRI systems. Optimal imaging parameters like echo time, voxel size and external field direction, could increase the probability of detection of this small signal change. We simulate a voxel of cortical column to determine effect of such parameters on PSC signal. We extended a laminar network model for somatosensory cortex to find neuronal current in each segment of pyramidal neurons (PN). 60,000 PNs of simulated network were positioned randomly in a voxel. Biot–savart law applied to calculate neuronal magnetic field and additional phase. The procedure repeated for eleven neuronal arrangements in the voxel. PSC signal variation with the echo time and voxel size was assessed. The simulated results show that PSC signal increases with echo time, especially 100/80 ms after stimulus for gradient echo/spin echo sequence. It can be up to 0.1 mrad for echo time = 175 ms and voxel size = 1.48 × 1.48 × 2.18 mm3. With echo time less than 25 ms after stimulus, it was just acquired effects of physiological noise on PSC signal. The absolute value of the signal increased with decrease of voxel size, but its components had complex variation. External field orthogonal to local surface of cortex maximizes the signal. Expected PSC signal for tactile detection in the somatosensory cortex increase with echo time and have no oscillation. 相似文献
10.