全文获取类型
收费全文 | 150179篇 |
免费 | 45530篇 |
国内免费 | 1320篇 |
专业分类
耳鼻咽喉 | 2409篇 |
儿科学 | 6071篇 |
妇产科学 | 1090篇 |
基础医学 | 27955篇 |
口腔科学 | 7304篇 |
临床医学 | 17828篇 |
内科学 | 32092篇 |
皮肤病学 | 6045篇 |
神经病学 | 20537篇 |
特种医学 | 6822篇 |
外国民族医学 | 1篇 |
外科学 | 16631篇 |
综合类 | 5823篇 |
现状与发展 | 3篇 |
一般理论 | 8篇 |
预防医学 | 11963篇 |
眼科学 | 1815篇 |
药学 | 15505篇 |
28篇 | |
中国医学 | 3799篇 |
肿瘤学 | 13300篇 |
出版年
2024年 | 48篇 |
2023年 | 446篇 |
2022年 | 1017篇 |
2021年 | 2940篇 |
2020年 | 7133篇 |
2019年 | 12349篇 |
2018年 | 11964篇 |
2017年 | 13201篇 |
2016年 | 12314篇 |
2015年 | 12309篇 |
2014年 | 13186篇 |
2013年 | 13750篇 |
2012年 | 12634篇 |
2011年 | 12664篇 |
2010年 | 10905篇 |
2009年 | 7279篇 |
2008年 | 7905篇 |
2007年 | 6377篇 |
2006年 | 5848篇 |
2005年 | 5542篇 |
2004年 | 5140篇 |
2003年 | 4633篇 |
2002年 | 4196篇 |
2001年 | 3379篇 |
2000年 | 2112篇 |
1999年 | 960篇 |
1998年 | 593篇 |
1997年 | 596篇 |
1996年 | 536篇 |
1995年 | 530篇 |
1994年 | 471篇 |
1993年 | 376篇 |
1992年 | 418篇 |
1991年 | 386篇 |
1990年 | 308篇 |
1989年 | 313篇 |
1988年 | 300篇 |
1987年 | 274篇 |
1986年 | 227篇 |
1985年 | 252篇 |
1984年 | 195篇 |
1983年 | 159篇 |
1982年 | 176篇 |
1981年 | 137篇 |
1980年 | 118篇 |
1979年 | 88篇 |
1978年 | 77篇 |
1977年 | 63篇 |
1976年 | 48篇 |
1975年 | 37篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
101.
Stress Testing Versus CT Angiography in Patients With Diabetes and Suspected Coronary Artery Disease
Abhinav Sharma Adrian Coles Nishant K. Sekaran Neha J. Pagidipati Michael T. Lu Daniel B. Mark Kerry L. Lee Hussein R. Al-Khalidi Udo Hoffmann Pamela S. Douglas 《Journal of the American College of Cardiology》2019,73(8):893-902
Background
The optimal noninvasive test (NIT) for patients with diabetes and stable symptoms of coronary artery disease (CAD) is unknown.Objectives
The purpose of this study was to assess whether a diagnostic strategy based on coronary computed tomographic angiography (CTA) is superior to functional stress testing in reducing adverse cardiovascular (CV) outcomes (CV death or myocardial infarction [MI]) among symptomatic patients with diabetes.Methods
PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) was a randomized trial evaluating an initial strategy of CTA versus functional testing in stable outpatients with symptoms suggestive of CAD. The study compared CV outcomes in patients with diabetes (n = 1,908 [21%]) and without diabetes (n = 7,058 [79%]) based on their randomization to CTA or functional testing.Results
Patients with diabetes (vs. without) were similar in age (median 61 years vs. 60 years) and sex (female 54% vs. 52%) but had a greater burden of CV comorbidities. Patients with diabetes who underwent CTA had a lower risk of CV death/MI compared with functional stress testing (CTA: 1.1% [10 of 936] vs. stress testing: 2.6% [25 of 972]; adjusted hazard ratio: 0.38; 95% confidence interval: 0.18 to 0.79; p = 0.01). There was no significant difference in nondiabetic patients (CTA: 1.4% [50 of 3,564] vs. stress testing: 1.3% [45 of 3,494]; adjusted hazard ratio: 1.03; 95% confidence interval: 0.69 to 1.54; p = 0.887; interaction term for diabetes p value = 0.02).Conclusions
In diabetic patients presenting with stable chest pain, a CTA strategy resulted in fewer adverse CV outcomes than a functional testing strategy. CTA may be considered as the initial diagnostic strategy in this subgroup. (PROspective Multicenter Imaging Study for Evaluation of Chest Pain [PROMISE]; NCT01174550) 相似文献102.
A typical time series in functional magnetic resonance imaging (fMRI) exhibits autocorrelation, that is, the samples of the time series are dependent. In addition, temporal filtering, one of the crucial steps in preprocessing of functional magnetic resonance images, induces its own autocorrelation. While performing connectivity analysis in fMRI, the impact of the autocorrelation is largely ignored. Recently, autocorrelation has been addressed by variance correction approaches, which are sensitive to the sampling rate. In this article, we aim to investigate the impact of the sampling rate on the variance correction approaches. Toward this end, we first derived a generalized expression for the variance of the sample Pearson correlation coefficient (SPCC) in terms of the sampling rate and the filter cutoff frequency, in addition to the autocorrelation and cross‐covariance functions of the time series. Through simulations, we illustrated the importance of the variance correction for a fixed sampling rate. Using the real resting state fMRI data sets, we demonstrated that the data sets with higher sampling rates were more prone to false positives, in agreement with the existing empirical reports. We further demonstrated with single subject results that for the data sets with higher sampling rates, the variance correction strategy restored the integrity of true connectivity. 相似文献
103.
Bernard Natukunda Grace Ndeezi Lay See Er Francis Bajunirwe Gayle Teramura Meghan Delaney 《ISBT科学丛刊》2019,14(4):366-373
104.
105.
Judith Brock Andreas Schmid Thomas Karrasch Petra Pfefferle Jutta Schlegel Inga Busse Annette Hauenschild Barbara Schmidt Maria Koukou Efthymia Arapogianni Andreas Schultz Miriam Thomalla Secil Akinci Johannes Kruse Winfried Padberg Andreas Schffler Jens Albrecht 《Clinical endocrinology》2019,91(3):400-410
106.
To increase the overall rate of breastfeeding initiation and duration, factors involved in a mother's decision to breastfeed must be identified. Self‐objectification in the context of breastfeeding was a concept selected for exploring factors associated with negative views of breastfeeding. A concept analysis following the eight‐step Walker & Avant method provides clarity and context to the concept of self‐objectification in the context of breastfeeding. The antecedents of self‐objectification in the context of breastfeeding include living in a culture of sexualization and objectification of women and the internalization of the values of objectification. Attributes of self‐objectification in the context of breastfeeding are a prioritization of physical appearance attributes of the breast over the health benefits of breastfeeding and a preoccupation with physical appearance. Consequences include negative views toward breastfeeding initiation, duration, and public breastfeeding. A concept analysis on self‐objectification in the context of breastfeeding will provide definition and clarity to this phenomenon, lend to theory and measurement, and add literature to the sociocultural factors impacting breastfeeding decisions. 相似文献
107.
目的:观察稀土化合物硝酸钇[Y(NO3)3]亚慢性(90 d)暴露对大鼠学习记忆能力的影响,并探究其可能的机制,为全面评估稀土元素钇的健康风险提供科学依据。方法:选用刚离乳(PND21)SD雌性大鼠,根据质量随机分为4组,分别为对照组(ddH2O),Y(NO3)3低剂量组[10 mg/(kg·d)]、中剂量组[40 mg/(kg·d)]和高剂量组[160 mg/(kg·d)],每组15只。连续灌胃受试物90 d后进行旷场实验、高架十字迷宫实验、转棒实验、Morris水迷宫实验。水迷宫检测后,每组取5只雌鼠心脏原位灌注,进行脑组织病理学检查。每组剩余10只雌鼠摘取脑组织,紫外分光光度计检测雌鼠大脑皮质和海马中谷氨酸(Glu)的含量;Western blot检测海马组织中N-甲基-D-天冬氨酸(NMDA)受体蛋白表达情况。结果:与对照组相比,硝酸钇90 d暴露后,转棒实验中160 mg/(kg·d)剂量组大鼠在棒时间、在棒圈数、掉落速度明显升高(P<0.05)。在Morris水迷宫定位航向实验第4天时,40、160 mg/(kg·d)剂量组大鼠逃避潜伏期明显降低(P<0.05);Morris水迷宫空间探索实验中,40 mg/(kg·d)剂量组大鼠穿越平台次数、目标象限游泳时间明显增加(P<0.05);160 mg/(kg·d)剂量组穿越平台次数、进入目标象限次数、目标象限游泳时间明显增加(P<0.05);160 mg/(kg·d)剂量组大鼠东北、东南、西南象限的逃避潜伏期明显低于西北象限的逃避潜伏期(P<0.05)。160 mg/(kg·d)剂量组大鼠海马中Glu含量和NMDA受体NR1含量均明显低于对照组(P<0.05)。40和160 mg/(kg·d)剂量组大鼠海马中NMDA受体NR2A含量明显低于对照组(P<0.05)。结论:硝酸钇亚慢性(90 d)暴露可以引起雌性大鼠空间学习记忆能力增强;硝酸钇可能通过降低海马组织神经元细胞外Glu含量,抑制NMDA受体激活,增强雌性大鼠的空间学习记忆能力。 相似文献
108.
Elevated serum levels of Interleukin‐37 are associated with inflammatory cytokines and disease activity in rheumatoid arthritis
下载免费PDF全文
![点击此处可从《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Libin Yang Jun Zhang Jingang Tao Tan Lu 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2015,123(12):1025-1031
Interleukin‐37 (IL‐37) is closely associated with several inflammatory diseases. However, the role of IL‐37 in the pathogenesis of rheumatoid arthritis (RA) remains unclear. The aim of this study was to assess the associations between serum levels of IL‐37 and disease activity, inflammatory cytokines, and bone loss in patients with RA. Serum cytokines levels were examined by Enzyme‐linked immunosorbent assay (ELISA). Radiographic bone erosion was assessed using the van der Heijde‐modified Sharp score and bone mineral density (BMD) was measured using DXA. Serum IL‐37 levels in RA patients were significantly higher than those in HCs (p < 0.001), and were significantly positively correlated with clinical parameters of disease activity and serum levels of IL‐17 and IL‐23. In addition, serum IL‐37 levels were significantly higher in patients with stage IV of radiographic bone erosion than those with stage III and stage I–II, and they were significantly higher in those with osteopenia and osteoporosis than in those with normal BMD. Our results suggest that serum IL‐37 levels were increased in patients with RA and were positively associated with disease activity, IL‐17/IL‐23 and bone loss in RA, suggesting that IL‐37 may play a critical role in the pathogenesis of RA. 相似文献
109.