全文获取类型
收费全文 | 514622篇 |
免费 | 34073篇 |
国内免费 | 618篇 |
专业分类
耳鼻咽喉 | 6898篇 |
儿科学 | 16859篇 |
妇产科学 | 13549篇 |
基础医学 | 85217篇 |
口腔科学 | 14486篇 |
临床医学 | 44461篇 |
内科学 | 93741篇 |
皮肤病学 | 12207篇 |
神经病学 | 36286篇 |
特种医学 | 18521篇 |
外国民族医学 | 65篇 |
外科学 | 77372篇 |
综合类 | 8479篇 |
一般理论 | 118篇 |
预防医学 | 39080篇 |
眼科学 | 12137篇 |
药学 | 40618篇 |
中国医学 | 1007篇 |
肿瘤学 | 28212篇 |
出版年
2018年 | 4957篇 |
2015年 | 4527篇 |
2014年 | 6102篇 |
2013年 | 9622篇 |
2012年 | 12968篇 |
2011年 | 14367篇 |
2010年 | 8346篇 |
2009年 | 7820篇 |
2008年 | 13774篇 |
2007年 | 14767篇 |
2006年 | 15026篇 |
2005年 | 14435篇 |
2004年 | 14144篇 |
2003年 | 13451篇 |
2002年 | 13359篇 |
2001年 | 24119篇 |
2000年 | 25129篇 |
1999年 | 20604篇 |
1998年 | 5455篇 |
1997年 | 4719篇 |
1996年 | 5050篇 |
1995年 | 4637篇 |
1994年 | 4327篇 |
1993年 | 4143篇 |
1992年 | 15746篇 |
1991年 | 16329篇 |
1990年 | 16442篇 |
1989年 | 15813篇 |
1988年 | 14587篇 |
1987年 | 14445篇 |
1986年 | 13626篇 |
1985年 | 12992篇 |
1984年 | 9643篇 |
1983年 | 8257篇 |
1982年 | 4569篇 |
1981年 | 4236篇 |
1979年 | 9428篇 |
1978年 | 6869篇 |
1977年 | 5782篇 |
1976年 | 5610篇 |
1975年 | 6416篇 |
1974年 | 7648篇 |
1973年 | 7147篇 |
1972年 | 6967篇 |
1971年 | 6695篇 |
1970年 | 6178篇 |
1969年 | 5892篇 |
1968年 | 5565篇 |
1967年 | 5013篇 |
1966年 | 4452篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
31.
32.
Feasibility and Diagnostic Potential of Pulmonary Transit Time Measurement by Contrast Echocardiography: A Pilot Study
下载免费PDF全文
![点击此处可从《Echocardiography (Mount Kisco, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
33.
E. M. Peterman C. Sullivan M. F. Goody I. Rodriguez-Nunez J. A. Yoder C. H. Kim 《Infection and immunity》2015,83(1):430-440
Mitochondria are known primarily as the location of the electron transport chain and energy production in cells. More recently, mitochondria have been shown to be signaling centers for apoptosis and inflammation. Reactive oxygen species (ROS) generated as by-products of the electron transport chain within mitochondria significantly impact cellular signaling pathways. Because of the toxic nature of ROS, mitochondria possess an antioxidant enzyme, superoxide dismutase 2 (SOD2), to neutralize ROS. If mitochondrial antioxidant enzymes are overwhelmed during severe infections, mitochondrial dysfunction can occur and lead to multiorgan failure or death. Pseudomonas aeruginosa is an opportunistic pathogen that can infect immunocompromised patients. Infochemicals and exotoxins associated with P. aeruginosa are capable of causing mitochondrial dysfunction. In this work, we describe the roles of SOD2 and mitochondrial ROS regulation in the zebrafish innate immune response to P. aeruginosa infection. sod2 is upregulated in mammalian macrophages and neutrophils in response to lipopolysaccharide in vitro, and sod2 knockdown in zebrafish results in an increased bacterial burden. Further investigation revealed that phagocyte numbers are compromised in Sod2-deficient zebrafish. Addition of the mitochondrion-targeted ROS-scavenging chemical MitoTEMPO rescues neutrophil numbers and reduces the bacterial burden in Sod2-deficient zebrafish. Our work highlights the importance of mitochondrial ROS regulation by SOD2 in the context of innate immunity and supports the use of mitochondrion-targeted ROS scavengers as potential adjuvant therapies during severe infections. 相似文献
34.
Marcel Toussaint Raymond J. Gilles Noura Azzabou Benjamin Marty Alexandre Vignaud Andreas Greiser Pierre G. Carlier 《Medicine》2015,94(43)
Delayed contrast enhancement after injection of a gadolinium-chelate (Gd-chelate) is a reference imaging method to detect myocardial tissue changes. Its localization within the thickness of the myocardial wall allows differentiating various pathological processes such as myocardial infarction (MI), inflammatory myocarditis, and cardiomyopathies. The aim of the study was first to characterize benign myocarditis using quantitative delayed-enhancement imaging and then to investigate whether the measure of the extracellular volume fraction (ECV) can be used to discriminate between MI and myocarditis.In 6 patients with acute benign myocarditis (32.2 ± 13.8 year-old, subepicardial late gadolinium enhancement [LGE]) and 18 patients with MI (52.3 ± 10.9 year-old, subendocardial/transmural LGE), myocardial T1 was determined using the Modified Look-Locker Imaging (MOLLI) sequence at 3 Tesla before and after Gd-chelate injection. T1 values were compared in LGE and normal regions of the myocardium. The myocardial T1 values were normalized to the T1 of blood, and the ECV was calculated from T1 values of myocardium and blood pre- and post-Gd injection.In both myocarditis and MI, the T1 was lower in LGE regions than in normal regions of the left ventricle. T1 of LGE areas was significantly higher in myocarditis than in MI (446.8 ± 45.8 vs 360.5 ± 66.9 ms, P = 0.003) and ECV was lower in myocarditis than in MI (34.5 ± 3.3 vs 53.8 ± 13.0 %, P = 0.004).Both inflammatory process and chronic fibrosis induce LGE (subepicardial in myocarditis and subendocardial in MI). The present study demonstrates that the determination of T1 and ECV is able to differentiate the 2 histological patterns.Further investigation will indicate whether the severity of ECV changes might help refine the predictive risk of LGE in myocarditis. 相似文献
35.
36.
37.
38.
39.
R.D. Olmos R.C. de Figueiredo E.M. Aquino P.A. Lotufo I.M. Bensenor 《Brazilian journal of medical and biological research》2015,48(8):751-758
Thyroid diseases are common, and use of levothyroxine is increasing worldwide. We
investigated the influence of gender, race and socioeconomic status on the diagnosis
and treatment of thyroid disorders using data from the Brazilian Longitudinal Study
of Adult Health (ELSA-Brasil), a multicenter cohort study of civil servants (35-74
years of age) from six Brazilian cities. Diagnosis of thyroid dysfunction was by
thyrotropin (TSH), and free thyroxine (FT4) if TSH was altered, and the use of
specific medications. Multivariate logistic regression models were constructed using
overt hyperthyroidism/hypothyroidism and levothyroxine use as dependent variables and
sociodemographic characteristics as independent variables. The frequencies of overt
hyper- and hypothyroidism were 0.7 and 7.4%, respectively. Using whites as the
reference ethnicity, brown, and black race were protective for overt hypothyroidism
(OR=0.76, 95%CI=0.64-0.89, and OR=0.53, 95%CI=0.43-0.67, respectively, and black race
was associated with overt hyperthyroidism (OR=1.82, 95%CI=1.06-3.11). Frequency of
hypothyroidism treatment was higher in women, browns, highly educated participants
and those with high net family incomes. After multivariate adjustment, levothyroxine
use was associated with female gender (OR=6.06, 95%CI=3.19-11.49) and high net family
income (OR=3.23, 95%CI=1.02-10.23). Frequency of hyperthyroidism treatment was higher
in older than in younger individuals. Sociodemographic factors strongly influenced
the diagnosis and treatment of thyroid disorders, including the use of
levothyroxine. 相似文献
40.
A novel BRAF mutation in association with primary amelanotic melanoma with oral metastases
下载免费PDF全文
![点击此处可从《Journal of the European Academy of Dermatology and Venereology》网站下载免费的PDF全文](/ch/ext_images/free.gif)