全文获取类型
收费全文 | 3529篇 |
免费 | 196篇 |
国内免费 | 23篇 |
专业分类
耳鼻咽喉 | 79篇 |
儿科学 | 94篇 |
妇产科学 | 80篇 |
基础医学 | 544篇 |
口腔科学 | 57篇 |
临床医学 | 290篇 |
内科学 | 754篇 |
皮肤病学 | 76篇 |
神经病学 | 364篇 |
特种医学 | 129篇 |
外科学 | 245篇 |
综合类 | 24篇 |
预防医学 | 281篇 |
眼科学 | 64篇 |
药学 | 418篇 |
中国医学 | 10篇 |
肿瘤学 | 239篇 |
出版年
2024年 | 4篇 |
2023年 | 48篇 |
2022年 | 186篇 |
2021年 | 273篇 |
2020年 | 91篇 |
2019年 | 142篇 |
2018年 | 158篇 |
2017年 | 115篇 |
2016年 | 135篇 |
2015年 | 128篇 |
2014年 | 171篇 |
2013年 | 220篇 |
2012年 | 288篇 |
2011年 | 282篇 |
2010年 | 149篇 |
2009年 | 129篇 |
2008年 | 169篇 |
2007年 | 221篇 |
2006年 | 209篇 |
2005年 | 182篇 |
2004年 | 153篇 |
2003年 | 113篇 |
2002年 | 101篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 5篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 5篇 |
1995年 | 6篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 4篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有3748条查询结果,搜索用时 15 毫秒
71.
Ivan Stankovic Aleksandra Janicijevic Aleksandra Dimic Milica Stefanovic Radosav Vidakovic Biljana Putnikovic 《Annals of medicine》2018,50(2):128-138
Objectives: Bundle branch blocks (BBB)-related mechanical dyssynchrony and dispersion may improve patient selection for device therapy, but their effect on the natural history of this patient population is unknown.Methods: A total of 155 patients with LVEF?≤?35% and BBB, not treated with device therapy, were included. Mechanical dyssynchrony was defined as the presence of either septal flash or apical rocking. Contraction duration was assessed as time interval from the electrocardiographic R-(Q-)wave to peak longitudinal strain in each of 17 left ventricular segments. Mechanical dispersion was defined as either the standard deviation of all time intervals (dispersionSD) or as the difference between the longest and shortest time intervals (dispersiondelta). Patients were followed for cardiac mortality during a median period of 33 months.Results: Mechanical dyssynchrony was not associated with survival. More pronounced mechanical dispersiondelta was found in patients with dyssynchrony than in those without. In the multivariate regression analysis, patients’ functional class, diabetes mellitus and dispersiondelta were independently associated with mortality.Conclusions: Mechanical dispersion, but not dyssynchrony, was independently associated with mortality and it may be useful for risk stratification of patients with heart failure (HF) and BBB.
- Key Messages
Mechanical dispersion, measured by strain echocardiography, is associated with poor outcome in heart failure with a severely depressed left ventricular function and bundle branch blocks.
Mechanical dispersion may be useful for risk stratification of patients with heart failure and bundle branch blocks.
72.
73.
Heikkinen Aki T. Friedlein Arno Matondo Mariette Hatley Oliver J. D. Petsalo Aleksanteri Juvonen Risto Galetin Aleksandra Rostami-Hodjegan Amin Aebersold Ruedi Lamerz Jens Dunkley Tom Cutler Paul Parrott Neil 《Pharmaceutical research》2015,32(1):74-90
Pharmaceutical Research - Beagle dogs are used to study oral pharmacokinetics and guide development of drug formulations for human use. Since mechanistic insight into species differences is needed... 相似文献
74.
Ivan Ranković Vladimir Milivojević Aleksandra PavlovićMarković Mihailo Bezmarević 《World journal of gastroenterology : WJG》2022,28(4):497-499
Elaboration of carotid atherosclerosis in the setting of hepatitis B virus(HBV)infection should emphasize the significance of extrahepatic manifestations of the infection pathogenesis.Diverse processes comprise the pathoevolution of HBV infection,rendering it a multi-systemic disease in its essence.Our work not only exemplified atherosclerosis as an often-underestimated contributor to the severity of HBV infection but has also highlighted the bidirectional relationship between the two.Therefore,it is suggested that HBV-induced inflammation is one of the root causes of atherosclerosis,which in turn has a consequent effect on the severity of the chronic infection disease state,creating a vicious cycle.Additionally,we coupled prior data with the current concepts of HBV infection to postulate intriguing perspectives and theories. 相似文献
75.
The role of CGRP and afferent nerves in the modulation of pancreatic enzyme secretion in the rat 总被引:1,自引:0,他引:1
Jolanta Jaworek Stanisaw J. Konturek Aleksandra Szlachcic 《Journal of gastrointestinal cancer》1997,22(2):137-146
Summary
Conclusion Stimulation of pancreatic sensory nerves by capsaicin produced secretory effects probably caused, at least in part, by the
release of CGRP.
Background In the pancreas calcitonin gene-related peptide (CGRP) has been localized in the sensory nerves, but its physiological role
is unknown. This study was undertaken to compare the changes of pancreatic enzyme secretion produced by CGRP and by stimulation
or destruction of sensory nerves.
Methods To stimulate sensory nerves, low doses of capsaicin (0.25–0.5 mg/kg) were given intraduodenally to the conscious rats with
chronic pancreatic fistula. To inactivate sensory nerves high doses of capsaicin (100 mg/kg) were given subcutaneously 10
d before tests. For the in vitro experiments pancreatic slices and isolated pancreatic acini were prepared from intact and
capsaicin-denervated rats.
Results In conscious rats, CGRP given subcutaneously (5–10 μg/kg) and low doses of capsaicin given intraduodenally reduced basal pancreatic
secretion. In isolated pancreatic acini, CGRP (10−10–10−6
M), but not capsaicin, increased basal or secretagog-stimulated amylase release. In pancreatic slices (containing nerve fibers)
capsaicin (10−10–10−6
M) increased enzyme secretion, and this secretion was abolished by previous inactivation of sensory nerves by this neurotoxin.
Capsaicin deactivation did not affect the secretory response of pancreatic acini to CGRP, cerulein, or urecholine. Sensory
denervation by capsaicin did not change basal protein secretion, but reduced that produced by feeding or diversion of pancreatic
juice to the exterior during first 2 h of the tests. 相似文献
76.
The primary identified function of complement receptor 1 (CR1/CD35) on primate erythrocytes is to bind complement-tagged inflammatory particles including microbes and immune complexes. When erythrocytes circulate through liver and spleen, sinusoidal phagocytes remove CR1-adherent particles and erythrocytes return to the circulation. This process of immune adherence clearance is important for host defense and prevention of autoimmunity. CR1 was previously described as clustered in the human erythrocyte membrane, which was thought to be necessary for binding complement-opsonized particles. In contrast, we demonstrate that on erythrocytes CR1 is not clustered, but dispersed, and able to bind complement-tagged particles. When fresh erythrocytes are solubilized by nonionic detergent, CR1 partitions to the cytoskeleton fraction. Using a PDZ-peptide array, CR1's cytoplasmic tail, which contains 2 PDZ-motifs, binds PDZ domains 2, 3, and 5 of Fas-associated phosphatase 1 (FAP-1), a scaffolding protein. We show that FAP-1, not previously recognized as an erythroid protein, is expressed on circulating erythrocytes. CR1 and FAP-1 coimmunoprecipitate, which confirms their molecular association. Disperse CR1 on erythrocytes may be advantageous for capturing immune-complexes, while ligation-induced CR1 clustering may prevent ingestion of the erythrocyte during the immune-complex transfer to the macrophages by keeping the opsonic stimulus localized thus preventing phagocyosis. 相似文献
77.
Przybylski G Jarzemska A Czerniak J Siemiatkowska K Gadzińska A Cieśliński K 《Polskie Archiwum Medycyny Wewn?trznej》2008,118(3):143-147
Dermatomyositis (DM) is a connective tissue disease characterized by specific inflammatory lesions in muscle biopsy. It is caused by vasculitis determined by humoral factors with subsequent inflammatory cell accumulation, mainly T CD4+ and B cells, which infiltrate myocytes leading to its vacuolization and degeneration (mainly in the skeletal muscles, rarely in the smooth muscles). The incidence of DM is estimated at 1-10 per million in adults and at 1-3.2 per million in children. The autoimmune mechanism of disease induction is not fully recognized. Several lines of evidence showed the link between DM and neoplastic disease. The first report of dermatomyositis associated with stomach cancer, by Stertz, comes from 1916. In the same time, Kankeleit reported DM associated with breast cancer. Presumably, it is the result of immune reaction against antigens common for muscle and neoplastic cells or some paraneoplastic syndrome underlying mechanism. The report presents the case of a 52-year-old woman with DM (diagnosed according to the Bohan and Peter criteria) and with coexistent squamous lung cancer in situ. The left upper lobectomy was performed. No complications in postoperative period were observed. During more than 2 years of follow-up after the surgery, the patient remained in good condition, without DM symptoms, or cancer relapse. Considering that DM may be associated with lung cancer; extensive diagnostic work-up to exclude neoplastic lesions should be performed. Patients aged 40 years or more should be particularly screened. 相似文献
78.
John D. Biglands Montasir Ibraheem Derek R. Magee Aleksandra Radjenovic Sven Plein John P. Greenwood 《JACC: Cardiovascular Imaging》2018,11(5):711-718
Objectives
This study sought to compare the diagnostic accuracy of visual and quantitative analyses of myocardial perfusion cardiovascular magnetic resonance against a reference standard of quantitative coronary angiography.Background
Visual analysis of perfusion cardiovascular magnetic resonance studies for assessing myocardial perfusion has been shown to have high diagnostic accuracy for coronary artery disease. However, only a few small studies have assessed the diagnostic accuracy of quantitative myocardial perfusion.Methods
This retrospective study included 128 patients randomly selected from the CE-MARC (Clinical Evaluation of Magnetic Resonance Imaging in Coronary Heart Disease) study population such that the distribution of risk factors and disease status was proportionate to the full population. Visual analysis results of cardiovascular magnetic resonance perfusion images, by consensus of 2 expert readers, were taken from the original study reports. Quantitative myocardial blood flow estimates were obtained using Fermi-constrained deconvolution. The reference standard for myocardial ischemia was a quantitative coronary x-ray angiogram stenosis severity of ≥70% diameter in any coronary artery of >2 mm diameter, or ≥50% in the left main stem. Diagnostic performance was calculated using receiver-operating characteristic curve analysis.Results
The area under the curve for visual analysis was 0.88 (95% confidence interval: 0.81 to 0.95) with a sensitivity of 81.0% (95% confidence interval: 69.1% to 92.8%) and specificity of 86.0% (95% confidence interval: 78.7% to 93.4%). For quantitative stress myocardial blood flow the area under the curve was 0.89 (95% confidence interval: 0.83 to 0.96) with a sensitivity of 87.5% (95% confidence interval: 77.3% to 97.7%) and specificity of 84.5% (95% confidence interval: 76.8% to 92.3%). There was no statistically significant difference between the diagnostic performance of quantitative and visual analyses (p = 0.72). Incorporating rest myocardial blood flow values to generate a myocardial perfusion reserve did not significantly increase the quantitative analysis area under the curve (p = 0.79).Conclusions
Quantitative perfusion has a high diagnostic accuracy for detecting coronary artery disease but is not superior to visual analysis. The incorporation of rest perfusion imaging does not improve diagnostic accuracy in quantitative perfusion analysis. 相似文献79.
Anna Leszczyńska-Rodziewicz Małgorzata Maciukiewicz Aleksandra Szczepankiewicz Andrzej Pogłodziński Joanna Hauser 《Journal of affective disorders》2013
The aim of the study was to investigate the possible association between polymorphisms of HPA axis genes-CRHR1 (corticotrophin-releasing hormone receptor), NR3C1 (glucocorticoid receptor) and AVPR1B (arginine vasopressin receptor) and dimensions of bipolar disorder assessed by OPCRIT. 相似文献
80.
Aleksandra Mielczarek-Palacz Justyna SikoraZdzisława Kondera-Anasz Grzegorz Hauza 《Human immunology》2013
The aim of the study was to examine the concentrations of the soluble receptors and their ligands of CD30/CD30L and CD40/CD40L systems in the serum of women with ovarian tumor and in the ovarian cyst fluid of women with Cystadenoma serosum. The study included 120 women with ovarian tumors. As a control, sera were obtained from 60 healthy female volunteers. Concentrations of the sCD30, sCD30L, sCD40 and sCD40L in the serum and the ovarian cyst fluid were measured by ELISA enzyme-linked immunosorbent assay. Concentrations of both sCD30 and sCD30L in serum of women with ovarian tumors were significantly higher than in control (p < 0.0001). The highest serum receptor and its ligand levels were observed in women with ovarian cancer (p < 0.0001). Moreover, results showed significantly increased levels of sCD40 and sCD40L serum in women with ovarian tumors, as compared to the control group (p < 0.0001). The highest concentration of sCD40 in the serum of women with ovarian cancer and sCD40L in serum of women with Teratoma maturum (p < 0.0001) were observed. Impaired apoptosis among women with ovarian tumors is associated with the impairments of soluble CD30/CD30L and CD40/CD40L systems. Measurement of studied parameter concentrations in serum of women with ovarian tumors has been suggested to be a potential tool in monitoring of inflammatory. Evaluation of sCD30, sCD30L and sCD40 might be an early diagnostic marker in patients with the ovarian cancer. Concentrations of the studied parameters in the ovarian cyst fluid higher than the serum values suggest local suppression of the immune response. However, the final evaluation of the importance of measurement of serum levels of them requires further investigation. 相似文献