全文获取类型
收费全文 | 5602篇 |
免费 | 378篇 |
国内免费 | 27篇 |
专业分类
耳鼻咽喉 | 25篇 |
儿科学 | 176篇 |
妇产科学 | 154篇 |
基础医学 | 786篇 |
口腔科学 | 99篇 |
临床医学 | 477篇 |
内科学 | 1364篇 |
皮肤病学 | 157篇 |
神经病学 | 489篇 |
特种医学 | 92篇 |
外科学 | 600篇 |
综合类 | 37篇 |
一般理论 | 3篇 |
预防医学 | 674篇 |
眼科学 | 94篇 |
药学 | 354篇 |
中国医学 | 14篇 |
肿瘤学 | 412篇 |
出版年
2023年 | 35篇 |
2022年 | 73篇 |
2021年 | 171篇 |
2020年 | 99篇 |
2019年 | 172篇 |
2018年 | 188篇 |
2017年 | 110篇 |
2016年 | 105篇 |
2015年 | 129篇 |
2014年 | 188篇 |
2013年 | 304篇 |
2012年 | 417篇 |
2011年 | 419篇 |
2010年 | 289篇 |
2009年 | 208篇 |
2008年 | 385篇 |
2007年 | 372篇 |
2006年 | 333篇 |
2005年 | 321篇 |
2004年 | 300篇 |
2003年 | 279篇 |
2002年 | 263篇 |
2001年 | 78篇 |
2000年 | 69篇 |
1999年 | 83篇 |
1998年 | 55篇 |
1997年 | 41篇 |
1996年 | 30篇 |
1995年 | 31篇 |
1994年 | 28篇 |
1993年 | 30篇 |
1992年 | 40篇 |
1991年 | 46篇 |
1990年 | 31篇 |
1989年 | 21篇 |
1988年 | 23篇 |
1987年 | 11篇 |
1986年 | 19篇 |
1985年 | 16篇 |
1984年 | 17篇 |
1983年 | 13篇 |
1982年 | 15篇 |
1981年 | 18篇 |
1980年 | 17篇 |
1978年 | 16篇 |
1976年 | 8篇 |
1975年 | 9篇 |
1973年 | 13篇 |
1971年 | 9篇 |
1967年 | 8篇 |
排序方式: 共有6007条查询结果,搜索用时 15 毫秒
61.
62.
63.
TGF-beta3 regulates the blood-testis barrier dynamics via the p38 mitogen activated protein (MAP) kinase pathway: an in vivo study 总被引:1,自引:0,他引:1
Recent studies using Sertoli cells cultured in vitro to permit tight junction (TJ) assembly have shown that TJ dynamics are regulated, at least in part, by TGF-beta3 via the p38 mitogen activated protein (MAP) kinase pathway. This in turn regulates the production of occludin, a TJ-integral membrane protein, by Sertoli cells. Yet it is not known if this pathways is used by Sertoli cells to regulate the blood-testis barrier (BTB) function in vivo. Using an in vivo model for studying BTB dynamics, we report herein the CdCl(2)-induced BTB damage in rats was associated with a significant reduction in testicular occludin along with a loss of immunoreactive occludin in the seminiferous epithelium at the site of the BTB. Also, this CdCl(2)-induced occludin loss from the BTB coincided with a surge in testicular TGF-beta3, as well as p-p38 MAP kinase (the phosphorylated/activated form of p38), but not p38 MAP kinase and neither extracellular signal-regulated kinase nor its phosphorylated form (ERK/p-ERK), consistent with results of in vitro studies. More important, intratesticular administration of SB202190, a specific p38 MAP kinase inhibitor, could block the CdCl(2)-induced occludin loss from the BTB. These results illustrate that BTB dynamics in vivo are regulated by the TGF-beta3/p38 MAP kinase pathway, which in turn determines the level of occludin at the site of Sertoli cells TJs. 相似文献
64.
Antonio Ramos-Martínez Alejandro Muñoz Serrano Arístides de Alarcón González Patricia Muñoz Ana Fernández-Cruz Maricela Valerio María Carmen Fariñas Manuel Gutiérrez-Cuadra José Ma Miró Josefa Ruiz-Morales Dolores Sousa-Regueiro José Miguel Montejo Juan Gálvez-Acebal Carmen HidalgoTenorio Fernando Domínguez 《Journal of infection and chemotherapy》2018,24(7):555-562
Purpose
To analyze the influence of adding gentamicin to a regimen consisting of β-lactam or vancomycin plus rifampicin on survival in patients suffering from Staphylococcal prosthetic valve endocarditis (SPVE).Methods
From January 2008 to September 2016, 334 patients with definite SPVE were attended in the participating hospitals. Ninety-four patients (28.1%) received treatment based on β-lactam or vancomycin plus rifampicin and were included in the study. Variables were analyzed which related to patient survival during admission, including having received treatment with gentamicin.Results
Seventy-seven (81.9%) were treated with cloxacillin (or vancomycin) plus rifampicin plus gentamicin, and 17 patients (18.1%) received the same regimen without gentamicin. The causative microorganism was Staphylococcus aureus in 40 cases (42.6%) and coagulase-negative staphylococci in 54 cases (57.4%). Overall, 40 patients (42.6%) died during hospital admission, 33 patients (42.9%) in the group receiving gentamicin and 7 patients in the group that did not (41.2%, P = 0.899). Worsening renal function was observed in 42 patients (54.5%) who received gentamicin and in 9 patients (52.9%) who did not (p = 0.904). Heart failure as a complication of endocarditis (OR: 4.58; CI 95%: 1.84–11.42) and not performing surgery when indicated (OR: 2.68; CI 95%: 1.03–6.94) increased mortality. Gentamicin administration remained unrelated to mortality (OR: 1.001; CI 95%: 0.29–3.38) in the multivariable analysis.Conclusions
The addition of gentamicin to a regimen containing vancomycin or cloxacillin plus rifampicin in SPVE was not associated to better outcome. 相似文献65.
The functional immaturity of dendritic cells can be relevant to increased tolerance associated with cord blood transplantation 总被引:4,自引:0,他引:4
BACKGROUND: Cord blood (CB) transplants have a significantly lower incidence of graft-versus-host disease (GVHD) compared to marrow or peripheral blood transplants. Because antigen-presenting cells and regulatory T cells (Treg) are involved in transplant tolerance, this study was aimed at analyzing the distribution of dendritic cells (DCs) and CD14+ monocyte-specific subsets in CB and adult peripheral blood (APB) and comparing the ability of DCs from these two blood sources to induce CD4+ Treg. STUDY DESIGN AND METHODS: Myeloid DCs (mDCs), plasmacytoid DCs, the CD14+ cell subsets CD14+CD16+ and CD14+CD209+, and CD4+ T cells were analyzed by fluorescence-activated cell sorting (FACS) in whole blood. To evaluate the functionality of DCs, isolated CD3+ T cells from an adult donor were cultured with allogenic DC-enriched fraction from CB or APB, and CD4+ Treg generation was determined by FACS. Additionally, tumor necrosis factor (TNF)-alpha and interferon (IFN)-alpha release by DCs was measured. RESULTS: CB had a lesser frequency of DCs and specific CD14+ monocyte subsets than APB. After stimulation, monocytes from CB secreted less TNF-alpha than those from APB. Moreover, DCs from CB exhibited a more immature phenotype and had a decreased capacity to release TNF-alpha and IFN-alpha than those derived from APB, but on the contrary, they were efficient inducers of CD4+ T cells with a phenotype of Treg. CONCLUSION: The tolerogenic immunophenotype and diminished functionality of CB DCs can be important to create a microenvironment where Treg develop, that in turn may be relevant to observed lower incidence of chronic GVHD after CB transplantation. 相似文献
66.
Bilateral abscessed orchiepididymitis associated with sepsis caused by Veillonella parvula and Clostridium perfringens: case report and review of the literature. 下载免费PDF全文
P M Arrosagaray C Salas M Morales M Correas J M Barros M L Cordon 《Journal of clinical microbiology》1987,25(8):1579-1580
Veillonella species is a gram-negative coccus which is part of the anaerobic normal flora in the oral cavity, small intestine, upper respiratory tract, vagina, and urinary tract. The role that this organism plays in infection is not well known, and it is generally associated with other bacteria. We present a case of bilateral abscessed orchiepididymitis associated with septicemia due to Veillonella parvula and, later, to Clostridium perfringens, with the development of severe renal insufficiency and septic shock, which resolved favorably with antibiotic therapy, treatment of shock, and hyperbaric oxygen therapy. In reviewing the literature, we have not found any other case of sepsis due to Veillonella sp. associated with urological disorders. 相似文献
67.
Hartl D Griese M Nicolai T Zissel G Prell C Konstantopoulos N Gruber R Reinhardt D Schendel DJ Krauss-Etschmann S 《The Journal of allergy and clinical immunology》2005,115(4):728-736
BACKGROUND: Cough is a frequent symptom in children, but the differentiation of asthmatic cough from cough of other origins can be difficult. Chemokines recruit T lymphocytes to inflamed tissues, and the corresponding chemokine receptors are differentially expressed on T H 1 and T H 2 cells. OBJECTIVE: We sought to determine whether levels of T H 1/T H 2-related chemokines and their receptors differ in bronchoalveolar lavage fluid (BALF) from 12 children with allergic asthma, 15 nonatopic children with chronic cough, and 10 children without airway disease. METHODS: The T H 1-related (IFN-gamma-inducible protein of 10 kd [IP-10], IFN-gamma-inducible T cell alpha chemoattractant [ITAC], monokine induced by IFN-gamma [Mig], and IFN-gamma) and T H 2-related (thymus- and activation-regulated chemokine [TARC], macrophage-derived chemokine [MDC], IL-5, and IL-4) chemokines and cytokines were quantified in BALF by ELISA and a particle-based multiplex array. Percentages of pulmonary lymphocytes expressing CXCR3 + and CCR5 + (T H 1) and CCR4 + and CCR3 + (T H 2) chemokine receptors were determined in BALF by flow cytometry. RESULTS: Pulmonary CCR4 + CD4 + cells and levels of TARC and MDC were significantly increased in asthmatic children versus children with chronic cough or without airway disease. In asthmatic children CCR4 + CD4 + cells correlated positively with levels of TARC, MDC, and serum IgE levels and negatively with FEV 1 . In contrast, CXCR3 + CD8 + cells and levels of ITAC were significantly increased in children with non-atopic chronic cough compared with the other groups. In children with chronic cough, CXCR3 + CD8 + cells correlated with levels of ITAC and IFN-gamma. CONCLUSION: Pulmonary CCR4 + CD4 + and CXCR3 + CD8 + cells and their ligands TARC, MDC, and ITAC clearly differentiate asthmatic children from nonatopic children with chronic cough. The analysis of these markers could facilitate the diagnostic discrimination of asthma versus other reasons for chronic cough in children. 相似文献
68.
Cytogenomic and phenotypic analysis in low‐level monosomy 7 mosaicism with non‐supernumerary ring chromosome 7 下载免费PDF全文
Consuelo Salas‐Labadía David E. Cervantes‐Barragán Roberto Cruz‐Alcívar Robert D. Daber Laura K. Conlin Laura D. Leonard Nancy B. Spinner Carola Durán‐McKinster David J. Dávila‐Ortíz de Montellano Victoria Del Castillo‐Ruiz Patricia Pérez‐Vera 《American journal of medical genetics. Part A》2014,164(7):1765-1769
69.
We propose a model of an equivalent electrical circuit specifically designed for a ferrite indAuctor excited by a sinusoidal waveform. The purpose of this model is its use in a circuit simulator. We calculate the model parameters by means of Finite Elements in 2D which leads to significant computational advantages over the 3D model. We carry out the validation for a toroidal ferrite inductor by comparing the experimental results and computed ones. We consider the saturation and power losses in the core. In addition, we have tested the model for the case of square waveform in order to generalize the results. We find excellent agreement between the experimental data and the results obtained by numerical calculations. 相似文献
70.
Alfonso Rubio‐Navarro Maria Dolores Sanchez‐Niño Melania Guerrero‐Hue Cristina García‐Caballero Eduardo Gutiérrez Claudia Yuste Ángel Sevillano Manuel Praga Javier Egea Elena Román Pablo Cannata Rosa Ortega Isabel Cortegano Belén de Andrés María Luisa Gaspar Susana Cadenas Alberto Ortiz Jesús Egido Juan Antonio Moreno 《The Journal of pathology》2018,244(3):296-310
Recurrent and massive intravascular haemolysis induces proteinuria, glomerulosclerosis, and progressive impairment of renal function, suggesting podocyte injury. However, the effects of haemoglobin (Hb) on podocytes remain unexplored. Our results show that cultured human podocytes or podocytes isolated from murine glomeruli bound and endocytosed Hb through the megalin–cubilin receptor system, thus resulting in increased intracellular Hb catabolism, oxidative stress, activation of the intrinsic apoptosis pathway, and altered podocyte morphology, with decreased expression of the slit diaphragm proteins nephrin and synaptopodin. Hb uptake activated nuclear factor erythroid‐2‐related factor 2 (Nrf2) and induced expression of the Nrf2‐related antioxidant proteins haem oxygenase‐1 (HO‐1) and ferritin. Nrf2 activation and Hb staining was observed in podocytes of mice with intravascular haemolysis. These mice developed proteinuria and showed podocyte injury, characterized by foot process effacement, decreased synaptopodin and nephrin expression, and podocyte apoptosis. These pathological effects were enhanced in Nrf2‐deficient mice, whereas Nrf2 activation with sulphoraphane protected podocytes against Hb toxicity both in vivo and in vitro. Supporting the translational significance of our findings, we observed podocyte damage and podocytes stained for Hb, HO‐1, ferritin and phosphorylated Nrf2 in renal sections and urinary sediments of patients with massive intravascular haemolysis, such as atypical haemolytic uraemic syndrome and paroxysmal nocturnal haemoglobinuria. In conclusion, podocytes take up Hb both in vitro and during intravascular haemolysis, promoting oxidative stress, podocyte dysfunction, and apoptosis. Nrf2 may be a potential therapeutic target to prevent loss of renal function in patients with intravascular haemolysis. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd. 相似文献