全文获取类型
收费全文 | 577篇 |
免费 | 34篇 |
国内免费 | 6篇 |
专业分类
耳鼻咽喉 | 2篇 |
儿科学 | 47篇 |
妇产科学 | 4篇 |
基础医学 | 64篇 |
口腔科学 | 12篇 |
临床医学 | 71篇 |
内科学 | 153篇 |
皮肤病学 | 12篇 |
神经病学 | 20篇 |
特种医学 | 21篇 |
外科学 | 83篇 |
综合类 | 8篇 |
预防医学 | 44篇 |
眼科学 | 3篇 |
药学 | 43篇 |
中国医学 | 1篇 |
肿瘤学 | 29篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 21篇 |
2021年 | 34篇 |
2020年 | 27篇 |
2019年 | 33篇 |
2018年 | 31篇 |
2017年 | 13篇 |
2016年 | 27篇 |
2015年 | 14篇 |
2014年 | 39篇 |
2013年 | 34篇 |
2012年 | 54篇 |
2011年 | 53篇 |
2010年 | 28篇 |
2009年 | 12篇 |
2008年 | 24篇 |
2007年 | 31篇 |
2006年 | 29篇 |
2005年 | 12篇 |
2004年 | 25篇 |
2003年 | 17篇 |
2002年 | 8篇 |
2001年 | 7篇 |
2000年 | 10篇 |
1999年 | 5篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1980年 | 1篇 |
1959年 | 1篇 |
1958年 | 3篇 |
排序方式: 共有617条查询结果,搜索用时 15 毫秒
11.
Muhammad Sohail Afzal Najam Us Sahar Sadaf Zaidi Jean Dubuisson Yves Rouille 《Hepatitis monthly》2014,14(8)
Background:
Hepatitis C Virus (HCV) is a major causative agent for chronic liver disease worldwide. Hepatic steatosis is a frequent histological feature in patients with chronic HCV. Both host and viral factors are involved in steatosis development. It results from uncontrolled growth of cytoplasmic lipid droplets (LDs) in hepatocytes. LDs are intracellular organelles playing key role in the HCV life cycle. HCV core protein localizes at the LD surface and this localization is crucial for virion production.Objectives:
We explored in vitro interplay of core and LDs to investigate the role of core in steatosis.Materials and Methods:
Core expression vectors were transfected in Huh-7 cells. The effect of core protein on LDs content and distribution in the cells was monitored by confocal microscopy. Cells were treated with oleic acid to analyze the effect of increased intracellular LDs on core expression. Core protein expression was monitored by western blot analysis.Results:
Core expression altered the intracellular lipid metabolism, which resulted in a change in LDs morphology. Core LDs interaction was required for this effect since the mutation of two prolines (P138A, P143A), which impair LDs localization, had no impact on LDs morphology. Conversely, oleic acid induced intracellular LD content resulted in increased core expression.Conclusions:
Core-LDs interaction may be an underlying molecular mechanism to induce liver steatosis in patients with HCV infection. This interaction is also crucial for efficient viral replication and persistence in infected cells. Steatosis can also interfere with efficient standard interferon therapy treatment. Management of steatosis should be considered along with standard care for achieving higher sustained virological response (SVR) in patients receiving interferon regimen. 相似文献12.
13.
The presented investigation theoretically studies the physical characteristics of a two-dimensional incompressible hybrid nanofluid in a non-uniform annulus where the boundaries are flexible. A mixed convective peristaltic mechanism is implemented to model blood-based nanofluids using two different nanoparticles (Ag + Al2O3). Convective boundary conditions are employed and different forms of nanoparticles are discussed (bricks, cylinders and platelets). The problem is shortened by engaging a lubrication method. Exact expressions for the temperature of cumulative heat source/sink standards, hemodynamic velocity, pressure gradient and streamlines of different shapes of nanoparticles are obtained. Special cases of pure blood and the Al2O3 nanofluid of our model are derived. A comparison is set between nanofluids and hybrid nanofluids from which we observed variations in heat transfer rate in different regions due to the oscillatory nature of the waves. The current model has the potential to be useful for applications related to the metabolic structures that play a vital role in heat sources inside the human body.The presented investigation theoretically studies the physical characteristics of a two-dimensional incompressible hybrid nanofluid in a non-uniform annulus where the boundaries are flexible. 相似文献
14.
Vahid Khori Ali Mohammad Alizadeh Zohre Gheisary Sadaf Farsinejad Farrokh Najafi Solmaz Khalighfard Fatemeh Ghafari Maryam Hadji Hamid Khodayari 《Lasers in medical science》2016,31(9):1775-1782
Low-level laser therapy (LLLT) is a form of photon therapy which can be a non-invasive therapeutic procedure in cancer therapy using low-intensity light in the range of 450–800 nm. One of the main functional features of laser therapy is the photobiostimulation effects of low-level lasers on various biological systems including altering DNA synthesis and modifying gene expression, and stopping cellular proliferation. This study investigated the effects of LLLT on mice mammary tumor and the expression of Let-7a, miR155, miR21, miR125, and miR376b in the plasma and tumor samples. Sixteen mice were equally divided into four groups including control, and blue, green, and red lasers at wavelengths of 405, 532, and 632 nm, respectively. Weber Medical Applied Laser irradiation was carried out with a low power of 1–3 mW and a series of 10 treatments at three times a week after tumor establishment. Tumor volume was weekly measured by a digital vernier caliper, and qRT-PCR assays were performed to accomplish the study. Depending on the number of groups and the p value of the Kolmogorov-Smirnov test of normality, a t test, a one-way ANOVA, or a non-parametric test was used for data analyses, and p?<?0.05 was considered to be statistically significant. The average tumor volume was significantly less in the treated blue group than the control group on at days 21, 28, and 35 after cancerous cell injection. Our data also showed an increase of Let-7a and miR125a expression and a decrease of miR155, miR21, and miR376b expression after LLLT with the blue laser both the plasma and tumor samples compared to other groups. It seems that the non-invasive nature of laser bio-stimulation can make LLLT an attractive alternative therapeutic tool. 相似文献
15.
Susan Hoe James W. Ivey Mohammed A. Boraey Abouzar Shamsaddini-Shahrbabak Emadeddin Javaheri Sadaf Matinkhoo Warren H. Finlay Reinhard Vehring 《Pharmaceutical research》2014,31(2):449-465
Purpose
A fundamental approach incorporating current theoretical models into aerosol formulation design potentially reduces experimental work for complex formulations. A D-amino acid mixture containing D-Leucine (D-Leu), D-Methionine, D-Tryptophan, and D-Tyrosine was selected as a model formulation for this approach.Methods
Formulation design targets were set, with the aim of producing a highly dispersible D-amino acid aerosol. Particle formation theory and a spray dryer process model were applied with boundary conditions to the design targets, resulting in a priori predictions of particle morphology and necessary spray dryer process parameters. Two formulations containing 60% w/w trehalose, 30% w/w D-Leu, and 10% w/w remaining D-amino acids were manufactured.Results
The design targets were met. The formulations had rugose and hollow particles, caused by deformation of a crystalline D-Leu shell while trehalose remained amorphous, as predicted by particle formation theory. D-Leu acts as a dispersibility enhancer, ensuring that both formulations: 1) delivered over 40% of the loaded dose into the in vitro lung region, and 2) achieved desired values of lung airway surface liquid concentrations based on lung deposition simulations.Conclusions
Theoretical models were applied to successfully achieve complex formulations with design challenges a priori. No further iterations to the design process were required. 相似文献16.
Saima Karim Sweetheart T. Ador-Dionisio Munira Karim Mohammad Karim Sadaf S. Khan Ashish Atreja 《Acute cardiac care》2016,18(1):1-6
Background: Little literature exists on the risk of performing coronary intervention (PCI) on patients who have had recent gastrointestinal bleeding (GIB), although bleeding after PCI has been identified as a risk factor for long-term mortality. Methods: Patients within the Cleveland Clinic PCI database who had acute GIB within 30 days preceding PCI during the same hospitalization (n = 79) were retrospectively compared to those who had PCI without recent GIB (n = 10 979) for mortality and need for revascularization. Baseline characteristics, laboratory values, procedures, morbidities, and mortality were compared using chi-square test for categorical variables and using Wilcoxon rank sum test for continuous variables. Mortality data was obtained using Social Security Death Index and demonstrated using Kaplan–Meier method. Results: The GIB group had more prevalent history of peptic ulcer disease, GIB, gastrointestinal or liver disease (P < 0.0001), transient ischemic accident (P = 0.017), peripheral vascular disease (P = 0.0002), significant carotid artery occlusion (P = 0.023), and myocardial infarction (P < 0.0001). 47% of patients had upper GIB with 20% needing endoscopic intervention. This group had more anemia (P < 0.0001), heart failure (P = 0.0001), cardiogenic shock (10% versus 1.4%, P < 0.001), cardiac arrest (7.6% versus 1%, P < 0.001). GIB group had worse in-hospital mortality (P < 0.0001), long-term mortality (P < 0.001), and a 7.6% re-bleeding incidence. Conclusions: Overall, the patients who had GIB preceding PCI had higher in-hospital mortality and long-term mortality compared with those without GIB before PCI. 相似文献
17.
Five new isostructural lanthanide–organic complexes, [Ln2O2(OH)(HQXD)(H2QXD)2]·H2O (Ln = Eu 1, Tb 2, Sm 3 Dy 4 and Gd 5; H2QXD = quinoxaline-2,3(1H,4H)-dione), have been synthesized under hydrothermal conditions. These complexes are characterized by powder X-ray diffraction (PXRD), infrared spectroscopy (IR), elemental analysis (EA), thermogravimetric-differential thermal analysis (TG-DTA) and photo-luminescent spectroscopy. Single crystal X-ray diffraction analysis of complex 1 revealed that the structure featured in 1D chiral “Eu2O3” chains surrounded by coordinating organic ligands. These chains are interconnected via hydrogen bonding and offset π⋯π stacking interactions of the ligands to form the 3D supramolecular frameworks. The photo-luminescence studies for complexes 1–5 disclosed that the ligand (H2QXD) showed an antenna effect to transfer energy toward the lanthanide cations. The energy transfer mechanism investigations show that the energy transition from the triplet energy level (3ππ*) of ligand H2QXD to the Tb3+ cation is more effective than to the Eu3+, Sm3+ and Dy3+ ions; therefore it has been selected as a representative to examine the potential for sensing small molecules. Complex 2′, which was obtained by the heating treatment of 2 at 150 °C, displayed a high luminescence sensitivity towards small solvent molecules. Tertiary butanol (t-butanol) was found to be an excellent sensitizer, while tetrahydrofuran (THF) was a highly quenching species. Complex 2′ could regain a higher photo-luminescence intensity after treating for 5 cycles with t-butanol, revealing a prospect for reusability.A series of isostructural lanthanide–quinoxaline-2,3(1H,4H)-dione containing 1D chiral chains shows high sensing effect toward the small solvent molecules, in which tertiary butanol was an excellent sensitizer, while tetrahydrofuran was a highly quenching species. 相似文献
18.
19.
Shu Yang Jennifer A. Fifita Kelly L. Williams Sadaf T. Warraich Roger Pamphlett Garth A. Nicholson Ian P. Blair 《Neurobiology of aging》2013
Mutations in PFN1, a gene encoding the actin monomer-binding protein profilin 1, were recently reported in 1% to 2% of familial amyotrophic lateral sclerosis (ALS) patients. In vitro functional studies suggested that PFN1 mutations lead to ubiquitin-positive inclusions and impairment of cytoskeletal pathways. In the present study, mutation analysis of PFN1 was performed in an Australian cohort of 110 ALS families and 715 sporadic ALS patients. No PFN1 mutations were identified in familial ALS patients. Two rare non-synonymous variants (E117D and E117G) were found in sporadic ALS patients at similar incidences to that reported in public SNP databases. Immunostaining of PFN1 in sporadic ALS and familial ALS patients, including those with mutations in SOD1, FUS, UBQLN2 and C9ORF72, found no PFN1-positive inclusions in spinal motor neurons. Our data suggest that PFN1 mutations and pathology are not common in an Australian ALS cohort of predominantly European ancestry. 相似文献
20.