全文获取类型
收费全文 | 375篇 |
免费 | 11篇 |
国内免费 | 15篇 |
专业分类
401篇 |
出版年
2022年 | 5篇 |
2021年 | 12篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 10篇 |
2015年 | 26篇 |
2014年 | 15篇 |
2013年 | 23篇 |
2012年 | 46篇 |
2011年 | 53篇 |
2010年 | 28篇 |
2009年 | 8篇 |
2008年 | 9篇 |
2007年 | 10篇 |
2006年 | 5篇 |
2005年 | 35篇 |
2004年 | 21篇 |
2003年 | 13篇 |
2002年 | 15篇 |
2001年 | 17篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 8篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1978年 | 2篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1943年 | 1篇 |
排序方式: 共有401条查询结果,搜索用时 12 毫秒
121.
Baligh R. Yehia Ramin S. Herati John A. Fleishman Joel E. Gallant Allison L. Agwu Stephen A. Berry P. Todd Korthuis Richard D. Moore Joshua P. Metlay Kelly A. Gebo for the HIV Research Network 《PloS one》2014,9(7)
Objectives
Guidelines recommend hepatitis C virus (HCV) screening for all people living with HIV (PLWH). Understanding HCV testing practices may improve compliance with guidelines and can help identify areas for future intervention.Methods
We evaluated HCV screening and unnecessary repeat HCV testing in 8,590 PLWH initiating care at 12 U.S. HIV clinics between 2006 and 2010, with follow-up through 2011. Multivariable logistic regression examined the association between patient factors and the outcomes: HCV screening (≥1 HCV antibody tests during the study period) and unnecessary repeat HCV testing (≥1 HCV antibody tests in patients with a prior positive test result).Results
Overall, 82% of patients were screened for HCV, 18% of those screened were HCV antibody-positive, and 40% of HCV antibody-positive patients had unnecessary repeat HCV testing. The likelihood of being screened for HCV increased as the number of outpatient visits rose (adjusted odds ratio 1.02, 95% confidence interval 1.01–1.03). Compared to men who have sex with men (MSM), patients with injection drug use (IDU) were less likely to be screened for HCV (0.63, 0.52–0.78); while individuals with Medicaid were more likely to be screened than those with private insurance (1.30, 1.04–1.62). Patients with heterosexual (1.78, 1.20–2.65) and IDU (1.58, 1.06–2.34) risk compared to MSM, and those with higher numbers of outpatient (1.03, 1.01–1.04) and inpatient (1.09, 1.01–1.19) visits were at greatest risk of unnecessary HCV testing.Conclusions
Additional efforts to improve compliance with HCV testing guidelines are needed. Leveraging health information technology may increase HCV screening and reduce unnecessary testing. 相似文献122.
123.
124.
De Rosa FG Garazzino S Audagnotto S Bargiacchi O Zeme DA Gramoni A Barberis B Ranieri VM Di Perri G;Piedmont Intensive Care Unit Network 《The new microbiologica》2008,31(1):81-87
This study reports the results of a one-day point prevalence study of infections performed in 2001 (SPIR01) and 2002 (SPIR02) in a Regional network of ICUs in Piedmont, Italy. The study aims were to illustrate the overall proportion of infected patients and the rate of ICU-acquired infections. Mortality rate was evaluated three weeks after the study days. Resistance pattern of Staphylococcus aureus, coagulase negative Staphylococci and Pseudomonas aeruginosa were recorded. The primary end-point of the study was to document the prevalence and associated risk factors of the ICU-acquired infections, and the impact of infections on mortality. The prevalence of ICU-acquired infection was 30% in SPIR01, and 38.3% in SPIR02. The rate of methicillin-resistance was high among isolates of Staphylococcus aureus and coagulase-negative Staphylococci. The prevalence of ICU-acquired infections was lower than that reported in the EPIC study. In our experience, this Regional survey stimulated further research and collaboration to improve the prophylaxis, diagnosis and treatment of ICU-acquired infections. 相似文献
125.
126.
Directional migration of leukocytes: their pathological roles in inflammation and strategies for development of anti-inflammatory therapies 总被引:1,自引:0,他引:1
GENG JIAN Guo Institute of Biochemistry Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Yue Yang Road Shanghai China 《Cell research》2001,(2)
INTRODUCTIONDireCtional cell migratioll is a basic feature ofmany cell types in a vaxiety of species. It has beenknown for centuries. For example, migration of immunological cells has been described in the 1800s[1].Since then, the biological importance of directionalcell migrations has been recognized and emphasized.It participates in varinus aspects of biological development, such as fertilization, embryogenesis, patterning, tissue and organ formation. It also involvesin vaxious physiol… 相似文献
127.
on Behalf of the NCI Breast Prostate Cancer Cohort Consortium 《Free radical research》2013,47(3):380-386
AbstractBoth endogenous factors (genomic variations) and exogenous factors (environmental exposures, lifestyle) impact the balance of reactive oxygen species (ROS). Variants of the ND3 (rs2853826; G10398A) gene of the mitochondrial genome, manganese superoxide dismutase (MnSOD; rs4880 Val16Ala) and glutathione peroxidase (GPX-1; rs1050450 Pro198Leu), are purported to have functional effects on regulation of ROS balance. In this study, we examined associations of breast and prostate cancer risks and survival with these variants, and interactions between rs4880–rs1050450, and alcohol consumption—rs2853826. Nested case-control studies were conducted in the Breast and Prostate Cancer Cohort Consortium (BPC3), consisting of nine cohorts. The analyses included over 10726 post-menopausal breast and 7532 prostate cancer cases with matched controls. Logistic regression models were used to evaluate associations with risk, and proportional hazard models were used for survival outcomes. We did not observe significant interactions between polymorphisms in MnSOD and GPX-1, or between mitochondrial polymorphisms and alcohol intake and risk of either breast (p-interaction of 0.34 and 0.98, respectively) or prostate cancer (p-interaction of 0.49 and 0.50, respectively). We observed a weak inverse association between prostate cancer risk and GPX-1 Leu198Leu carriers (OR 0.87, 95% CI 0.79–0.97, p = 0.01). Overall survival among women with breast cancer was inversely associated with G10398 carriers who consumed alcohol (HR 0.66 95% CI 0.49–0.88). Given the high power in our study, it is unlikely that interactions tested have more than moderate effects on breast or prostate cancer risk. Observed associations need both further epidemiological and biological confirmation. 相似文献
128.
Donhauser N Pritschet K Helm M Harrer T Schuster P Ries M Bischof G Vollmer J Smola S Schmidt B;German Competence Network HIV/AIDS 《PloS one》2012,7(3):e33925
Although a signature of increased interferon (IFN-)alpha production is observed in HIV-1 infection, the response of circulating plasmacytoid dendritic cells (PDC) to Toll-like receptor ligand stimulation is substantially impaired. This functional PDC deficit, which we specifically observed in HIV-1 infected individuals with less than 500 CD4+ T cells/µl, is not well understood. We provide evidence that the peripheral IFN-alpha production in HIV-1 infection is actively suppressed by the enhanced interaction of CD40 ligand (CD40L), a member of the tumor necrosis factor family, and its receptor CD40, which are both upregulated upon immune activation. Plasma levels of soluble CD40L were significantly higher in untreated HIV-1 infected individuals (n = 52) than in subjects on long-term antiretroviral therapy (n = 62, p<0.03) and in uninfected control donors (n = 16, p<0.001). Concomitantly, cell-associated CD40L and the expression of the receptor CD40 on the PDC were significantly upregulated in HIV-1 infection (p<0.05). Soluble and cell-associated CD40L inhibited the PDC-derived IFN-alpha production by CpG oligodeoxynucleotides dose-dependently. This suppressive effect was observed at much lower, physiological CD40L concentrations in peripheral blood mononuclear cells (PBMC) of HIV-1 infected individuals compared to controls (p<0.05). The CpG-induced IFN-alpha production in PBMC of HIV-1 infected donors was directly correlated with PDC and CD4+ T cell counts, and inversely correlated with the viral loads (p<0.001). In HIV-1 infected donors with less than 500 CD4+ T cells/µl, the CpG-induced IFN-alpha production was significantly correlated with the percentage of CD40-expressing PDC and the level of CD40 expression on these cells (p<0.05), whereas CD40L plasma levels played a minor role. In addition, low-dose CD40L contributed to the enhanced production of interleukin 6 and 8 in PBMC of HIV-1 infected donors compared to controls. Our data support the conclusion that the chronic immune activation in HIV-1 infection impairs peripheral PDC innate immune responses at least in part via enhanced CD40:CD40L interactions. 相似文献
129.
XI CHEN WEI ZHANG YUN FEI GAO XIAO QIN SU ZHONG HE ZHAI * College of Life Sciences Peking University Beijing China The Key Laboratory of Cell Proliferation Regulation Biology of the Ministry of Education College of Life Sciences 《Cell research》2002,(Z1)
P21Waf1/Cip1 is a potent cyclin-dependent kinase inhibitor. As a downstream mediator of p53, p21Waf1/Cip1 involves in cell cycle arrest, differentiation and apoptosis. Previous studies in human cells provided evidence for a link between p21Waf1/Cip1 and cellular senescence. While in murine cells, the role of p21Waf1/Cip1 is indefinite. We explored this issue using NIH3T3 cells with inducible p21Waf1/Cip1 expression. Induction of p21Waf1/Cip1 triggered G1 growth arrest, and NIH3T3-p21 cells exhibited morphologic features, such as enlarged and flattened cellular shape, specific to the senescence phenotype. We also showed that p21Waf1/Cip1-transduced NIH3T3 cells expressed β-galactosidase activity at pH 6.0, which is known to be a marker of senescence. Our results suggest that p21Waf1/Cip1 can also induce senescence-like changes in murine cells. 相似文献
130.
Desir Casares-Marfil Martin Kerick Eduardo Andrs-Len Pau Bosch-Nicolau Israel Molina Chagas Genetics CYTED Network Javier Martin Marialbert Acosta-Herrera 《PLoS neglected tropical diseases》2021,15(10)
A recent genome-wide association study (GWAS) identified a locus in chromosome 11 associated with the chronic cardiac form of Chagas disease. Here we aimed to elucidate the potential functional mechanism underlying this genetic association by analyzing the correlation among single nucleotide polymorphisms (SNPs) and DNA methylation (DNAm) levels as cis methylation quantitative trait loci (cis-mQTL) within this region. A total of 2,611 SNPs were tested against 2,647 DNAm sites, in a subset of 37 chronic Chagas cardiomyopathy patients and 20 asymptomatic individuals from the GWAS. We identified 6,958 significant cis-mQTLs (False Discovery Rate [FDR]<0.05) at 1 Mb each side of the GWAS leading variant, where six of them potentially modulate the expression of the SAC3D1 gene, the reported gene in the previous GWAS. In addition, a total of 268 cis-mQTLs showed differential methylation between chronic Chagas cardiomyopathy patients and asymptomatic individuals. The most significant cis-mQTLs mapped in the gene bodies of POLA2 (FDR = 1.04x10-11), PLAAT3 (FDR = 7.22x10-03), and CCDC88B (FDR = 1.89x10-02) that have been associated with cardiovascular and hematological traits in previous studies. One of the most relevant interactions correlated with hypermethylation of CCDC88B. This gene is involved in the inflammatory response, and its methylation and expression levels have been previously reported in Chagas cardiomyopathy. Our findings support the functional relevance of the previously associated genomic region, highlighting the regulation of novel genes that could play a role in the chronic cardiac form of the disease. 相似文献