首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   194篇
  免费   17篇
  2023年   3篇
  2022年   2篇
  2021年   11篇
  2020年   5篇
  2019年   6篇
  2018年   4篇
  2017年   3篇
  2016年   6篇
  2015年   9篇
  2014年   5篇
  2013年   8篇
  2012年   11篇
  2011年   16篇
  2010年   16篇
  2009年   9篇
  2008年   12篇
  2007年   21篇
  2006年   6篇
  2005年   13篇
  2004年   4篇
  2003年   10篇
  2002年   2篇
  1998年   3篇
  1997年   1篇
  1996年   2篇
  1995年   2篇
  1994年   5篇
  1993年   1篇
  1992年   3篇
  1991年   2篇
  1990年   1篇
  1988年   1篇
  1982年   1篇
  1977年   1篇
  1976年   1篇
  1970年   1篇
  1969年   1篇
  1968年   2篇
  1956年   1篇
排序方式: 共有211条查询结果,搜索用时 62 毫秒
81.
The renin-angiotensin system is involved in the progression of chronic renal disease of both diabetic and nondiabetic origin. The angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers have been demonstrated to reduce urinary protein excretion and attenuate the development of renal injury. This prospective, randomized, 12-month study assessed the effects of ramipril (N = 23) vs. valsartan (N = 22) vs. combination of ramipril and valsartan (N = 26) on proteinuria, renal function and metabolic profile in 71 patients with nondiabetic proteinuria with normal or slightly impaired renal function. Monotherapy with ramipril or valsartan and combination of these two drugs significantly reduced proteinuria, serum creatinine, cholesterol and triglycerides as well as systolic and diastolic arterial blood pressure. There was no significant difference among three study groups according to reduction of arterial blood pressure, serum cholesterol and triglycerides. At one year, a significant reduction in serum creatinine was recorded in all three study groups, whereas at 3 and 6 months a statistically significant reduction in serum creatinine was only observed in patients on combination therapy. In addition, at 3 months the reduction of proteinuria was significantly greater in patients on combination therapy than in those on either monotherapy. These results indicated the combination therapy with angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers to be more efficacious than either monotherapy in reducing proteinuria and serum creatinine level in the first 3 (proteinuria and serum creatinine) or 6 (serum creatinine) months of treatment.  相似文献   
82.
Objectives This study aims to present the patterns of physical comorbidity in depressed patients and factors strongly associated with depression in a representative sample of Slovenian family practice attendees.Methods Medical data was obtained for 911 general practice attendees. Of them, 221 (24.3%) were diagnosed as depressed. The depressive states of the subjects were evaluated using the Composite International Diagnostic Interview (CIDI). Physical comorbidity was assessed with a questionnaire covering the most common health problems in the Slovenian adult population. Several psycho-social factors were also analysed.Results Those variables significantly related to ICD depression were included in multivariate binary logistic regression analysis, adjusted by age, gender and education. The calculation included the chi-square, odds ratio (OR) with confidence interval (95% CI) and P-value. A P-value < 0.05 was marked as statistically significant.Conclusions There was no significant difference in the number of concurrent chronic diseases in depressed and non-depressed subjects. The risk of depression was increased by the presence of several concomitant factors. The burden of somatic co-morbidity was shown to be smaller than the impact of psychosocial determinants, which also acted as protective factors: the feeling of safety at home and the absence of problems in intimate relationships. The abuse of alcohol and drugs by a family member and current poor financial situation were strongly associated with depression. The impact of concurrent incontinence and chronic bowel disease was also important, though somewhat weaker.  相似文献   
83.
A reverse genetics approach to study feline infectious peritonitis   总被引:1,自引:0,他引:1  
Feline infectious peritonitis (FIP) is a lethal immunopathological disease caused by feline coronaviruses (FCoVs). Here, we describe a reverse genetics approach to study FIP by assessing the pathogenicity of recombinant type I and type II and chimeric type I/type II FCoVs. All recombinant FCoVs established productive infection in cats, and recombinant type II FCoV (strain 79-1146) induced FIP. Virus sequence analyses from FIP-diseased cats revealed that the 3c gene stop codon of strain 79-1146 has changed to restore a full-length open reading frame (ORF).  相似文献   
84.

Background

Bone marrow stromal cell antigen 2 (BST-2) is a cellular factor that restricts the egress of viruses such as human immunodeficiency virus (HIV-1) from the surface of infected cells, preventing infection of new cells. BST-2 is variably expressed in most cell types, and its expression is enhanced by cytokines such as type I interferon alpha (IFN-??). In this present study, we used the beta-retrovirus, mouse mammary tumor virus (MMTV) as a model to examine the role of mouse BST-2 in host infection in vivo.

Results

By using RNA interference, we show that loss of BST-2 enhances MMTV replication in cultured mammary tumor cells and in vivo. In cultured cells, BST-2 inhibits virus accumulation in the culture medium, and co-localizes at the cell surface with virus structural proteins. Furthermore, both scanning electron micrograph (SEM) and transmission electron micrograph (TEM) show that MMTV accumulates on the surface of IFN??-stimulated cells.

Conclusions

Our data provide evidence that BST-2 restricts MMTV release from naturally infected cells and that BST-2 is an antiviral factor in vivo.  相似文献   
85.
There is strong epidemiological evidence that Chlamydia infection can lead to exacerbation of asthma. However, the mechanism(s) whereby chlamydial infection, which normally elicits a strong Th type 1 (Th1) immune response, can exacerbate asthma, a disease characterized by dominant Th type 2 (Th2) immune responses, remains unclear. In the present study, we show that Chlamydia muridarum infection of murine bone marrow-derived dendritic cells (BMDC) modulates the phenotype, cytokine secretion profile, and Ag-presenting capability of these BMDC. Chlamydia-infected BMDC express lower levels of CD80 and increased CD86 compared with noninfected BMDC. When infected with Chlamydia, BMDC secrete increased TNF-alpha, IL-6, IL-10, IL-12, and IL-13. OVA peptide-pulsed infected BMDC induced significant proliferation of transgenic CD4(+) DO11.10 (D10) T cells, strongly inhibited IFN-gamma secretion by D10 cells, and promoted a Th2 phenotype. Intratracheal transfer of infected, but not control noninfected, OVA peptide-pulsed BMDC to naive BALB/c mice, which had been i.v. infused with naive D10 T cells, resulted in increased levels of IL-10 and IL-13 in bronchoalveolar lavage fluid. Recipients of these infected BMDC showed significant increases in airways resistance and decreased airways compliance compared with mice that had received noninfected BMDC, indicative of the development of airways hyperreactivity. Collectively, these data suggest that Chlamydia infection of DCs allows the pathogen to deviate the induced immune response from a protective Th1 to a nonprotective Th2 response that could permit ongoing chronic infection. In the setting of allergic airways inflammation, this infection may then contribute to exacerbation of the asthmatic phenotype.  相似文献   
86.

Background

Non-Hodgkin lymphoma (NHL) is the fifth most common cancer in the U.S. and few causes have been identified. Genetic association studies may help identify environmental risk factors and enhance our understanding of disease mechanisms.

Methodology/Principal Findings

768 coding and haplotype tagging SNPs in 146 genes were examined using Illumina GoldenGate technology in a large population-based case-control study of NHL in the San Francisco Bay Area (1,292 cases 1,375 controls are included here). Statistical analyses were restricted to HIV- participants of white non-Hispanic origin. Genes involved in steroidogenesis, immune function, cell signaling, sunlight exposure, xenobiotic metabolism/oxidative stress, energy balance, and uptake and metabolism of cholesterol, folate and vitamin C were investigated. Sixteen SNPs in eight pathways and nine haplotypes were associated with NHL after correction for multiple testing at the adjusted q<0.10 level. Eight SNPs were tested in an independent case-control study of lymphoma in Germany (494 NHL cases and 494 matched controls). Novel associations with common variants in estrogen receptor 1 (ESR1) and in the vitamin C receptor and matrix metalloproteinase gene families were observed. Four ESR1 SNPs were associated with follicular lymphoma (FL) in the U.S. study, with rs3020314 remaining associated with reduced risk of FL after multiple testing adjustments [odds ratio (OR) = 0.42, 95% confidence interval (CI) = 0.23–0.77) and replication in the German study (OR = 0.24, 95% CI = 0.06–0.94). Several SNPs and haplotypes in the matrix metalloproteinase-3 (MMP3) and MMP9 genes and in the vitamin C receptor genes, solute carrier family 23 member 1 (SLC23A1) and SLC23A2, showed associations with NHL risk.

Conclusions/Significance

Our findings suggest a role for estrogen, vitamin C and matrix metalloproteinases in the pathogenesis of NHL that will require further validation.  相似文献   
87.
88.
89.
In earlier studies, we and others have established that activation of EGFR can promote survival in association with upregulation of Bcl-x(L). However, the mechanism responsible for upregulation of Bcl-x(L) is unknown. For the current studies we have chosen pro-apoptotic, c-Myc-overexpressing murine mammary epithelial cells (MMECs) derived from MMTV-c-Myc transgenic mouse tumors. We now demonstrate that EGFR activation promotes survival through Akt and Erk1/2. Blockade of EGFR kinase activity and the PI3-K/Akt and MEK/Erk pathways with pharmacological inhibitors resulted in a significant induction of cellular apoptosis, paralleled by a downregulation of both Akt and Erk1/2 proteins. Consistent with a survival-promoting role of Akt, we observed that constitutively activated Akt (Myr-Akt) inhibited apoptosis of pro-apoptotic, c-Myc-overexpressing cells following the inhibition of EGFR tyrosine kinase activity. In addressing possible downstream effectors of EGFR through activated Akt, we detected significant upregulation of Bcl-x(L) protein, suggesting this pro-survival protein is a target of Akt in MMECs. By using pharmacological inhibitors of PI3-K/Akt and MEK/Erk together with dominant-negative Akt and Erk1 we observed the decrease in Bcl-x(L) protein. Our findings may be of importance for understanding the emerging role of Bcl-x(L) as a potential marker of poor prognosis in breast cancer.  相似文献   
90.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号