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   131篇
  免费   7篇
  国内免费   3篇
耳鼻咽喉   1篇
儿科学   1篇
基础医学   23篇
口腔科学   3篇
临床医学   3篇
内科学   9篇
皮肤病学   2篇
神经病学   9篇
外科学   1篇
综合类   5篇
预防医学   29篇
眼科学   22篇
药学   30篇
中国医学   2篇
肿瘤学   1篇
  2023年   2篇
  2021年   5篇
  2020年   4篇
  2019年   11篇
  2018年   7篇
  2017年   5篇
  2016年   2篇
  2015年   5篇
  2014年   10篇
  2013年   12篇
  2012年   8篇
  2011年   11篇
  2010年   9篇
  2009年   9篇
  2008年   8篇
  2007年   5篇
  2006年   4篇
  2005年   10篇
  2004年   1篇
  2003年   2篇
  2002年   3篇
  2001年   1篇
  2000年   3篇
  1999年   3篇
  1998年   1篇
排序方式: 共有141条查询结果,搜索用时 15 毫秒
1.
The OPA1 gene, encoding a dynamin-related GTPase that plays a role in mitochondrial biogenesis, is implicated in most cases of autosomal dominant optic atrophy (ADOA). Sixty-nine pathogenic OPA1 mutations have been reported so far. Most of these are truncating mutations located in the GTPase domain coding region (exons 8-16) and at the 3'-end (exons 27-28). We screened 44 patients with typical ADOA using PCR-sequencing. We also tested 20 sporadic cases of bilateral optic atrophy compatible with ADOA. Of the 18 OPA1 mutations found, 14 have never been previously reported. The novel mutations include one nonsense mutation, 3 missense mutations, 6 deletions, one insertion and 3 exon-skipping mutations. Two of these are de novo mutations, which were found in 2 patients with sporadic optic atrophy. The recurrent c.2708_2711delTTAG mutation was found in 2 patients with a severe congenital presentation of the disease. These results suggest that screening for OPA1 gene mutations may be useful for patients with optic atrophy who have no affected relatives, or when the presentation of the disease is atypical as in the case of early onset optic atrophy.  相似文献   
2.
《Journal of neurogenetics》2013,27(2):151-157
Abstract: This is the second of two reviews that include some of the studies we, members of the Pak laboratory and collaborators, did from 2000 to 2010 on the mutants that affect synaptic transmission in the Drosophila visual system. Of the five mutants we discuss, two turned out to also play roles in the larval neuromuscular junction. This review complements the one on phototransduction to give a fairly complete account of what we focused on during the 10-year period, although we also did some studies on photoreceptor degeneration in the early part of the decade. Besides showing the power of using a genetic approach to the study of synaptic transmission, the review contains some unexpected results that illustrate the serendipitous nature of research.  相似文献   
3.
目的:右室心尖(RVA)起搏可导致心室重构及心力衰竭。本研究探讨RVA起搏是否引起心力衰竭相关的基因表达水平的变化。 方法:选取80例因三度房室传导阻滞行永久起搏器植入术的心功能正常患者,随机1:1分为右室心尖起搏组和右室间隔部(RVS)起搏组,术前抽取外周血,测定心肌肌浆网Ca2+-ATP酶(SERCA)和 视神经萎缩症蛋白(OPAl)的mRNA表达水平,测定NT-proBNP,行超声心动图检查。术后1、6及12个月进行常规起搏器随访,并测定SERCA和 OPAl的mRNA表达水平,测定NT-proBNP,行超声心动图检查。 结果:与术前比较,RVA起搏组术后1月,6月及12月SERCA和OPA1 mRNA表达水平明显下降(P均<0.05),起搏器植入术后12月,RVA和RVS组间SERCA、OPA1 mRNA表达水平差异有统计学意义(P=0.028;P=0.034)。RVA起搏组术后12月与术前比较,LVEF值下降有统计学差异(P=0.012),而RVS起搏组LVEF值下降无统计学差异(P>0.05)。与术前比较,RVA起搏组术后12月的SERCA 和OPA1 mRNA表达水平变化与LVEF值变化呈正相关(r=0.529,95% CI:0.113-0.287, P=0.017;r=0.495,95%CI:0.028-0.788,P=0.044)。RVA起搏术后12月心功能减低组的SERCA、OPAl的mRNA表达水平较无心功能减低组明显下降,差异有统计学意义(P=0.022;P=0.035)。 结论:RVA起搏术后外周血SERCA、OPAl的mRNA表达水平发生变化,这种基因表达水平的变化先于心脏结构及功能改变,而且可能与心功能减低相关。  相似文献   
4.
A 39-year-old healthy woman presented for decreased vision at distance and near for 4 years. She also noted a decrease in her color vision. Her best-corrected visual acuities were 20/70 in each eye. Her visual fields were abnormal, and she had bilateral sluggish pupils, impaired color vision, and optic disc pallor. The magnetic resonance imaging of the brain, heavy metal screen, autoimmune work-up, B12, B6, folate, erythrocyte sedimentation rate, rapid plasma reagin, and Lyme titer were all normal. Optical coherence tomography of the macula and electroretinogram were normal; the visual evoked potential was unrecordable in both eyes. She denied a family history of similar ocular issues, and genotyping of the OPA1 gene revealed a novel previously unreported mutation at IVS12+10T >C.  相似文献   
5.
《Vaccine》2015,33(39):5031-5034
Aluminum (Al) components in vaccines are known to act as adsorbents that interfere with accurate protein quantification by the Lowry method. Therefore, certain modifications based on the characteristics and compositions of the vaccine are required for determination of protein contents.We investigated the effects of an additional centrifugal separation and found that protein contents were overestimated by up to 238% without centrifugation through a collaborative study performed with hepatitis B vaccines containing Al. However, addition of a centrifugation step yielded protein concentrations that were similar to the actual values, with small coefficients of variation (CVs). Proficiency testing performed in 11 laboratories showed that four laboratories did not have satisfactory results for vaccines containing aluminum hydroxide, although all laboratories were proficient in protein analysis when samples did not contain aluminum hydroxide. Incomplete resuspension of aluminum hydroxide solution with alkaline copper solution was the major cause of insufficient proficiency in these laboratories.  相似文献   
6.
《Vaccine》2018,36(5):698-706
BackgroundTo support vaccination programs in developing countries, a 4-dose vial presentation of pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) was developed. This study assessed immunologic non-inferiority and safety of the investigational PHiD-CV 4-dose versus licensed 1-dose vial presentation in infants.MethodsIn this phase III, mono-center, observer-blind study in Bangladesh, 6–10-week-old infants were randomized 1:1 to receive PHiD-CV primary vaccination (at ages 6, 10, 18 weeks) and a booster dose (at age 9 months) with a 4-dose vial (with preservative, 4DV group) or 1-dose vial (preservative-free, 1DV group). DTPw-HBV/Hib was (co)-administered per study protocol and polio, measles and rubella vaccines as part of the national immunization program. Non-inferiority of PHiD-CV 4-dose versus 1-dose vial for each vaccine pneumococcal serotype (VT) and vaccine-related serotype 19A in terms of antibody geometric mean concentration (GMC) was assessed (criterion: upper limit of 2-sided 95% confidence interval of antibody GMC ratios [1DV/4DV] <2-fold). Immune responses were measured. Solicited, unsolicited and serious adverse events (AEs) were evaluated.ResultsOf 320 infants (160 per group) vaccinated during the primary vaccination phase, 297 received a booster. Non-inferiority was demonstrated for each VT and 19A. One month post-primary vaccination, for most VT, ≥97.9% of infants in each group had antibody concentrations ≥0.2 μg/mL; for 19A ≥ 80.1% reached this threshold. Pneumococcal antibody responses and opsonophagocytic activity for each VT and 19A were within similar ranges between groups after primary and booster vaccination, as were anti-protein D responses. Booster immune responses were observed in both groups. Reported AEs were within similar ranges for both presentations.ConclusionImmunologic non-inferiority of PHiD-CV 4-dose vial (with preservative) versus PHiD-CV 1-dose vial (preservative-free) was demonstrated. Immune responses and reactogenicity following primary/booster vaccination were within similar ranges for both presentations. PHiD-CV 4-dose vial would help improve access and coverage in resource-limited countries.Clinical Trial Registry: NCT02447432.  相似文献   
7.
Mitochondria are the hub for energy production within living cells. They can undergo morphological changes in response to nutrient availability and cellular stress. Here, we review how exercise chronically and acutely affects mitochondrial dynamics. Moreover, we discuss whether mitochondrial dysfunction observed in elderly subjects is due to the ageing process per se or due to the associated sedentary state. Finally, we study how endurance exercise can improve mitochondrial dynamics in older subjects, thereby improving their overall health and likely limiting muscle waste.  相似文献   
8.
Flow cytometry, singlet platelet counting, and optical aggregation have been used to monitor clopidogrel and glycoprotein IIb/IIIa (GPIIb/IIIa) platelet antagonists. Optical aggregation is considered the gold standard, but neither it nor flow cytometry is convenient in larger-scale clinical studies or point-of-care systems. Singlet platelet counting, a point-of-care assay correlated with optical platelet aggregation, only provides a measurement of platelet function at a single point in time. The Thrombelastograph is used to assay whole blood for thrombin-generated maximal clot-shear elasticity, referred to as the maximal amplitude (MA). Although platelet dysfunction, thrombocytopenia, and the in vitro effect of strong inhibitors such as IIb/IIIa antagonists can be observed, with thrombin generation milder platelet inhibitors cannot be assessed. We modified the Thromboelastograph assay, using reptilase and factor XIIIa, to form a clot, without thrombin generation, in heparinized whole blood. The resulting clot MA is dependent on added platelet agonists such as ADP or arachidonic acid, is sensitive to platelet antagonists, and provides a continuous measure of platelet function more analogous and better correlated with optical aggregation. This novel modification of the Thromboelastograph assay should prove to be a useful point-of-care whole-blood assay with which to monitor the effects of GPIIb/IIIa, ADP, and thromboxane A(2)-receptor-inhibiting drugs in patients.  相似文献   
9.
Validation of fumonisin biomarkers in F344 rats   总被引:1,自引:0,他引:1  
Fumonisins (FNs) are ubiquitous contaminants of cereal grains. Fumonisin B(1) (FB(1)) was linked to several animal and human diseases. To validate FB(1) biomarkers for studying human disease risks, F344 rats were administered by gavage with either a single dose of 0, 10 or 25 mg FB(1)/kg body weight (BW) or repeated doses of 0, 1.0, or 2.5 mg FB(1)/kg BW/day for 5 weeks. FB(1) excretion and FB(1)-induced metabolic alterations of sphingolipids in rat urine, feces and serum were assessed. Dose-dependent urinary and fecal excretion of free FB(1) were found in both single-dose- and repeat-dose-treated rats. In the single-dose study, urinary sphinganine (Sa) to sphingosine (So) ratio (Sa/So) reached a maximum at day 7 for the high-dose group and at day 5 for the low-dose group, whereas serum Sa/So showed only marginal changes. In the repeat-dose study, urinary Sa/So was persistently elevated at 2 weeks, while serum Sa/So was unchanged. Time course changes of sphinganine 1-phosphate (SaP) and sphingosine 1-phosphate (SoP) were also examined. Although serum Sa/So and SaP/SoP ratios showed no signs of time- or dose-dependent changes, a 10-fold increase in urinary SaP/SoP was observed, suggesting that urinary SaP/SoP is a more sensitive biomarker for FB(1) exposure. The accumulation of SaP and SoP was evident in the time course of SaP/Sa and SoP/So, which may reflect activity changes of enzymes closely related to the metabolism and catabolism of SaP and SoP. These results provide concrete evidence towards the practical use of excreted FB(1), Sa/So and SaP/SoP as biomarkers of exposure to FNs.  相似文献   
10.
目的:探讨缺氧-复氧(hypoxia/reoxygenation,H/R)后人近曲肾小管上皮细胞(HK-2)内动力相关蛋白1(Dynamin related protein 1,DRP1)及视神经萎缩症蛋白1(optic atrophy,OPA1)表达的变化。方法:以人近曲肾小管上皮细胞株为研究对象,将培养细胞随机分为正常对照组和H/R组。正常对照组常规培养,H/R组先缺氧24h,然后复氧培养6h。光镜观察细胞形态变化,CCK-8检测细胞活力,透射电子显微镜观察线粒体形态改变,免疫组织化学法检测细胞内DRP1和OPA1蛋白表达。结果:H/R组与对照组相比,细胞活力下降,线粒体出现凋亡相关改变,OPA1表达减少而DRP1的表达增加。结论:缺氧-复氧可导致HK-2细胞发生凋亡相关改变,其机制可能与诱导线粒体形态相关蛋白DRP1、OPA1的表达改变相关。  相似文献   
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