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   148篇
  免费   39篇
  国内免费   1篇
  2024年   1篇
  2023年   5篇
  2022年   8篇
  2021年   9篇
  2020年   4篇
  2019年   13篇
  2018年   6篇
  2017年   9篇
  2016年   8篇
  2015年   6篇
  2014年   17篇
  2013年   13篇
  2012年   8篇
  2011年   14篇
  2010年   10篇
  2009年   9篇
  2008年   7篇
  2007年   3篇
  2006年   4篇
  2005年   2篇
  2004年   3篇
  2003年   3篇
  2001年   2篇
  1999年   4篇
  1998年   3篇
  1996年   2篇
  1995年   2篇
  1994年   1篇
  1993年   2篇
  1992年   3篇
  1991年   3篇
  1990年   1篇
  1988年   1篇
  1986年   1篇
  1980年   1篇
排序方式: 共有188条查询结果,搜索用时 31 毫秒
131.
目的:探讨主动脉夹层(aortic dissection,AD)血管组织中氧化应激蛋白NOX1的表达及意义。方法:收集2014年~2015年在武汉大学人民医院AD患者升主动脉血管组织标本(AD组)及多器官捐献患者升主动脉血管组织标本(对照组)各12例。采用维多利亚蓝染色观察主动脉中膜弹性纤维形态结构;应用SP免疫组织化学法及Western blot法对标本组织中的NOX1进行检测分析。结果:AD组主动脉中膜弹性纤维形态和排列不规则、破碎、丢失,结构紊乱。免疫组织化学显示NOX1阳性表达见于主动脉壁平滑肌细胞胞质中,AD组与对照组比较,NOX1表达明显升高。Western blot蛋白印迹示AD组NOX1表达明显增高,差异有统计学意义(P0.05)。结论:NOX1在AD主动脉中膜中表达上调,可能在AD的发生中发挥作用。  相似文献   
132.
心脏发育是一个复杂的过程.在脊椎动物和无脊椎动物果蝇中驱动早期心脏分化的基因具有惊人的相似性.以果蝇、斑马鱼、小鼠等作为模式动物,以心脏的发育过程为主线,探讨了心脏发育的基因调控的研究进展.  相似文献   
133.
The persistence of Heterorhabditis megidis in soil was studied over a 4-week period. On days 0, 2, 14, and 28, infective juveniles (IJ) were extracted by centrifugal flotation, Baermann funnel, and baiting of soil with Tenebrio molitor larvae, which were then dissected. Extraction efficiencies on day 0 were 82% by centrifugal flotation, 56% by Baermann funnel, and 19.8% by bait insect. The relative efficiency of the three methods changed over time. The relationship between the density of nematodes in the soil and the proportion recovered by dissection was non-linear. Up to a dose of approximately 60 IJ/insect, less than 12% became established, while at higher doses (up to 200 IJ/insect) the invasion efficiency was 23%. Mortality of bait insects increased from day 0 to day 2, but decreased to day 28. A novel method of assessing soil pathogenicity by preparing a soil density series and calculating the dose of soil or IJ that kills 50% of the bait insects gave a similar pattern. This method is recommended as a means of tracking changes in pathogenicity over time when bait insect mortality in undiluted soil is at or near 100%. Two methods of preparing a series of Heterorhabditis IJ densities in soil, either by diluting the soil itself with IJ-free soil or by adding diluted suspensions of IJ to the soil, resulted in the same bait insect mortalities.  相似文献   
134.
杨潜  苏东玮  施俊义  盛湲 《生物磁学》2009,(16):3081-3085
研究背景:乳腺癌是女性常见的恶性肿瘤之一,同时也是治愈率最高的癌症,文献报道早期乳腺癌术后5年生存率达85.16%。上肢淋巴水肿是腋窝淋巴结清扫术后常见并发症,术后10—35%患者出现上肢水肿,就上肢淋巴水肿的风险因素,国内外做了许多研究,但结果不一,分歧较大。方法:抽取60例腋窝淋巴结清扫术后患者,调查统计可能与腋窝淋巴结清扫术后上肢淋巴水肿相关的8个因素(变量):年龄、临床分期、是否放疗、是否出现延迟愈合/感染/积液等术后其它并发症、术后上肢功能锻炼、是否是优势侧,平时是否参加体育锻炼,是否有高血压等合并症。数据采用SPSS13.0分析软件以logistic回归方法进行分析。结果:四项关联因素分别为:1、是否放疗(OR=8.966)2、延迟愈合/感染/积液等其它术后并发症(0R=8.493)3、术后上肢功能锻炼(OR=0.194)4、高血压(0R=5.609)。结论:放疗、其它术后并发症、高血压为腋窝淋巴结清扫术后上肢淋巴水肿的风险因素,而术后上肢功能锻炼为术后水肿的保护因素。  相似文献   
135.
136.
BackgroundThe purpose of this study was to investigate the dose coverage of sentinel lymph nodes (SLN), level I, II and III axillary volumes from tangent fields for breast cancer patients with positive SLN without axillary dissection.Materials and methodsIn 30 patients with cN0 invasive breast cancer treated with breast conserving surgery and SLN biopsy, the SLN area was intraoperatively marked with a titanium clip. Retrospectively, the SLN area and axillary target volumes were contoured, and three plans [standard tangent fields (STgF), high tangent fields (HTgF), and STgF + axillary-supraclavicular field] were generated for each patient. The prescribed dose was standardized to 50 Gy in 2 Gy fractions to the isocenter.ResultsThe mean dose with STgF or HTgF was 33.1 and 49.1 Gy (p = 0.0001) in the SLN area, 25.7 and 45.1 Gy (p < 0.0001) in the volume of level I, 7.2 and 28.9 Gy (p < 0.0001) in the level II and 3.5 and 12.7 Gy (p = 0.0003) in the level III. Adequate therapeutic doses to the level II or III volumes were delivered only with STgF + axillary-supraclavicular field. The mean dose of ipsilateral lung was the highest with the three-field-technique, 9.9 Gy. SLN area, level I, II or III were completely included in the HTgF with 93.3%, 73.3%, 13.3% and 0%, respectively.ConclusionsSLN area should be marked by surgical clip and axillary target volumes should be contoured to obtain accurate dose estimations. The use of HTgF improve axillary coverage.  相似文献   
137.
The risk of acute aortic dissection (AAD) exhibits chronobiological variations with peak onset in the morning and in winter. However, it is not known whether the time of day or season of the year of the AAD affects clinical outcomes. We studied 1,032 patients enrolled in the International Registry of Acute Aortic Dissection from January 1997 to December 2001. For circadian and seasonal analysis, the time and date of symptom onset were available for 741 and 1,007 patients, respectively, and were grouped into four 6 h periods (morning, afternoon, evening, and night) and four seasons (winter, spring, summer, and autumn). The χ2 test for goodness of fit was used to evaluate non‐uniformity of the time of day and time of year for critical in‐hospital clinical events, including death. While highest incidence of AAD occurred in the morning and winter, clinical events (including mortality) were similar during the four different periods of the 24 h (χ2=1.9, p=0.60) and seasonal (χ2=1.2, p=0.75) periods.  相似文献   
138.
Migraine and its transformation to chronic migraine are healthcare burdens in need of improved treatment options. We seek to define how neural immune signaling modulates the susceptibility to migraine, modeled in vitro using spreading depression (SD), as a means to develop novel therapeutic targets for episodic and chronic migraine. SD is the likely cause of migraine aura and migraine pain. It is a paroxysmal loss of neuronal function triggered by initially increased neuronal activity, which slowly propagates within susceptible brain regions. Normal brain function is exquisitely sensitive to, and relies on, coincident low-level immune signaling. Thus, neural immune signaling likely affects electrical activity of SD, and therefore migraine. Pain perception studies of SD in whole animals are fraught with difficulties, but whole animals are well suited to examine systems biology aspects of migraine since SD activates trigeminal nociceptive pathways. However, whole animal studies alone cannot be used to decipher the cellular and neural circuit mechanisms of SD. Instead, in vitro preparations where environmental conditions can be controlled are necessary. Here, it is important to recognize limitations of acute slices and distinct advantages of hippocampal slice cultures. Acute brain slices cannot reveal subtle changes in immune signaling since preparing the slices alone triggers: pro-inflammatory changes that last days, epileptiform behavior due to high levels of oxygen tension needed to vitalize the slices, and irreversible cell injury at anoxic slice centers. In contrast, we examine immune signaling in mature hippocampal slice cultures since the cultures closely parallel their in vivo counterpart with mature trisynaptic function; show quiescent astrocytes, microglia, and cytokine levels; and SD is easily induced in an unanesthetized preparation. Furthermore, the slices are long-lived and SD can be induced on consecutive days without injury, making this preparation the sole means to-date capable of modeling the neuroimmune consequences of chronic SD, and thus perhaps chronic migraine. We use electrophysiological techniques and non-invasive imaging to measure neuronal cell and circuit functions coincident with SD. Neural immune gene expression variables are measured with qPCR screening, qPCR arrays, and, importantly, use of cDNA preamplification for detection of ultra-low level targets such as interferon-gamma using whole, regional, or specific cell enhanced (via laser dissection microscopy) sampling. Cytokine cascade signaling is further assessed with multiplexed phosphoprotein related targets with gene expression and phosphoprotein changes confirmed via cell-specific immunostaining. Pharmacological and siRNA strategies are used to mimic and modulate SD immune signaling.  相似文献   
139.
ABSTRACT

This study explored the periodic changes in the onset of aortic dissection in a single center in northern China, with the goal to improve predictability and prevention. We collected the clinical data of 1121 patients from Hebei Province treated for acute aortic dissection at Fuwai Hospital between January 2010 and December 2016. The patterns of aortic dissection during different periods of each day, each month, and each quarter of a year were analyzed. Variations in the number of cases were summarized for weekdays, weekends, and different periods of a day in each season. We compared the differences in gender, age, body mass index, Marfan syndrome, hypertension, and the type of aortic dissection during different time periods and different seasons. In the study, 774 patients (69.1%) with type A aortic dissection and 347 patients (30.9%) with type B aortic dissection were included. The average age of 1121 patients was 51.4 ± 12.0 years. Overall, the peak period for the onset of aortic dissection in a day was between 13:00 and 18:00. There was no statistically significant difference in the number of cases between weekdays and weekend (P = 0.94). Most cases occurred in winter (30.9%); the rate of onset was the lowest in summer (16.6%). No statistically significant difference was observed between male and female patients in terms of variations during different periods of a day (P = 0.45) and seasons (P = 0.12). In conclusion, aortic dissection displayed circadian and seasonal patterns in northern China. Onset of the disease peaked between 13:00 and 18:00 in a day. Winter was the peak season for the onset of acute aortic dissection, regardless of sex, type of dissection and age.  相似文献   
140.
BackgroundBreast cancer patients with positive sentinel lymph node biopsy (SLNB) may be spared axillary lymph node dissection (ALND) in favour of irradiation. The aim of the study was to estimate local control probability in the axilla (axLCP).Materials and methodsWe identified 1832 invasive breast cancer patients who had undergone SLNB at our centre. We measured maximal metastasis diameter (SLDmax) in the sentinel lymph nodes and lymph node metastasis volume (VALN) from ALND in 246 patients with one or two positive SLNs. We calculated axLCP after irradiation and systemic treatment for different molecular types.ResultsVALN values are higher for high grade tumours and larger metastases in SLNs (> 5 mm). It is smaller in luminal A tumours. axLCP is high, nearly 100%, in all molecular types in radiation sensitive tumours (SF2 Gy = 0.45), except luminal B. Expected axLCP is relatively low (67%) in luminal B radiation sensitive tumours with no chemotherapy and nearly 100% with chemotherapy.ConclusionVALN values differ among molecular tumour types. They depend on SLNDmax and tumour grade. New prognostic factors are needed for selected luminal B breast cancer patients (i.e. high grade tumours, large metastases in SLNs) after positive SLNB intended to be spared ALND and chemotherapy.  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