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   138篇
  免费   32篇
  国内免费   13篇
  2023年   1篇
  2022年   4篇
  2021年   3篇
  2020年   6篇
  2019年   20篇
  2018年   16篇
  2017年   7篇
  2016年   5篇
  2015年   4篇
  2014年   9篇
  2013年   6篇
  2012年   7篇
  2011年   7篇
  2010年   5篇
  2009年   6篇
  2008年   2篇
  2007年   6篇
  2006年   2篇
  2005年   5篇
  2004年   6篇
  2003年   3篇
  2002年   5篇
  2001年   4篇
  2000年   4篇
  1999年   6篇
  1998年   3篇
  1997年   2篇
  1996年   1篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   3篇
  1990年   1篇
  1988年   4篇
  1987年   1篇
  1985年   1篇
  1984年   5篇
  1981年   2篇
  1980年   2篇
  1974年   1篇
  1972年   1篇
  1971年   1篇
排序方式: 共有183条查询结果,搜索用时 15 毫秒
61.
目的:分析糖尿病肾病(Diabetic Nephropthy,DN)患者血清脂肪特异性丝氨酸蛋白酶抑制剂(Vaspin)水平的变化及其与炎症因子的关系。方法:将我院近期(2016年10月-2019年10月)收治100例DN患者设置为DN组,依据DN临床进展分期分组,39例白蛋白尿正常者设置为A组、40例早期DN微量蛋白尿者设置为B组、21例临床DN大量蛋白尿者设为C组,并选取同期于我院的健康体检健康者50例设置为健康组。检测和比价各组糖脂代谢水平、血清Vaspin、炎性因子水平,并进行相关性分析。结果:四组入组者脂代谢各项指标水平相比差异无统计学意义(P0.05)。而DN组中A组、B组、C组患者血清糖代谢水平均明显高于健康组(P0.05)。DN组各组Vaspin、TNF-α、IL-6、MCP-1水平均高于健康组(P0.05)。C组、B组、A组IL-6、TNF-α、MCP-1升高,Vaspin降低(P0.05)。A组IL-10水平高于健康组(P0.05)。其余各组间比较(P0.05)。各组Vaspin水平与促炎因子IL-6、TNF-α、MCP-1水平呈负相关(P0.05),与抗炎因子IL-10水平无关(P0.05)。结论:随着疾病的严重程度增加,DN患者血清vaspin呈上升趋势,且与患者的炎症因子呈负相关。检测vaspin水平的变化有助于临床对该病的防治。  相似文献   
62.
摘要 目的:调查肺癌化疗患者癌因性疲乏情况,并分析癌因性疲乏与生存质量、睡眠质量的关系。方法:选取2017年3月至2019年11月期间我院收治的189例肺癌化疗患者。分别采用Piper疲乏修正量表(RPFS)评分、肺癌治疗功能评价系统(FACT-L)评分和匹兹堡睡眠质量指数(PSQI)评分对患者疲乏程度、生存质量和睡眠质量进行评价。采用Pearson检验分析癌因性疲乏与睡眠质量、生存质量的关系。采用单因素及多因素Logistic回归分析癌因性疲乏的影响因素。结果:共发放问卷189份,回收有效问卷182份,回收率为96.30%。182例肺癌化疗患者中,癌因性疲乏发生率为66.48%(121/182)。将发生癌因性疲乏的患者纳为疲乏组(n=121),未发生癌因性疲乏的患者纳为无疲乏组(n=61)。疲乏组FACT-L评分低于无疲乏组,PSQI评分高于无疲乏组(P<0.05)。Pearson相关性分析显示:RPFS评分与FACT-L评分呈负相关,而与PSQI评分呈正相关(P<0.05)。单因素分析显示:无疲乏组与疲乏组组间比较,在文化程度、家庭月收入、血红蛋白、化疗次数、白细胞计数、临床分期、白蛋白方面比较差异均有统计学意义(P<0.05)。多因素Logistic回归分析显示:白细胞计数、家庭月收入、血红蛋白、文化程度、化疗次数、白蛋白、临床分期均为肺癌化疗患者癌因性疲乏的影响因素(P<0.05)。结论:肺癌化疗患者癌因性疲乏越严重,其睡眠质量和生存质量越差,且癌因性疲乏的产生受多种因素的影响,临床实际中应尽可能针对癌因性疲乏的影响因素对患者进行干预。  相似文献   
63.
Li WW  Yu HQ 《Bioresource technology》2011,102(18):8653-8660
Granule-based biological H2 production processes are gaining great popularity in recent years. An efficient and stable operating of such systems relies heavily on the performance of the H2-producing granules (HPGs), which possess many unique properties compared with floc sludge and methanogenic granules. Hence, a full understanding of the sludge characteristics is essential. Especially, the physicochemical properties of HPGs may provide useful information for effective evaluation of system status. This review offers a systematical introduction of the physicochemical properties of HPGs, including size, morphology, settling velocity, permeability, rheology, surface charge, hydrophobicity and extracellular polymeric substances (EPS). We also analyze the relationships between these physicochemical factors and the system performance, and discuss the remaining challenges and future implications for sludge characterization and process monitoring. This work may facilitate a better understanding of granule-based biological H2 production processes and offer a basis for timely process monitoring and manipulation.  相似文献   
64.
This study investigated basal and reciprocal relationships between implicit power motivation (n Power), a preference for having impact and dominance over others, and both salivary estradiol and testosterone in women. 49 participants completed the Picture Story Exercise, a measure of n Power. During a laboratory contest, participants competed in pairs on a cognitive task and contest outcome (win vs. loss) was experimentally varied. Estradiol and testosterone levels were determined in saliva samples collected at baseline and several times post-contest, including 1 day post-contest. n Power was positively associated with basal estradiol concentrations. The positive correlation between n Power and basal estradiol was stronger in single women, women not taking oral contraceptives, or in women with low-CV estradiol samples than in the overall sample of women. Women's estradiol responses to a dominance contest were influenced by the interaction of n Power and contest outcome: estradiol increased in power-motivated winners but decreased in power-motivated losers. For power-motivated winners, elevated levels of estradiol were still present the day after the contest. Lastly, n Power and estradiol did not correlate with self-reported dominance and correlated negatively with self-reported aggression. Self-reported dominance and aggression did not predict estradiol changes as a function of contest outcome. Overall, n Power did not predict basal testosterone levels or testosterone changes as a function of dominance contest outcome.  相似文献   
65.
Short cationic lipopeptides are amphiphilic molecules that exhibit antimicrobial activity mainly against Gram-positives. These compounds bind to bacterial membranes and disrupt their integrity. Here we examine the structure-activity relation (SAR) of lysine-based lipopeptides, with a prospect to rationally design more active compounds. The presented study aims to explain how antimicrobial activity of lipopeptides is affected by the charge of lipopeptide headgroup and the length of lipopeptide acyl chain. The obtained SAR models suggest that the lipophilicity of short synthetic cationic lipopeptides is the major factor that determines their antimicrobial activities. In order to link the differences in antimicrobial activity to the mechanism of action of lipopeptides containing one and two hydrophobic chains, we additionally performed molecular dynamic (MD) simulations. By using combined coarse-grained and all-atom simulations we also show that these compounds neither affect the organization of the membrane lipids nor aggregate to form separate phases. These results, along with the onset of antimicrobial activity of lipopeptides well below the critical micelle concentration (CMC), indicate that lipopeptides do not act in a simple detergent-like manner.  相似文献   
66.
目的:研究川崎病患儿血浆中可溶性内皮细胞蛋白C受体(s EPCR)、一氧化氮(NO)的表达及与炎症反应和冠状动脉病变(CAL)的关系。方法:选择2016年12月至2018年2月盘锦市中心医院收治的川崎病患儿104例为川崎病组,根据患儿彩色超声心动图检测结果将川崎病组分为CAL组30例和非CAL组(NCAL组)74例。另选取同期于我院进行体检的健康儿童56例为对照组。比较川崎病组与对照组、川崎病组患儿急性期与缓解期、CAL组与NCAL组s EPCR、NO、C-反应蛋白(CRP)、白细胞介素-6(IL-6)、肿瘤坏死因子-α(TNF-α)水平,并分析川崎病患儿s EPCR、NO与炎症因子及CAL的相关性。结果:川崎病组患儿s EPCR、NO、CRP、IL-6、TNF-α水平均高于对照组,差异有统计学意义(P0.05)。川崎病组患儿急性期s EPCR、NO、CRP、IL-6、TNF-α水平均高于缓解期,差异有统计学意义(P0.05)。CAL组s EPCR、NO、CRP、IL-6、TNF-α水平均高于NCAL组,差异有统计学意义(P0.05)。经Pearson相关性分析结果显示,川崎病患儿s EPCR、NO与CRP、IL-6、TNF-α及CAL均呈正相关(P0.05)。结论:川崎病患儿s EPCR、NO水平与炎性因子及CAL相关,s EPCR、NO可能在其炎症反应及CAL进展中起到一定的作用。  相似文献   
67.
目的:研究原发性高血压(PH)患者颈动脉粥样硬化、新发心脑血管事件与幽门螺旋杆菌(HP)感染的关系。方法:选择从2015年6月到2017年6月在我院接受诊治的PH患者150例纳入本次研究。按照13C尿素呼气试验所测定的HP结果将患者分成HP阳性59例(即超基准值4.0,记为观察组)和HP阴性91例(即超基准值≥4.0,记为对照组),检测并对比两组血脂指标、超敏C反应蛋白(hs-CRP)、同型半胱氨酸(Hcy)水平以及颈动脉超声检查结果,随访3个月,比较两组新发心脑血管事件。结果:与对照组比较,观察组的低密度脂蛋白型胆固醇(LDL-C)、Hcy及hs-CRP、甘油三酯(TG)、总胆固醇(TC)水平明显升高,高密度脂蛋白型胆固醇(HDL-C)水平明显降低(P0.05)。观察组CIMT增厚率为28.82%,形成斑块率为49.15%,均分别高于对照组的15.38%、30.77%,而CIMT正常率为22.03%,明显低于对照组的53.85%,差异均有统计学意义(P0.05)。观察组新发心脑血管事件的总发生率为13.56%,高于对照组的4.40%,差异有统计学意义(P0.05)。结论:PH患者的颈动脉粥样硬化、新发心脑血管事件均与HP感染密切相关,临床可考虑清除或预防HP感染,从而科学有效地预防患者的不良预后。  相似文献   
68.
Hydroxynaphthoquinone-based inhibitors of the lysine acetyltransferase KAT3B (p300), such as plumbagin, are relatively toxic. Here, we report that free thiol reactivity and redox cycling properties greatly contribute to the toxicity of plumbagin. A reactive 3rd position in the naphthoquinone derivatives is essential for thiol reactivity and enhances redox cycling. Using this clue, we synthesized PTK1, harboring a methyl substitution at the 3rd position of plumbagin. This molecule loses its thiol reactivity completely and its redox cycling ability to a lesser extent. Mechanistically, non-competitive, reversible binding of the inhibitor to the lysine acetyltransferase (KAT) domain of p300 is largely responsible for the acetyltransferase inhibition. Remarkably, the modified inhibitor PTK1 was a nearly non-toxic inhibitor of p300. The present report elucidates the mechanism of acetyltransferase activity inhibition by 1,4-naphthoquinones, which involves redox cycling and nucleophilic adduct formation, and it suggests possible routes of synthesis of the non-toxic inhibitor.  相似文献   
69.

Background

Few studies have investigated the 24-hour symptom profile in patients with COPD or how symptoms during the 24-hour day are inter-related. This observational study assessed the prevalence, severity and relationship between night-time, early morning and daytime COPD symptoms and explored the relationship between 24-hour symptoms and other patient-reported outcomes.

Methods

The study enrolled patients with stable COPD in clinical practice. Baseline night-time, early morning and daytime symptoms (symptom questionnaire), severity of airflow obstruction (FEV1), dyspnoea (modified Medical Research Council Dyspnoea Scale), health status (COPD Assessment Test), anxiety and depression levels (Hospital Anxiety and Depression Scale), sleep quality (COPD and Asthma Sleep Impact Scale) and physical activity level (sedentary, moderately active or active) were recorded.

Results

The full analysis set included 727 patients: 65.8% male, mean ± standard deviation age 67.2 ± 8.8 years, % predicted FEV1 52.8 ± 20.5%.In each part of the 24-hour day, >60% of patients reported experiencing ≥1 symptom in the week before baseline. Symptoms were more common in the early morning and daytime versus night-time (81.4%, 82.7% and 63.0%, respectively). Symptom severity was comparable for each period assessed. Overall, in the week before baseline, 56.7% of patients had symptoms throughout the whole 24-hour day (3 parts of the day); 79.9% had symptoms in ≥2 parts of the 24-hour day. Symptoms during each part of the day were inter-related, irrespective of disease severity (all p < 0.001).Early morning and daytime symptoms were associated with the severity of airflow obstruction (p < 0.05 for both). Night-time, early morning and daytime symptoms were all associated with worse dyspnoea, health status and sleep quality, and higher anxiety and depression levels (all p < 0.001 versus patients without symptoms in each corresponding period). In each part of the 24-hour day, there was also an association between symptoms and a patient’s physical activity level (p < 0.05 for each period).

Conclusions

More than half of patients experienced COPD symptoms throughout the whole 24-hour day. There was a significant relationship between night-time, early morning and daytime symptoms. In each period, symptoms were associated with worse patient-reported outcomes, suggesting that improving 24-hour symptoms should be an important consideration in the management of COPD.

Electronic supplementary material

The online version of this article (doi:10.1186/s12931-014-0122-1) contains supplementary material, which is available to authorized users.  相似文献   
70.
利用ISSR标记,对来源于中国7个省(市)的44个扁蓿豆居群的亲缘关系进行了分析。从80条ISSR引物中筛选出多态性强、重复性好的16条引物,对44个扁蓿豆居群基因组DNA进行扩增,共扩增出133条谱带,平均每个引物扩增出8.31条带,其中多态性带115条,多态性位点百分率为87.08%。扁蓿豆种质间遗传相似系数变化范围在0.436~0.908之间。利用UPGMA聚类分析,44个扁蓿豆居群被划分为8个类群,与地理来源有较高的相关性。  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