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   2287篇
  免费   95篇
  国内免费   124篇
耳鼻咽喉   3篇
儿科学   74篇
妇产科学   18篇
基础医学   346篇
口腔科学   5篇
临床医学   295篇
内科学   621篇
皮肤病学   7篇
神经病学   266篇
特种医学   26篇
外科学   76篇
综合类   306篇
预防医学   192篇
眼科学   5篇
药学   163篇
中国医学   85篇
肿瘤学   18篇
  2024年   2篇
  2023年   12篇
  2022年   32篇
  2021年   51篇
  2020年   49篇
  2019年   72篇
  2018年   93篇
  2017年   51篇
  2016年   66篇
  2015年   46篇
  2014年   171篇
  2013年   160篇
  2012年   132篇
  2011年   156篇
  2010年   123篇
  2009年   70篇
  2008年   149篇
  2007年   114篇
  2006年   110篇
  2005年   86篇
  2004年   77篇
  2003年   82篇
  2002年   65篇
  2001年   70篇
  2000年   49篇
  1999年   68篇
  1998年   64篇
  1997年   47篇
  1996年   43篇
  1995年   34篇
  1994年   29篇
  1993年   25篇
  1992年   28篇
  1991年   12篇
  1990年   10篇
  1989年   10篇
  1988年   8篇
  1987年   10篇
  1986年   8篇
  1985年   5篇
  1984年   6篇
  1983年   2篇
  1982年   1篇
  1980年   1篇
  1979年   2篇
  1978年   3篇
  1976年   2篇
排序方式: 共有2506条查询结果,搜索用时 15 毫秒
1.

Background

It has been reported that particulate matter (PM) is associated with cardiovascular diseases (CVD) while metabolic syndrome is also an important risk factor for CVD. However, few studies have investigated the epidemiological association between PM and metabolic syndrome.

Objective

To investigate the association between one-year exposure to PM with an aerodynamic diameter <2.5?μm (PM2.5) and the risk of metabolic syndrome in Korean adults without CVD.

Methods

Exposure to PM2.5 was assessed using a Community Multiscale Air Quality (CMAQ) model. Metabolic syndrome was defined by National Cholesterol Education Program Adult Treatment Panel III. Andersen and Gill model with time-varying covariates, considering recurrent events, was used to investigate the association between one-year average PM2.5 and the risk of incident metabolic syndrome in 119,998 adults from the national health screening cohort provided by Korea National Health Insurance from 2009 to 2013.

Results

Higher risk of metabolic syndrome, waist-based obesity, hypertension, hypertriglyceridemia, low HDL cholesterol, and hyperglycemia were significantly associated with a 10-μg/m3 increase in PM2.5 [adjusted hazard ratio (HR): 1.070, 1.510, 1.499, 1.468, 1.627 and 1.380, respectively]. In addition, the risk of metabolic syndrome associated with PM2.5 exposure was significant in the consistently obese group (obese at baseline and endpoint).

Conclusion

Exposure to one-year average PM2.5 is associated with an increased risk of metabolic syndrome and its components in adults without CVD. These associations are particularly prominent in the consistently obese group (obese at baseline and endpoint). Our findings indicate that PM2.5 affects the onset of MS and its components which may lead to increase the risk of CVD.  相似文献   
2.
Bipolar disorder (BD) is a common psychiatric mood disorder affecting more than 1-2% of the general population of different European countries. Unfortunately, there is no objective laboratory-based test to aid BD diagnosis or monitor its progression, and little is known about the molecular basis of BD. Here, we performed a comparative proteomic study to identify differentially expressed plasma proteins in various BD mood states (depressed BD, manic BD, and euthymic BD) relative to healthy controls. A total of 10 euthymic BD, 20 depressed BD, 15 manic BD, and 20 demographically matched healthy control subjects were recruited. Seven high-abundance proteins were immunodepleted in plasma samples from the 4 experimental groups, which were then subjected to proteome-wide expression profiling by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight tandem mass spectrometry. Proteomic results were validated by immunoblotting and bioinformatically analyzed using MetaCore. From a total of 32 proteins identified with 1.5-fold changes in expression compared with healthy controls, 16 proteins were perturbed in BD independent of mood state, while 16 proteins were specifically associated with particular BD mood states. Two mood-independent differential proteins, apolipoprotein (Apo) A1 and Apo L1, suggest that BD pathophysiology may be associated with early perturbations in lipid metabolism. Moreover, down-regulation of one mood-dependent protein, carbonic anhydrase 1 (CA-1), suggests it may be involved in the pathophysiology of depressive episodes in BD. Thus, BD pathophysiology may be associated with early perturbations in lipid metabolism that are independent of mood state, while CA-1 may be involved in the pathophysiology of depressive episodes.  相似文献   
3.
不同人群载脂蛋白E基因频率分布特征   总被引:7,自引:0,他引:7  
目的 :研究江苏地区汉族人群载脂蛋白E(ApoE)基因型及等位基因频率 ,并与国内外不同人群比较分布特征。方法 :聚合酶链反应 -限制性片段长度多态性 (PCR -RFLP)方法检测 16 8例江苏地区无血缘关系汉族人群ApoE基因型。计算各基因型及等位基因频率。结果 :江苏地区汉族人群载脂蛋白E各基因型频率分别为 :ε2 / 2 =0 .6 0 % ;ε2 / 3 =11.90 % ;ε2 / 4 =1.2 0 % ;ε3 / 4 =10 .70 % ;ε3 / 3 =75 .0 0 % ;ε4 / 4 =0 .6 0 % ;各等位基因频率分别为 :ε2 =7.14% ;ε3 =86 .31% ;ε4 =6 .5 5 %。频率分布在不同年龄、性别无显著差异。与其他地区中国人群频率分布相似。中国人群ε3 等位基因频率明显高于欧美人群 ,而ε4等位基因频率明显低于欧美人群。结论 :江苏地区汉族人群载脂蛋白E等位基因频率分布与其他地区中国人群频率分布相似 ,但与欧美人群有显著差异。  相似文献   
4.
目的探讨老年高血脂患者血清载脂蛋白CⅡ、CⅢ(Apo CⅡ、CⅢ)的变化及意义.方法免疫比浊法测定老年不同高血脂组血清Apo CⅡ、Apo C Ⅲ水平,并分析与其他指标的相关性.结果老年高血脂患者血清Tch、LDL水平各组间无差异(P>0.05),且与TG浓度无明显相关; TG浓度与HDL水平呈负相关关系(r=0.435,P<0.001),与Apo CⅡ、Apo CⅢ水平呈正相关关系(r=0.478,0.426,P<0.001):老年高血脂患者血清Apo C Ⅱ、Apo CⅢ水平在男女性别间无显著性差异(P>0.05).结论血清Apo CⅡ、Apo CⅢ水平与动脉粥样硬化危险因子TG呈正相关,提示其在老年人心血管疾病的发生中起一定的作用.  相似文献   
5.
载脂蛋白E基因多态性与脑梗死的相关性分析   总被引:12,自引:0,他引:12  
目的 探讨载脂蛋白 E基因多态性与脑梗死的关系。方法 通过聚合酶链反应 -限制性片段长度多态性 (PCR- RFL P)分析结合 DNA直接银染技术检测 6 6例脑梗死 (CI)患者的载脂蛋白 E(Apo E)基因型 (其中家系中有明确脑梗死先证者的家族聚集性脑梗死 (FMACI)亚组 2 6例 ,家系中无脑卒中史的非家族聚集性脑梗死 (NF-MACI)亚组 4 0例 ) ,并与 90例健康对照组比较 ,同时检测血脂、脂蛋白 (a) [L P(a) ]及部分载脂蛋白。结果 脑梗死组ε3/4基因型频率明显高于对照组 (P<0 .0 1) ,ε3/3基因型频率明显低于对照组 (P<0 .0 1) ;两脑梗死亚组之间的ε3/4/ε3/3基因型频率虽有上升 /下降趋势 ,但未发现明显的统计学差异 ;FMACI组高密度脂蛋白 (HDL )水平明显低于 NFMACI组 (P<0 .0 5 )。结论  Apo E基因多态性与脑梗死的发生有关 ,ε4等位基因是脑梗死的易感因子 ,ε3等位基因对脑梗死的发生有保护作用 ;Apo E基因多态性和 HDL水平双重作用于家族聚集性脑梗死的发生。  相似文献   
6.
2型糖尿病患者载脂蛋白E基因多态性的研究   总被引:2,自引:0,他引:2  
目的:探讨中国人2型糖尿病患者载脂蛋白E(apoE)基因多态性及其与血脂和载脂蛋白水平的关系。方法:采用聚合酶链反应-限制性酶切片段长度多态性法,分别对74例2型糖尿病患者及191例血脂、血糖正常且无糖尿病史者的apoE基因型、空腹血脂及载脂蛋白AI、AⅡ、B100、CⅡ、CⅢ及E进行全面分析。结果:2型糖尿病患者的血清甘油三酯(TG)、总胆固醇(TC),低密度脂蛋白胆固醇(LDLC),非高密度脂蛋白胆固醇(nHDLC),载脂蛋白B100、CⅡ、CⅢ、E水平及TG/HDLC比值较对照组显著升高(P<0.01);血清高密度脂蛋白胆固醇(HDLC),apoE/apoCⅢ比值显著降低(P<0.05)。2型糖尿病组与对照组apoE基因频率分布无显著性差异(P>0.05)。携带ε2等位基因组血清TG/HDLC比值较E3/3基因型显著降低;而携带ε4等位基因组血清apoAⅡ水平较E3/3基因型及携带ε2等位基因组显著升高(P<0.001)。结论:2型糖尿病患者apoE基因多态性与血TG/HDLC及apoAⅡ有一定关联。  相似文献   
7.
The serum apolipoprotein A- I (apo A-I) Concentrations in 39 patients with posthepatitis cirrhosis were reported to be 0.87±0.27 g/L lower than that of controls 1.15±0.14 g/L P<0.01. The, decrease of apo. A-I was correlated with the severityof impaired liver function. Apo A- I concentrations in serum correlated positively with decrease of serum albumin (r=0.503 P< 0.01) and negatively with serum bilirubin increase (r=- 0.508 P <0.01) . The data indicate that decreasing of apo A- I concentration may be regarded as one of the reliable indices reflecting the degree of liver function impairment.  相似文献   
8.
陈勇  金权膺 《江苏医药》1992,18(4):179-181
我们对64例糖尿病患者和20名正常人的糖代谢、脂代谢、血小板和血管内皮细胞前列腺素代谢的水平进行了临床观察。发现糖尿病患者载脂蛋白B、低密度脂蛋白胆固醇、总脂固醇、甘油三酯和血栓素B_2的浓度均有不同程度的升高,而载脂蛋白A_1、高密度脂蛋白胆固醇和6-酮前列腺素F_(1α)的浓度则下降。同时糖代谢异常与脂代谢紊乱、糖代谢异常与前列腺素代谢物水平、以及脂代谢紊乱与前列腺素代谢物水平之间均无明显关系。推想糖尿病中促动脉粥样硬化的各种高危因素可能从不同的角度作用于血管壁,促进动脉粥样硬化的发生和发展。  相似文献   
9.
171例高血压患者血脂,脂蛋白及载脂蛋白水平的分析   总被引:1,自引:0,他引:1  
杨万松  范松岚 《天津医药》1992,20(7):393-397
本文就171例HBP患者血脂、脂蛋白及载脂蛋白水平与155例正常人进行比较分析发现:HBP患者WI、TG及apoB较对照组显著升高,TC无明显差别,HDL-C、HDL_2-C及apoAI显著降低、正常男性TC、TG和apoB随年龄增长呈升高趋势,女性TC、TG和LDL-C则在50岁以后开始升高。而HBP患者除男性apoB随年龄增加而升高外,其余各项,不分男女,均无随年龄增减而变化的趋势。  相似文献   
10.
Apolipoprotein E4 (apoE4), the major genetic risk factor of Alzheimer's disease (AD), is associated with enhanced brain inflammation. Genome-wide gene expression profiling was employed to study the effects of apoE genotype on hippocampal gene expression in LPS-treated mice, transgenic for either apoE4 or the AD benign allele, apoE3. This revealed that the expression of inflammation-related genes following intracerebroventricular injection of LPS was significantly higher and more prolonged in apoE4 than in apoE3 transgenic mice. Clustering analysis revealed gene clusters which responded differently in apoE4 and apoE3 mice and were significantly enriched in NF-kappaB response elements. Direct measurement of NF-kappaB-regulated genes revealed that their extent of activation was greater in the apoE4 mice. Immunohistochemistry experiments revealed that microglial and NF-kappaB activation were more pronounced in apoE4 than in apoE3 mice. These findings suggest that the increased brain inflammation in apoE4 mice is related to disregulation of NF-kappaB signaling pathway.  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