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   5253篇
  免费   227篇
  国内免费   181篇
耳鼻咽喉   5篇
儿科学   17篇
妇产科学   18篇
基础医学   199篇
口腔科学   5篇
临床医学   1269篇
内科学   726篇
皮肤病学   29篇
神经病学   46篇
特种医学   114篇
外科学   1395篇
综合类   944篇
预防医学   382篇
眼科学   1篇
药学   403篇
  14篇
中国医学   76篇
肿瘤学   18篇
  2024年   6篇
  2023年   47篇
  2022年   127篇
  2021年   146篇
  2020年   171篇
  2019年   125篇
  2018年   110篇
  2017年   133篇
  2016年   140篇
  2015年   191篇
  2014年   431篇
  2013年   432篇
  2012年   451篇
  2011年   445篇
  2010年   297篇
  2009年   280篇
  2008年   265篇
  2007年   250篇
  2006年   210篇
  2005年   228篇
  2004年   179篇
  2003年   150篇
  2002年   126篇
  2001年   108篇
  2000年   73篇
  1999年   64篇
  1998年   62篇
  1997年   48篇
  1996年   29篇
  1995年   54篇
  1994年   41篇
  1993年   24篇
  1992年   15篇
  1991年   16篇
  1990年   22篇
  1989年   17篇
  1988年   13篇
  1987年   20篇
  1986年   15篇
  1985年   23篇
  1984年   30篇
  1983年   22篇
  1982年   3篇
  1981年   4篇
  1980年   4篇
  1978年   2篇
  1977年   3篇
  1976年   3篇
  1975年   3篇
  1973年   1篇
排序方式: 共有5661条查询结果,搜索用时 31 毫秒
1.
BackgroundVitamin D is essential in the host defense against tuberculosis (TB). Suboptimal vitamin D status is common in the hemodialysis population. Hemodialysis patients have an increased risk compared to the general population latent tuberculosis infection (LTBI). However, the association between vitamin D deficiency and LTBI in this population remains unclear.Materials and methodsWe conducted a cross-sectional study between March and May 2017. Interferon-gamma release assay (IGRA) through QuantiFERON-TB Gold In-Tube was used to assess LTBI. Plasma 25-hydroxycholecalciferol (25-OHD) levels were measured by Elecsys Vitamin D Total assay. Suboptimal vitamin D levels included vitamin D insufficiency 20–29 ng/mg and vitamin D deficiency <20 ng/mL. Predictors for LTBI were analyzed.ResultsA total of 287 participants were enrolled. The suboptimal vitamin D level was 31.4% (90/287), which including the vitamin D deficiency was 13.9% (40/287). A total of 49.1% (141/287) people received nutritional vitamin D supplementation. The prevalence of IGRA positivity in this study was 25.1% (72/287). There was no significant difference in vitamin D concentrations or the proportion of vitamin D supplementation among the IGRA-positive and IGRA-negative groups (p = 0.789 and 0.496, respectively). In multivariate analysis, age >65 years old (odds ratio (OR), 1.89; 95% CI, 1.08–3.31; p = 0.026) and TB history (OR, 3.51; 95% CI, 1.38–8.91; p = 0.008) were independent predictors of IGRA positivity.ConclusionThis is the first study to report that vitamin D deficiency was not associated with IGRA positivity in a hemodialysis population. Aging and TB history were both independent predictors for LTBI.  相似文献   
2.

Objective

The “Centre Hospitalier Francois Dunan” is located on an isolated island and ensures patients care in hemodialysis thanks to telemedicine support. Many research studies have demonstrated the importance of hemodialysis fluids composition to reduce morbidity in patients on chronic hemodialysis. The aim of this study was to identify the risks inherent in the production of dialysis fluids in a particular context, in order to set up an improvement action plan to improve risk control on the production of dialysis fluids.

Methods

The risk analysis was conducted with the FMECA methodology (Failure Mode, Effects and Criticality Analysis) by a multi professional work group. Three types of risk have been reviewed: technical risks that may impact the production of hemodialysis fluids, health risks linked with chemical composition and health risks due to microbiological contamination of hemodialysis fluids.

Results

The work group, in close cooperation with the expert staff of the dialysis center providing telemedicine assistance, has developed an action plan in order to improve the control of the main risks brought to light by the risk analysis.

Conclusion

The exhaustive analysis of the risks and their prioritisation have permitted to establish a relevant action plan in this improving quality of dialysis fluids approach. The risk control of dialysis fluids is necessary for the security of dialysis sessions for patients, even more when these sessions are realized by telemedicine in Saint-Pierre-et-Miquelon.  相似文献   
3.
4.
Abstract: The risk of cardiovascular death is high in hemodialysis (HD) patients, and thickening, stiffening and calcification of the arterial wall have been shown as its predictive factors. Activated vitamin D preparations are used for the treatment of secondary hyperparathyroidism in HD patients, but as they increase serum phosphate and calcium concentrations, there is a concern that they promote vascular calcification and, consequently, exacerbate the outcomes. In this article, the effects of vitamin D therapy on survival, cardiac function, arteriosclerosis, immunity, and inflammation are evaluated by reviewing the literature. In HD patients, the risk of death (particularly cardiovascular death) is significantly lower in those treated than in those not treated with vitamin D. Moreover, activated vitamin D improves cardiac function and alleviates cardiac hypertrophy in HD patients. Experimental data in cultured macrophages, vascular smooth muscle cells, and vascular endothelial cells suggest that it has antiatherosclerotic effects. In vivo, the administration of vitamin D improves immune functions and normalizes inflammatory reactions. In HD patients, vascular calcification is related to the dose of calcium carbonate, but its relationship with the administration of vitamin D is not significant. These observations suggest that, contrary to the general concerns, activated vitamin D exerts favorable effects on the cardiovascular system in HD patients as long as it is used in appropriate clinical doses.  相似文献   
5.
We report a case of infectious endocarditis in a 77-year-old woman who was undergoing maintenance hemodialysis therapy, and who was also having a prosthetic aortic valve replacement. The disease resulted from a local skin infection at the needle puncture site of the arteriovenous fistula. Ampicillin-resistant Staphylococcus aureus was the causal organism. Surgical treatment could not be performed because of associated intracranial hemorrhage due to septic embolism. In spite of intensive treatment with several antibiotics, a ventricular septal abscess just beneath the prosthetic aortic valve progressed to form a ventricular septal fistula. The resultant intracardiac left-to-right shunt led to refractory congestive heart failure. The patient finally died of heart failure. The formation of a ventricular septal fistula is considered to be a rare and extraordinary complication of infectious endocarditis in a hemodialysis patient with aortic valve replacement. Received: July 25, 2001 / Accepted: November 3, 2001  相似文献   
6.
血液透析动脉穿刺术临床研究   总被引:1,自引:0,他引:1  
目的:研究动脉穿刺技术,提高1次穿刺成功率。方法:将166例急、慢性肾功能衷竭接受血液透析的患者,随机分为观察组84例和对照组82例。观察组用新的穿刺方法,即先在动脉(桡动脉或足背动脉)搏动最明显或最清晰处按一印记,然后进针,对照组用传统的穿刺方法穿刺。比较两组所需时间、1次成功率、血流量、针眼处渗血、疼痛程度以及并发症。结果:两组穿刺所需时间、血流量、针眼处渗血,均有统计学意义(P<0.01)。结论:观察组用新的穿刺方法,能明显提高1次穿刺成功率,缩短穿刺时间,减轻患者痛苦,减少并发症发生。  相似文献   
7.
血清白蛋白水平对血液透析低血压发生的影响   总被引:1,自引:0,他引:1  
目的了解血浆白蛋白水平对血液透析时低血压发生率的影响。方法按血清白蛋白水平分为三组:血清白蛋白>35g/L组、25-35g/L组和<25g/L组,观察三组在血透期间低血压的发生率。结果随着血清白蛋白水平的下降,低血压的发生率呈升高趋势,三组的发生率分别为4.8%,6.4%,25.7%,三组间有显著性差异(P<0.01)。结论血浆白蛋白在维持血透期间的血压起着重要的作用,低白蛋白血症,尤其白蛋白<25g/L时,易发生低血压,在拟定超滤方案时应充分考虑这一因素。  相似文献   
8.
慢性肾病患者常需要建立动静脉内瘘进行透析,常规间断缝合法吻合动静脉难度大、耗时长。为了缩短吻合时间,提高远期通畅率,进行了套叠粘接吻合法建立动静脉内瘘的实验研究,并将这一方法应用于透析患者建立动静脉内瘘的血管吻合。将动脉端套入静脉端,只需吻合两针,用医用胶封闭吻合口。经8个月观察,通畅率达100%,血流量均超过300ml/min。达到了透析需要。  相似文献   
9.
维持性血透患者的心理状态研究   总被引:28,自引:0,他引:28  
研究我国血透患者的心理状况并进行针对性的心理治疗。方法 采用症状自评量表(SCL90-R)、多维度健康状况心理控制源量表(MHLC)、艾森克个性问卷(EPQ)及终末期肾脏病(ESRD)患者专用的生活质量表对北京六个医院透析中心的92名维持性血透患者进行了心理状态的研究,并与美国及加拿大相同的研究进行了比较分析。结果 本组的血透存在着抑郁、焦虑、恐怖等心理障碍,出现心理障碍的比例显著高于美国同类患者(P<0.01),且焦虑的发生率高于美国同类患者(P<0.01)。这些障碍与MHLC中机遇项分(CED)显著相关(P<0.01)。EPQ中神经质项分高者倾向于发生抑郁、焦虑等心理障碍。本组的血透患者客观生活质量较加拿大同类患者低(P<0.01),但在总的生活满意度上没有显著性差异。生活质量与心理及躯体因素均呈显著相关,心理障碍与躯体症状也显著相关(P<0.01)。结论 本组的血透患者心理状态与美国加拿大同类患者相比既有相同之处,又有特殊之处。我们应该兼顾病人的躯体和精神两方面的健康,努力提高他们的生活质量。  相似文献   
10.
目的研究IFN-γ,IL-4水平对血透患者外周血淋巴细胞(PBLC)凋亡调控蛋白Fas,Bcl-2表达的影响.方法采用流式细胞术的间接免疫荧光素标记法和双抗体夹心ELISA法,分别检测30例HD患者PBLC Fas,Bcl-2的表达水平和血清IFN-γ,IL-4水平.结果H-D患者血清IFN-γ水平明显低于健康对照组,IL-4浓度显著高于对照组(P均<0.01);其外周血PBLC的Fas表达水平明显高于健康对照组,而Bcl-2水平则明显低于健康对照组(P均<0.01).经相关分析发现:Fas表达水平与血清IFN-γ水平呈负相关,而与血清IL-4水平呈正相关(P均<0.01);Bcl-2表达水平与血清IFN-γ水平呈正相关,而与血清IL-4水平呈负相关(P均<0.01).结论HD患者PBLC存在异常凋亡现象;并与Th1型细胞因子分泌低下,以及TTh2型细胞因子分泌增加之间有一定的相关性,上述改变可能在HD患者的免疫功能紊乱中起着重要作用.  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