首页 | 官方网站   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   171529篇
  免费   14208篇
  国内免费   9793篇
医药卫生   195530篇
  2024年   372篇
  2023年   1600篇
  2022年   4164篇
  2021年   5858篇
  2020年   4602篇
  2019年   3872篇
  2018年   4108篇
  2017年   4388篇
  2016年   4452篇
  2015年   7018篇
  2014年   9107篇
  2013年   10022篇
  2012年   14559篇
  2011年   15261篇
  2010年   12061篇
  2009年   10468篇
  2008年   11925篇
  2007年   11705篇
  2006年   10885篇
  2005年   9500篇
  2004年   7410篇
  2003年   7481篇
  2002年   6130篇
  2001年   4731篇
  2000年   3491篇
  1999年   2277篇
  1998年   1253篇
  1997年   1320篇
  1996年   907篇
  1995年   758篇
  1994年   630篇
  1993年   418篇
  1992年   443篇
  1991年   396篇
  1990年   322篇
  1989年   269篇
  1988年   228篇
  1987年   208篇
  1986年   156篇
  1985年   155篇
  1984年   83篇
  1983年   71篇
  1982年   55篇
  1981年   38篇
  1980年   28篇
  1979年   47篇
  1978年   46篇
  1976年   24篇
  1975年   23篇
  1973年   35篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Abstract

Background

Comorbidities are commonly seen in patients with coronavirus disease 2019 (COVID-19), but the clinical implication is not yet well-delineated. We aim to characterize the prevalence and clinical implications of comorbidities in patients with COVID-19.  相似文献   
2.
Membrane trafficking processes are presumably vital for axonal regeneration after injury, but mechanistic understanding in this regard has been sparse. A recent loss-of-function screen had been carried out for factors important for axonal regeneration by cultured cortical neurons and the results suggested that the activity of a number of Rab GTPases might act to restrict axonal regeneration. A loss of Rab27b, in particular, is shown to enhance axonal regeneration in vitro, as well as in C. elegans and mouse central nervous system injury models in vivo. Possible mechanisms underlying this new finding, which has important academic and translational implication, are discussed.  相似文献   
3.
通过文献研究、问卷调查、专家访谈、现地调研等方法,分析医院离退休干部参与社会治理的现状及影响因素,探讨社区对离退休干部参与社会治理的需求,提出通过党建引领医院离退休干部参与社会治理的“1235”模式,并给出具体的操作路径,以期为推动医院离退休干部积极参与社会治理提供参考。  相似文献   
4.
Objective Ligustrazine, also named as tetramethylpyrazine, is a compound purified from Ligusticum chuanxiong hort and has ever been testified to be a calcium antagonist. The present investigation was to determine the antinoci-ceptive effect of ligustrazine and, if any, the peripheral ionic mechanism involved. Methods Paw withdrawal Latency ( PWL) to noxious heating was measured in vivo and whole-cell patch recording was performed on small dorsal root ganglion (DRG) neurons. Results Intraplantar injection of ligustrazine (0.5 mg in 25μl) significantly prolonged the withdrawal latency of ipsilateral hindpaw to noxious heating in the rat. Ligustrazine not only reversibly inhibited high-voltage gated calcium current of dorsal root ganglion (DRG) neuron in dose-dependent manner with IC50 of 1.89 mmol/L, but also decreased tetrodotoxin (TTX) -resistant sodium current in relatively selective and dose-dependent manner with IC50 of 2.49 mmol/L. Conclusion The results suggested that ligustrazine could elevate the threshold of thermal nociception through inhibiting the high-voltage gated calcium current and TTX-resistant sodium current of DRG neuron in the rat.  相似文献   
5.
重型颅脑损伤的手术治疗   总被引:5,自引:1,他引:4  
目的探讨重型颅脑损伤梯度减压的手术方法对预防术中脑膨出、降低死亡率及致残率的效果。方法对100例重型颅脑损伤患者采用分次减压手术方式及去骨瓣后,硬膜与颞肌筋膜瓣减张缝闭硬膜切口方法。结果40例脑肿胀患者术中脑嘭出6例占15.0%,死亡19例占47.5%;60例脑内血肿病人未发生脑膨出,死亡12例占20%。结论脑外伤后脑血管调节麻痹及血肿压迫继发脑水肿易造成脑膨出.术中分次减压降低了骨窗部位脑组织的顺应性,从而降低了局部的压力梯度,避免脑血管急性扩张,能有效防止脑膨出,降低死亡率及致残率。  相似文献   
6.
关节镜辅助下钢板内固定治疗关节内跟骨骨折   总被引:3,自引:1,他引:2  
[目的]探讨分析关节镜辅助下钢板内固定治疗关节内跟骨骨折的方法和疗效;[方法]对78位患者,86例累及关节面的跟骨骨折在关节镜辅助下行切开复位钢板内固定术,术后平均随访18个月(12~30个月),通过比较术前术后X线片和踝足功能的AOFAS评分对治疗效果作分析评价.[结果]86例关节内跟骨骨折术后X线示复位满意.与术前存在显著性差异(P〈0.01),AOFAS评分优良率91.86%.[结论]对于关节内跟骨骨折,采用关节镜辅助钢板内固定更加接近解剖复位,足部功能恢复满意且并发症少  相似文献   
7.
带浅静脉干逆行皮瓣早期微血管构筑变化的体视学研究   总被引:4,自引:0,他引:4  
目的 探讨带浅静脉干的逆行皮瓣早期微血管构筑变化的特点以供临床实践参考。方法 应用生物体视学技术测量带浅静脉干皮瓣微血管体积密度,结合组织学观察,与不带静脉干皮瓣作对照比较。结果 带浅静脉干皮瓣组微血管密度整体水平高于不带静脉干皮瓣组(P〈0.05)。结论 浅静脉干的存在有利于皮瓣的血管化进程,保留浅静脉干对皮瓣成活有利。  相似文献   
8.
Generally, a computed tomography scan is conducted for the diagnosis of stroke in the emergency department, because these scans are easier and faster in the detection of stroke. If there are no signs of hemorrhage on computed tomography scan, an ischemic stroke is diagnosed and treated accordingly. A magnetic resonance imaging scan may be taken in order to verify ischemic stroke. This process may lead to improper treatment and is time consuming. To address this situation, case studies are presented in which magnetic resonance imaging diffusion-weighted imaging and gradient recalled echo were performed to detect hemorrhagic and ischemic stroke and particularly, subarachnoid hemorrhage, which is undetectable with a computed tomography scan.  相似文献   
9.
The aim of the study was to analyse the clinical manifestation and management of pulmonary Lophomonas blattarum infection in four allograft transplantation recipients retrospectively. Four patients with pulmonary L. blattarum infection were diagnosed by using Fiberoptic bronchoscopy (FOB) and bronchoalveolar lavage (BAL) examination. Their clinical manifestation and management are summarized. Four cases of pulmonary L. blattarum were found during the period from the second month to the third month after transplantation. Concurring infection by other pathogens was found in three of them. Common initial symptoms included fever (>38 degrees C) without cough and breathlessness. Lower lobe shadowing could be found on chest X-ray. Body temperature decreased to the normal range in three patients and to 37.5 degrees C in the other one, after intravenous injection of metronidazole and tapering immunosuppressant. Radiological examination confirmed improved health condition of the patients afterwards. Two patients received repeated FOB and only dead L. blattarum was found. Pulmonary L. blattarum infection in allograft transplant recipients carry relatively obscure initial symptoms. Possible L. blattarum infection needs to be screened in post-transplantation pulmonary infection patients with similar symptoms, especially in those who respond poorly to anti-infection treatment. Microscopic examination of BAL fluid can help to identify pulmonary L. blattarum infection and metronidazole is an ideal treatment choice.  相似文献   
10.
目的 探讨Lugol液染色对食管早期癌和癌前病变的诊断价值。方法 对45例食管黏膜可疑病变经内镜以2%Lugol液喷洒染色,观察黏膜染色情况,并取活检送病理组织学检查。结果 45例食管病变染色后,39例呈浅染色或不染色,其中食管癌8例(食管早期癌5例,进展期癌3例),Barrett食管5例,轻至中度不典型增生1l例。本组Lugol液染色对食管早期癌和癌前病变的检出率达46.7%。结论 内镜下应用Lugol液染色结合活检有助于食管早期癌和癌前病变的诊断,且操作简便,具有重要的临床价值。  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-23

京公网安备 11010802026262号