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   20072篇
  免费   1390篇
  国内免费   758篇
医药卫生   22220篇
  2023年   170篇
  2022年   343篇
  2021年   554篇
  2020年   552篇
  2019年   498篇
  2018年   566篇
  2017年   607篇
  2016年   630篇
  2015年   703篇
  2014年   1190篇
  2013年   1447篇
  2012年   1215篇
  2011年   1455篇
  2010年   1155篇
  2009年   1088篇
  2008年   1114篇
  2007年   1118篇
  2006年   1038篇
  2005年   896篇
  2004年   824篇
  2003年   665篇
  2002年   513篇
  2001年   410篇
  2000年   396篇
  1999年   277篇
  1998年   247篇
  1997年   257篇
  1996年   307篇
  1995年   313篇
  1994年   247篇
  1993年   212篇
  1992年   118篇
  1991年   121篇
  1990年   87篇
  1989年   77篇
  1988年   58篇
  1987年   46篇
  1986年   37篇
  1985年   90篇
  1984年   88篇
  1983年   61篇
  1982年   79篇
  1981年   67篇
  1980年   50篇
  1979年   39篇
  1978年   29篇
  1977年   26篇
  1976年   28篇
  1975年   33篇
  1973年   24篇
排序方式: 共有10000条查询结果,搜索用时 296 毫秒
1.
BackgroundFew studies have investigated the impact of web-based physical activity interventions on mental health outcomes. Therefore, this study examined the impact of a web-based personally tailored physical activity intervention on depression, anxiety, stress and quality of life.Methods501 participants were randomised into either a control group or a pooled intervention condition who received a 3-month web-based personally tailored physical activity intervention. Previously, this intervention has demonstrated to improve self-reported physical activity, but not device-measured physical activity. At baseline, 3- and 9-months, depression, anxiety and stress were assessed using the DASS21, and quality of life was assessed using the SF-12V2. General linear mixed models examined differences between groups over time.ResultsMost participants (>80%) reported normal levels of depression, anxiety or stress. Relative to baseline levels, significant reductions of depression, anxiety, stress and the SF12 mental health component were observed in the pooled intervention group at 3 and 9 months. Relative to the control group, significant reductions were observed in the pooled intervention group for depression and stress (3-months only) and anxiety (3- and 9-months), but not quality of life.ConclusionA web-based physical activity intervention can result in positive mental health outcomes, even in the absence of device-measured physical activity improvements. However, these findings need to be confirmed in future studies.Trial registration numberACTRN12615000057583.  相似文献   
2.
目的:探讨脑出血对酵母沉默信息调节因子2(Sirt2)和炎症的影响。方法:将胶原酶Ⅳ注入SD大鼠右侧 纹状体中建立脑出血模型,通过免疫印迹和ELISA 等方法测定大鼠脑出血后48 h 的Sirt2 的表达及炎症变化。利 用Hemin 诱导PC12 细胞损伤模拟体外脑出血模型,并检测Sirt2 及炎症变化;采用短发夹RNA(shRNA)-Sirt2 沉 默Sirt2 在PC12 细胞中的表达及对炎症的影响。结果:手术后48 h 脑出血行为学评分最低。脑出血组Sirt2 的表达 显著高于假手术组。脑出血组IL-6、IL-1β 表达显著升高。结论:脑出血可以促进Sirt2 的表达和炎症反应,降低 Sirt2 的表达可减缓炎症反应。 关键词 脑出血;沉默信息调节  相似文献   
3.
PurposeThe variation in the immune response to Bartonella spp. infection in humans remains unclear. The present study compares the expression of selected interleukins, cytokines and cathelicidin (LL-37) in rheumatology clinic patients suffering from musculoskeletal symptoms with healthy blood donors. The patients had previously been tested for the presence of Bartonella henselae antibodies.MethodsGene expression of LL-37, interleukin (IL)-2, IL-4, IL-6, IL-12, interferon-(IFN)-γ, and tumor necrosis factor (TNF-α)-α was determined in blood samples using quantitative Polymerase Chain Reaction (qPCR). Statistical analysis was prepared with STATISTICA.ResultsStatistically significant differences in the mRNA levels of the tested cytokines (IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-12; p<0.0001) were observed between the healthy controls and patients; however, no difference was observed for LL37 mRNA (p ?= ?0.1974). No significant differences in mRNA expression were observed between IgG in anti-Bartonella seropositive and seronegative individuals (p>0.05). The only significant differences between the Bartonella spp. DNA positive and negative patients, indicated by PCR, were observed for TNF-α and IL-12 mRNA (p ?= ?0.0045 and p ?= ?0.0255, respectively).ConclusionA broadly similar immune response to the tested cytokines was observed among the participants irrespective of anti-Bartonella spp. IgG seropositivity. However, the Bartonella DNA-positive participants demonstrated significantly lower expression of IL-12 and TNF-α mRNA; this may indicate that these bacteria have a suppressive influence on the immune system.  相似文献   
4.
田玥  邹健 《现代肿瘤医学》2022,(23):4377-4382
胃癌作为临床最常见的肿瘤之一,常因确诊疾病较晚而影响治疗效果,胃镜活检后的病理虽然作为确诊的金标准,但是由于此方式过程痛苦,操作复杂,费用较高,且具有侵入性,可能会导致患者拒绝操作而难普及于临床,因此积极找寻胃癌有效的监测指标十分必要。近年来,很多学者研究维生素与胃癌的相关关系,并试图通过摄取某些维生素降低胃癌发生率,延缓病情及改善预后,也有通过检测血清中维生素的水平给早期胃癌的诊断提供帮助。本文就同型半胱氨酸、维生素D、维生素C、维生素E、维生素B12及叶酸在胃癌中的作用机制,及其在血清中水平与胃癌关系的相关研究进展进行简要综述,为临床胃癌诊疗提供新思路。  相似文献   
5.
6.
BackgroundGlioma accounts for most central nervous system tumors, and the degree of invasion and malignancy are higher in the recurrent glioma. Photodynamic therapy (PDT) is an effective strategy in glioma. This study aimed to explore the risk factors for re-recurrence after a second glioma surgery and the effects of PDT on re-recurrence.MethodsThis was a retrospective study in the Second Affiliated Hospital of Harbin Medical University in China, and 43 patients that received the secondary surgery for recurrent glioma were included. The Kaplan-Meier test and Cox proportional hazard method were used to analyze.ResultsThe total re-recurrence rate after the second surgery for recurrent glioma was 48.84%. When the age increased by 1, the risk of re-recurrence increased 1.065 times (95% CI 1.000–1.134, P = 0.049). High matrix metalloproteinase (MMP) 2 expression was associated with a significantly higher risk of re-recurrence than low MMP2 expression (HR = 25.550, 95% CI 3.190–204.650, P = 0.002). Pathological grades IV and III were associated with a significantly higher risk of re-recurrence than pathological grade II (HR = 17.121, 95% CI 2.345–124.986, P = 0.005; HR = 2863.470, 95% CI 100.697–81,427.197, P < 0.001). PDT decreased the risk of re-recurrence (HR = 25.550, 95% CI 3.190–204.650, P = 0.002) and increased survival time (HR = 3.611, 95% CI 1.012–12.888, P = 0.048).ConclusionThe age, MMP2 expression, and pathological grade are independent risk factors for re-recurrence after a second surgery for recurrent glioma. PDT during the second surgery decreased the risk of re-recurrence and increased survival time.  相似文献   
7.
8.
9.
10.
BackgroundIschemia reperfusion (I/R) play an imperative role in the expansion of cardiovascular disease. Sinomenine (SM) has been exhibited to possess antioxidant, anticancer, anti-inflammatory, antiviral and anticarcinogenic properties. The aim of the study was scrutinized the cardioprotective effect of SM against I/R injury in rat.MethodsRat were randomly divided into normal control (NC), I/R control and I/R + SM (5, 10 and 20 mg/kg), respectively. Ventricular arrhythmias, body weight and heart weight were estimated. Antioxidant, inflammatory cytokines, inflammatory mediators and plasmin system indicator were accessed.ResultsPre-treated SM group rats exhibited the reduction in the duration and incidence of ventricular fibrillation, ventricular ectopic beat (VEB) and ventricular tachycardia along with suppression of arrhythmia score during the ischemia (30 and 120 min). SM treated rats significantly (P < 0.001) altered the level of antioxidant parameters. SM treatment significantly (P < 0.001) repressed the level of creatine kinase MB (CK-MB), creatine kinase (CK) and troponin I (Tnl). SM treated rats significantly (P < 0.001) repressed the tissue factor (TF), thromboxane B2 (TXB2), plasminogen activator inhibitor 1 (PAI-1) and plasma fibrinogen (Fbg) and inflammatory cytokines and inflammatory mediators.ConclusionOur result clearly indicated that SM plays anti-arrhythmia effect in I/R injury in the rats via alteration of oxidative stress and inflammatory reaction.  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