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   11094篇
  免费   816篇
  国内免费   414篇
耳鼻咽喉   56篇
儿科学   248篇
妇产科学   157篇
基础医学   2163篇
口腔科学   153篇
临床医学   755篇
内科学   1667篇
皮肤病学   241篇
神经病学   1073篇
特种医学   203篇
外国民族医学   1篇
外科学   902篇
综合类   1277篇
现状与发展   1篇
预防医学   689篇
眼科学   95篇
药学   1511篇
  1篇
中国医学   471篇
肿瘤学   660篇
  2023年   105篇
  2022年   170篇
  2021年   308篇
  2020年   286篇
  2019年   370篇
  2018年   412篇
  2017年   368篇
  2016年   309篇
  2015年   376篇
  2014年   631篇
  2013年   854篇
  2012年   593篇
  2011年   794篇
  2010年   579篇
  2009年   579篇
  2008年   598篇
  2007年   618篇
  2006年   593篇
  2005年   465篇
  2004年   454篇
  2003年   398篇
  2002年   337篇
  2001年   266篇
  2000年   216篇
  1999年   157篇
  1998年   142篇
  1997年   110篇
  1996年   108篇
  1995年   100篇
  1994年   64篇
  1993年   56篇
  1992年   46篇
  1991年   49篇
  1990年   46篇
  1989年   38篇
  1988年   37篇
  1987年   28篇
  1986年   26篇
  1985年   83篇
  1984年   82篇
  1983年   58篇
  1982年   75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 19 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.
《中国现代医生》2019,57(33):43-45+49+169
目的探讨智力障碍相关基因Cdk13对神经轴突伸长的影响。方法通过基因敲除模型、质粒细胞转染等方法,荧光共聚焦显微镜成像技术检测神经元轴突的形态,观察轴突伸长的变化。结果 Cdk12和Cdk13在神经系统中有表达,在敲除Cdk12和Cdk13后轴突长度比对照组减少,两者比较有统计学差异(P0.05),敲除Cdk12和Cdk13基因后Cdk5 mRNA水平降低。结论 Cdk13和Cdk12的表达对神经元轴突的生长至关重要,其失活会引起神经元轴突形态异常,可能是导致智力障碍的病理机制。  相似文献   
10.

Background

Advances in communication technology have enabled new methods of delivering test results to cancer survivors. We sought to determine patient preferences regarding the use of newer technology in delivering test results during cancer surveillance.

Methods

A single institutional, cross-sectional analysis of the preferences of adult cancer survivors regarding the means (secure digital communication versus phone call or office visit) to receive surveillance test results was undertaken.

Results

Among 257 respondents, the average age was 59.1 years (SD 13.5) and 61.8% were female. Common malignancies included melanoma/sarcoma (29.5%), thyroid (25.7%), breast (22.8%), and gastrointestinal (22.0%) cancer. Although patients expressed a relative preference to receive normal surveillance results via MyChart or secure e-mail, the majority preferred abnormal imaging (87.2%) or blood results (85.9%) to be communicated by in-office appointments or phone calls irrespective of age or cancer type. Patients with a college degree or higher were more likely to prefer electronic means of communication of abnormal blood results compared with a telephone call or in-person visit (odds ratio 2.18, 95% confidence interval: 1.01–4.73, P < .05). In contrast, patients >65 years were more likely to express a preference for telephone or in-person communication of normal imaging results (odds ratio: 2.03, 95% CI: 1.16–3.56, P < .05) versus patients ≤65 years. Preference also varied according to malignancy type.

Conclusion

Although many cancer patients preferred to receive “normal” surveillance results electronically, the majority preferred receiving abnormal results via direct conversation with their provider. Shifting routine communication of normal surveillance results to technology-based applications may improve patient satisfaction and decrease health care system costs.  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