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   52816篇
  免费   4590篇
  国内免费   931篇
耳鼻咽喉   272篇
儿科学   2391篇
妇产科学   856篇
基础医学   5325篇
口腔科学   1075篇
临床医学   6907篇
内科学   8114篇
皮肤病学   723篇
神经病学   929篇
特种医学   883篇
外国民族医学   1篇
外科学   6068篇
综合类   7521篇
现状与发展   7篇
预防医学   10250篇
眼科学   303篇
药学   4391篇
  43篇
中国医学   1109篇
肿瘤学   1169篇
  2024年   164篇
  2023年   970篇
  2022年   1927篇
  2021年   2538篇
  2020年   2564篇
  2019年   2022篇
  2018年   1941篇
  2017年   1910篇
  2016年   2051篇
  2015年   2211篇
  2014年   3644篇
  2013年   4133篇
  2012年   3574篇
  2011年   3673篇
  2010年   2602篇
  2009年   2411篇
  2008年   2280篇
  2007年   2352篇
  2006年   2220篇
  2005年   1943篇
  2004年   1603篇
  2003年   1371篇
  2002年   995篇
  2001年   903篇
  2000年   745篇
  1999年   703篇
  1998年   559篇
  1997年   520篇
  1996年   453篇
  1995年   437篇
  1994年   408篇
  1993年   338篇
  1992年   309篇
  1991年   293篇
  1990年   210篇
  1989年   226篇
  1988年   175篇
  1987年   140篇
  1986年   108篇
  1985年   144篇
  1984年   97篇
  1983年   77篇
  1982年   85篇
  1981年   71篇
  1980年   48篇
  1979年   48篇
  1978年   29篇
  1977年   28篇
  1976年   34篇
  1975年   15篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
11.
混合Poisson分布及其应用:疾病的统计分布(五)   总被引:4,自引:0,他引:4  
本文讨论了混合Poisson分布的性质、应用条件、参数的估计及混合Poisson分布阶数的确定,指出混合Poisson分布可用于混合样本的判别归类,并用Bayes的思想导出其判别归类方法。模拟试验结果表明:当混合Poisson分布中各部分的比例相差不大,而各部分的均值相差较大时,抽样效果和拟合效果越好,所得到的估计值越接近理论值;反之效果越差。  相似文献   
12.
This article describes the association between previous infection and/or vaccination and the development of optic neuritis (ON) in 18 children. Ten of these children subsequently developed clinically definite multiple sclerosis (MS), while in 8 patients a clinically definite etiology could not be confirmed. Vaccination preceded the first ON attack in 6 patients, all but one of whom subsequently developed MS. It also preceded subsequent demyelinating events in 6 patients. Ten of the patients had a bacterial or viral infection within the 2 weeks prior to the first symptoms of ON. Intrathecal antibody synthesis against 2 or more viruses could be shown in 5 out of 8 patients studied; 5 out of 6 patients had oligoclonal antibodies in CSF and 12 out of 16 patients a high IgG index. Neither intrathecal antibody synthesis against 2 or more viruses nor elevated IgG indexes could be found in the control patients. Measles and mumps occurred at a significantly later age in the children who subsequently developed MS than in the control children, and these patients had significantly more events that might have impaired the blood-brain barrier than the controls. These results indicate that immunological events leading to MS may be triggered during childhood. Vaccination and infection often precede ON in childhood. Intrathecal viral antibody production can occur already in childhood at the time of the first symptoms of MS.  相似文献   
13.
Permissive herpes simplex virus (HSV) infection in tissue culture results in host cell destruction. Latent HSV infection in vivo occurs in neurons of peripheral sensory ganglia (PSG) and it therefore can not take place in neurons in which the virus has completed a lytic replication cycle similar to that present in vitro. Our hypothesis, based on experimental data and observations in humans, suggests that establishment of latent infection and reactivation of HSV-1 does not involve neuronal cell loss. Latency is established in neurons in which the virus does not replicate and is determined, in part, by the tissue levels of a herpes transactivating protein (Vmw65) that is a component of the viral tegument. We also suggest that reactivation of latent infection does not involve destruction of neurons and is due to replication of virus at the peripheral mucocutaneous tissues to where virus or viral DNA have been transported from the nervous tissue. Alternatively, reactivation is initiated in the PSG using a replication cycle which does not involve irreversible damage to neurons. This model explains the lack of damage to neurons which continue to serve as permanent reservoirs of latent virus for the entire life of the host.  相似文献   
14.
15.
Background : Severe odontogenic infections are serious potentially lethal conditions. Following the death of a patient in the authors' institution this study was initiated to determine the risk factors, management and outcome of a consecutive series of patients.
Methods : All patients admitted to the Royal Adelaide Hospital under the care of the Oral and Maxillofacial Surgery Unit with odontogenic infections in calendar year 2003 were investigated. Detailed information relative to their pre-presentation history, surgical and anaesthetic management and outcome was obtained and analysed.
Results : Forty-eight patients, 32M, 16F, average age 34.5, range 19 to 88 years were treated. All presented with pain and swelling, with 21 (44 per cent) having trismus. Forty-four (92 per cent) were as a result of dental neglect and four (8 per cent) were regular dental patients having endodontic treatment which failed. Of those known to have been treated prior to presentation, most had been on antibiotics. Most patients had aggressive surgical treatment with extraction, surgical drainage, high dose intravenous antibiotics and rehydration. The hospital stay was 3.3 (range 1–16) days. Patients requiring prolonged intubation and high dependency or intensive care (40 per cent) had longer hospitalization. No patient died and all fully recovered.
Conclusion : Severe odontogenic infections are a serious risk to the patient's health and life. Management is primarily surgical with skilled anaesthetic airway management. Antibiotics are required in high intravenous doses as an adjunct and not as a primary treatment.  相似文献   
16.
支气管肺蠊缨滴虫感染是一种新的寄生虫疾病,1993年至2008年国内共确诊48例,临床诊断和治疗有一定进展,但蠊缨滴虫感染病例的临床表现缺少特征性,蠊缨滴虫自然宿主、传播途径、流行区域及致病机制等多个方面也尚不明确,其生物学分类地位也有争议,国内还没有建立抗原抗体检测或分子生物学鉴定方法.  相似文献   
17.
Necrotizing soft tissue infections (NSTI) represent a spectrum of diseases characterized by extensive rapidly progressive necrosis that may involve the skin, subcutaneous tissues, fascia or muscle. Their progress is extremely fast, leading often to sepsis and septic shock that ends up in multiple organ failure with abrupt and high mortality. A variety of classification systems have been developed based on parameters such as anatomic location of the disease or microbiology. There are a number of factors that predispose to the spread of these soft tissue infections, such as delays in recognition, immune suppression, diabetes mellitus and advanced age. The use of broad‐spectrum antibiotics tends to mask the severity of the underlying infection, modulates the clinical presentation, and even delays hospital admission. The most important factor affecting outcome in NSTI is early diagnosis and aggressive radical surgical treatment. The medical records of 13 patients who had been treated for NSTI from 1996 to 2005 were reviewed, retrospectively. There were eight men (61.5%) and five (38.5%) women. Mean age was 56 years (range 27–73). Seven cases of infection involved the perineal region (54%), two the lower limb, one the upper limb and three the abdominal wall/trunk. The most common associated comorbidity was diabetes mellitus in five patients (38.5%). A single organism was identified in two (15%) and multiple organisms in 11 (85%) patients. Necrotizing aponeurositis Type I was the most common of the polymicrobial necrotizing infections. Overall survival was 85%, and the mean hospital stay for survivors was 35 days (range 17–92).  相似文献   
18.
路桂华 《护理研究》2004,18(13):1133-1135
[目的 ]探讨自拟消咳贴穴位贴敷治疗小儿反复呼吸道感染 (RRI)的临床效果。 [方法 ]选择 15 0例RRI患儿 ,随机分为观察组和对照组 ,观察组在对因对症治疗基础上应用自拟消咳贴穴位贴敷 ,对照组采用对因对症治疗 ;另选 3 0例正常儿童 ,观察血浆内皮素 (ET -1)、一氧化氮 (NO)变化及临床疗效。 [结果 ]观察组治疗后血浆ET -1、NO含量明显下降 (P <0 .0 1) ,而对照组治疗前后则无统计学意义 ;观察组临床总有效率高于对照组 (P <0 .0 1) ,且每月发病次数及天数也明显降低。 [结论 ]应用自拟消咳贴穴位贴敷能有效地降低RRI患儿血浆ET -1、NO水平 ,从而提高临床疗效  相似文献   
19.
AIM: To undertake a systematic review of the diagnostic performance of clinical examination, sample acquisition and sample analysis in infected foot ulcers in diabetes. METHODS: Nineteen electronic databases plus other sources were searched. To be included, studies had to fulfil the following criteria: (i) compare a method of clinical assessment, sample collection or sample analysis with a reference standard; (ii) recruit diabetic individuals with foot ulcers; (ii) present 2 x 2 diagnostic data. Studies were critically appraised using a 12-item checklist. RESULTS: Three eligible studies were identified, one each on clinical examination, sample collection and sample analysis. For all three, study groups were heterogeneous with respect to wound type and a small proportion of participants had foot ulcers due to diabetes. No studies identified an optimum reference standard. Other methodological problems included non-blind interpretation of tests and the time lag between index and reference tests. Individual signs or symptoms of infection did not prove to be useful tests when assessed against punch biopsy as the reference standard. The wound swab did not perform well when assessed against tissue biopsy. Semiquantitative analysis of wound swab might be a useful alternative to quantitative analysis. The limitations of these findings and their impact on recommendations from relevant clinical guidelines are discussed. CONCLUSION: Given the importance of this topic, it is surprising that only three eligible studies were identified. It was not possible to describe the optimal methods of diagnosing infection in diabetic patients with foot ulceration from the evidence identified in this systematic review.  相似文献   
20.
封闭式负压引流治疗软组织感染   总被引:3,自引:0,他引:3  
目的探讨封闭式负压引流治疗软组织感染的疗效。方法应用封闭式负压引流治疗开放性骨折发生软组织感染18例。结果18例均获随访,时间6个月-1年6个月。软组织感染均愈合,骨折正常愈合12例,延迟愈合6例,无慢性骨感染发生。结论封闭式负压引流治疗软组织感染,可短期控制感染,为进一步治疗创造条件,尤其适用于深部软组织感染患者。手术简单,疗效可靠,适合基层医院应用。  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