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   27289篇
  免费   2490篇
  国内免费   881篇
耳鼻咽喉   314篇
儿科学   466篇
妇产科学   207篇
基础医学   1229篇
口腔科学   634篇
临床医学   3369篇
内科学   1243篇
皮肤病学   619篇
神经病学   568篇
特种医学   4264篇
外国民族医学   16篇
外科学   6106篇
综合类   3409篇
现状与发展   2篇
预防医学   1964篇
眼科学   478篇
药学   1061篇
  5篇
中国医学   400篇
肿瘤学   4306篇
  2024年   17篇
  2023年   353篇
  2022年   442篇
  2021年   886篇
  2020年   866篇
  2019年   827篇
  2018年   856篇
  2017年   800篇
  2016年   935篇
  2015年   968篇
  2014年   1735篇
  2013年   2428篇
  2012年   1521篇
  2011年   1746篇
  2010年   1483篇
  2009年   1460篇
  2008年   1484篇
  2007年   1529篇
  2006年   1334篇
  2005年   1241篇
  2004年   1028篇
  2003年   1026篇
  2002年   816篇
  2001年   808篇
  2000年   621篇
  1999年   470篇
  1998年   395篇
  1997年   293篇
  1996年   256篇
  1995年   233篇
  1994年   194篇
  1993年   171篇
  1992年   155篇
  1991年   159篇
  1990年   125篇
  1989年   130篇
  1988年   114篇
  1987年   104篇
  1986年   93篇
  1985年   108篇
  1984年   83篇
  1983年   66篇
  1982年   61篇
  1981年   52篇
  1980年   52篇
  1979年   45篇
  1978年   20篇
  1977年   19篇
  1976年   25篇
  1975年   13篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
电离辐射会对人体造成损伤,根据受照剂量、时间等因素的不同可诱发多种生物效应。目前对于低剂量辐射产生的健康效应仍有争议,筛选对低剂量敏感的辐射响应生物标志物,对于完善低剂量辐射生物效应机制、拓宽低剂量辐射在临床中的应用均具有重要理论意义。综述探讨各核糖核酸(RNA)在低剂量辐射反应中的变化及其对辐射敏感性的调节作用,同时评估各RNA作为低剂量辐射响应标志物的潜力。  相似文献   
12.
ObjectivesThe aims of this study were to determine the prevalence of sport specialisation in youth football, and to investigate the associations of sport specialisation and volume of sport participation with injury history.DesignCross-sectional questionnaire.SettingNew Zealand youth football teams.Participants414 youth football players aged 10–15 years.Main outcome measuresThe level of specialisation, average weekly sport participation and free-play volume were recorded. 12-month injury history was captured and grouped by injury type. Associations between level of specialisation and demographic variables were analysed using chi square tests. Logistic regression was used to investigate associations between injury history, level of specialisation, and volume of participation.ResultsParticipants were classified as high (43%), moderate (38%), or low (19%) specialised (n = 399 complete). High specialisation was more likely in boys, older participants, and those from large schools. Highly specialised participants were more likely to report a history of gradual onset injury than those who were low specialised (n = 340 with complete injury data). Odds of reporting a gradual onset injury also increased with greater weekly and annual sport participation volume.ConclusionsThere is a high prevalence of sport specialisation in youth football, and it is associated with increased incidence of gradual onset injury.  相似文献   
13.
《Cancer radiothérapie》2022,26(3):502-516
The aim of the review was to present the current literature status about replanning regarding anatomical and dosimetric changes in the target and OARs in the head and neck region during radiotherapy, to discuss and to analyze factors influencing the decision for adaptive radiotherapy of head and neck cancer patients. Significant progress has been made in head and neck patients’ evaluation and qualification for adapted radiotherapy over the past ten years. Many factors leading to anatomical and dosimetric changes during treatment have been identified. Based on the literature, the most common factors triggering re-plan are weight loss, tumor and nodal changes, and parotid glands shrinkage. The fluctuations in dose distribution in the clinical area are significant predictive factors for patients’ quality of life and the possibility of recovery. It has been shown that re-planning influence clinical outcomes: local control, disease free survival and overall survival. Regarding literature studies, it seems that adaptive radiotherapy would be the most beneficial for tumors of immense volume or those in the nearest proximity of the OARs. All researchers agree that the timing of re-planning is a crucial challenge, and there are still no clear consensus guidelines for time or criteria of re-planning. Nowadays, thanks to significant technological progress, the decision is mostly made based on observation and supported with IGRT verification. Although further research is still needed, adaptive strategies are evolving and now became the state of the art of modern radiotherapy.  相似文献   
14.
15.
16.

Aims

Childhood cancer is rare and survival of childhood cancer has increased up to 80% at 5 years after diagnosis. Radiotherapy is an important element of the multimodal treatment concept. However, due to growing tissue, children are particularly sensitive to radiation-related side-effects and the induction of secondary malignancies. However, radiotherapy techniques have continuously progressed. In addition, modern treatment concepts have been improved in order to minimise long-term effects. Today, radiotherapy is used for various tumour types in childhood, such as sarcomas and tumours of the central nervous system.

Materials and methods

External beam therapy with either photons or protons and brachytherapy are predominantly used for the treatment of childhood tumours. Technical developments and features, as well as clinical outcomes, for several tumour entities are presented.

Results

The development of radiotherapy techniques, as well as risk-adapted therapy concepts, resulted in promising outcome regarding tumour control, survival and therapy-related side-effects. It is assumed that proton therapy will be increasingly used for treating children in the future. However, more data have to be collected through multi-institutional registries in order to strengthen the evidence.

Conclusion

The development of radiotherapy techniques is beneficial for children in terms of reducing dose exposure. As compared with other modern and highly conformal techniques, particularly proton therapy may achieve high survival rates and tumour control rates while decreasing the risk for side-effects. However, clinical evidence for modern radiotherapy techniques is still limited today. An optimal patient triaging with the selection of the most appropriate radiation technique for each individual patient will be an important goal for the future.  相似文献   
17.
18.
目的:观察肺癌患者放疗后一氧化氮分数(FeNO)的增加能否提示放射性肺损伤。方法:本研究中,我们评估了FeNO变化与放疗后呼吸症状、CT扫描改变和剂量体积直方图(DVH)参数之间的关系。测量65例肺癌患者放疗前及放疗后4、5、6、10周和4、7.5月的FeNO。结果:在放疗后,11名肺癌患者(17%)自述有明显的呼吸道症状,21名(32%)患者有超过1/3的被照射肺区表现出放射性肺炎样图像。13名患者(20%)的FeNO增加超过10 ppb。以FeNO增加超过10 ppb为标准诊断放疗相关呼吸症状的灵敏度和特异性分别为18%和83%。FeNO变化与放疗后DVH参数或CT扫描改变之间无显著相关性。3名患者(5%)在第4、5周持续表现出异常高水平的FeNO(2或3倍,高达55 ppb),随后出现了显著的呼吸症状和/或放射性肺炎图像。结论:放疗期间的连续FeNO监测预测肺癌患者放射性肺炎症状或图像的能力较差。然而,三名患者表现出的特定模式值得研究。  相似文献   
19.
20.
《Cancer radiothérapie》2020,24(5):423-428
Prostate cancer is the most common malignant tumour and represents the third cause of cancer-mortality in men. The management of prostate cancer has dramatically changed over the last decades, mainly due to improvement of diagnostic modalities and development of new therapeutic strategies. Imaging plays a key role in all the steps of prostate cancer management. In recent years, magnetic resonance imaging (MRI) and positron-emission tomography (PET) – computed tomography (CT) have emerged as two major tools for the detection of prostate cancer, tumour staging and treatment choice. Both MRI and PET-CT – using choline or prostate-specific membrane antigen (PSMA) as radiotracer – have become mandatory. This article presents the contribution of the latest advances in these two imaging techniques of prostate cancer and their future developments.  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