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   3248篇
  免费   461篇
  国内免费   32篇
耳鼻咽喉   11篇
儿科学   62篇
妇产科学   30篇
基础医学   234篇
口腔科学   55篇
临床医学   245篇
内科学   390篇
皮肤病学   52篇
神经病学   190篇
特种医学   51篇
外科学   393篇
综合类   547篇
预防医学   393篇
眼科学   18篇
药学   320篇
  1篇
中国医学   616篇
肿瘤学   133篇
  2024年   183篇
  2023年   207篇
  2022年   423篇
  2021年   446篇
  2020年   274篇
  2019年   242篇
  2018年   195篇
  2017年   160篇
  2016年   109篇
  2015年   94篇
  2014年   225篇
  2013年   184篇
  2012年   129篇
  2011年   147篇
  2010年   109篇
  2009年   102篇
  2008年   116篇
  2007年   92篇
  2006年   68篇
  2005年   56篇
  2004年   29篇
  2003年   39篇
  2002年   22篇
  2001年   18篇
  2000年   9篇
  1999年   8篇
  1998年   11篇
  1997年   6篇
  1996年   6篇
  1995年   6篇
  1994年   3篇
  1993年   4篇
  1992年   2篇
  1991年   2篇
  1990年   3篇
  1988年   2篇
  1987年   1篇
  1986年   2篇
  1985年   1篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1977年   1篇
  1973年   1篇
  1970年   1篇
排序方式: 共有3741条查询结果,搜索用时 15 毫秒
101.
设计并建立一套连接医学影像采集设备(如CTM、RIP、ET等)、放疗计划系统(TPS)及医用加速器等大型设备的的放射治疗网络体系工作环境,更充分地发挥局域网络在放射治疗中的作用。在现有大型医疗设备、TPS及局域网环境的基础上,提出两种具有代表性的TPS网络体系解决方案,并结合各自的特点及实际应用情况对其进行了分析和比较。实践证明,放疗计划系统网络体系的建设推进了放射治疗全过程的数字化、网络化,在更大范围内实现了医疗信息资源的共享,在更大程度上发挥了TPS在肿瘤治疗过程中的作用。  相似文献   
102.
103.
A variety of event-related potential (ERP) based studies have shown differences in neuronal processes underlying attention, inhibition and error processing in children with attention-deficit/hyperactivity disorder (ADHD) compared to controls. However, so far there are no studies that have compared children with ADHD and typically developing (TD) children regarding effects in ERP components associated with the attention network test (ANT). The ANT allows to differentiate between three particular aspects of attention: alerting, orienting, conflict.Twenty-five children with ADHD and 19 TD children (comparable with respect to age, sex, and IQ) performed the ANT while ERPs were recorded. Based on DSM-IV, the group of children with ADHD was divided in an inattentive (ADHDin, n = 10) and a combined (ADHDcom, n = 15) subgroup.On the performance level, the ADHD group showed a significantly higher variability of reaction times. Concerning ERP measures, smaller cue-P3 amplitudes were found in the ADHD group indicating that children with ADHD allocate less attentional resources for cue processing. In addition, the target-P3 in ADHD showed smaller amplitudes. Subgroup analysis revealed reduced cue-P3 amplitudes in both subgroups and reduced target-P3 amplitudes in ADHDin compared to TD children. Except for a higher alerting score in ADHD after correction for cue-P3 group differences, performance data revealed no group differences specific for the three attention networks. No group differences related to the attention networks were observed at the ERP level.Our results suggest that deviant attentional processing in children with ADHD is only partly related to ANT-specific effects. Findings are compatible with the model of a suboptimal energetic state regulation in ADHD. Furthermore, our results suggest that deviant cue processing in ADHD and related differences in task modulations should be accounted for in data analysis.  相似文献   
104.
目的:建立一个基于DICOM标准的多参数生理监护局域网系统,实现对病人生理参数的实时监测,为病人提供及时的救助;实现图像和生理波形图共享,医院标准化和信息数字化的全面实施。方法:在深入研究DICOM通信协议模块、DICOM网络协商模块、DICOM存储模块、DICOM查询/获取模块等的基础上,利用Visual C++.Net工具,运用C++面向对象编程思想,将DICOM通信相关PDU封装成类,并采用基于TCP的客户端/服务端(SCU/SCP)Socket网络通信编程模型实现系统的主要功能。结果:建立了一个基于DICOM标准的多参数生理监护局域网系统,这个系统由三个部分组成:多参数生理监护设备,多参数生理监护服务器,多参数生理监护工作站。文章讨论了在DICOM医学波形中SCP和SCU的功能,选择DICOM标准的原因,和该局域网系统的功能。医院对系统进行了评估,评估表示该系统满足临床需要。结论:DICOM标准的不断应用将涵盖所有医学成像和信号类设备,多参数生理监护仪数据的DICOM标准化应用,为将来信号类医疗设备跟医院现有的PACS/RIS、HIS等系统互连融合提供了前提基础。  相似文献   
105.
The present study is a preliminary attempt to use graph theory for deriving distinct features of resting-state functional networks in young adults with autism spectrum disorder (ASD). Networks modeled neuromagnetic signal interactions between sensors using three alternative interdependence measures: (a) a non-linear measure of generalized synchronization (robust interdependence measure [RIM]), (b) mutual information (MI), and (c) partial directed coherence (PDC). To summarize the information contained in each network model we employed well-established global graph measures (average strength, assortativity, clustering, and efficiency) as well as graph measures (average strength of edges) tailored to specific hypotheses concerning the spatial distribution of abnormalities in connectivity among individuals with ASD. Graph measures then served as features in leave-one-out classification analyses contrasting control and ASD participants. We found that combinations of regionally constrained graph measures, derived from RIM, performed best, discriminating between the two groups with 93.75% accuracy. Network visualization revealed that ASD participants displayed significantly reduced interdependence strength, both within bilateral frontal and temporal sensors, as well as between temporal sensors and the remaining recording sites, in agreement with previous studies of functional connectivity in this disorder.  相似文献   
106.
107.
Abstract

At present, no practical method exists for monitoring the progression and severity of cerebral oedema in a clinical setting on a continuous basis. In search for such a method[ we investigated the electrical characteristics of cerebral tissue at microwave frequencies to quantify cerebral oedema. The dielectric constants of normal and oedematous canine cerebral white matter were measured using a Network Analyzer and then compared to the tissue's water content In additioni, salt infiltration and time elapsed after excision of the tissue were examined to determine their effects on the measurements.

The water content and dielectric constant of the white matter were linearly related (correlation coefficient; r = 0.903), comparable to results obtained with a Time Domain Reflectometer in previous research. The Network Analyzer, however; is a more robust measurement device and, because of this, can potentially be used for long term measurements. Further, it was found that neither an increased tissue salt content nor the amount of time after excision of the tissue significantly affected the results. This indicates that the dielectric constant of cerebral white matter is mainly a function of the tissue's water content  相似文献   
108.
ObjectivesWe evaluated breast cancer (BC) care quality indicators (QIs) in clinical pathways and integrated health care processes.MethodsFollowing protocol registration (Prospero no: CRD42021228867), relevant documents were identified, without language restrictions, through a systematic search of bibliographic databases (EMBASE, Scopus, Web of Science, MEDLINE), health care valuable representatives and the World Wide Web in April 2021. Data concerning QIs, measurement tools and compliance standards were extracted from European and North American sources in duplicate with 98% reviewer agreement.ResultsThere were 89 QIs found from 22 selected documents (QI per document mean 13.5 with standard deviation 11.9). The Belgian (38 QIs) and the EUSOMA (European Society of Breast Cancer Specialists) (34 QIs) documents were the ones that best reported the QIs. No identical QI was identified in all the documents analysed. There were 67/89 QIs covering processes (75.3%) and 11/89 (12.4%) for each structure and outcomes QIs. There were 21/89 QIs for diagnosis (30.3%), 43/89 for treatment (48.3%), and 19/89 for staging, counselling, follow-up and rehabilitation (21.4%). Of 67 process QIs and 11 outcome QIs, 20/78 (26%) did not report a minimum standard of care. Shared decision making was only included as a QI in the Italian document.ConclusionMore than half of countries have not established a national clinical pathway or integrated breast cancer care process to achieve the excellence of BC care. There was heterogeneity in QIs for the evaluation of BC care quality. Over two-thirds of the clinical pathways and integrated health care processes did not provide a minimum auditable standard of care for compliance, leaving open the definition of best practice. There is a need for harmonisation of BC care QIs.  相似文献   
109.
There is a paucity of data on the outcome of liver transplantation (LT) in Budd-Chiari Syndrome (BCS) patients who are listed as status 1. The objective of our study was to determine patient or graft survival following LT in status 1 BCS patients. We utilized United Network for Organ Sharing (UNOS) database to identify all adult patients (> 18 years of age) listed as status 1 with a primary diagnosis of BCS in the United States from 1998 to 2018, and analyzed their outcomes and compared it to non-status 1 BCS patients. Four hundred and forty-six patients with BCS underwent LT between 1998 and 2018, and of these 55 (12.3%) were listed as status 1. There was no difference in long-term post-liver transplant or “intention-to-treat” survival from the time of listing to death or the last day of follow-up between status 1 and non-status 1 groups. Graft and patient survival at 5 years for status 1 patients were 75% and 82%, respectively. Cox regression analysis showed that patients listed as status 1 (aHR: 0.45, p < .02) were associated with a better survival. BCS patients listed as status 1 have excellent survival following emergency LT.  相似文献   
110.
COVID-19 has been sweeping the globe, hitting the United States particularly hard with a state of emergency declared on March 13, 2020. Transplant hospitals have taken various precautions to protect patients from potential exposure. OPTN donor, candidate, and transplant data were analyzed from January 5, 2020 to September 5, 2020. The number of new waiting list registrations decreased, with the Northeast seeing over a 50% decrease from the week of 3/8 versus the week of 4/5. The national transplant system saw near cessation of living donor transplantation (−90%) from the week of 3/8 to the week of 4/5. Similarly, deceased donor kidney transplant volume dropped from 367 to 202 (−45%), and other organs saw similar decreases: lung (−70%), heart (−43%), and liver (−37%). Deceased donors recovered dropped from 260 to 163 (−45%) from 3/8 compared to 4/5, including a 67% decrease for lungs recovered. The magnitude of this decrease varied by geographic area, with the largest percent change (−67%) in the Northeast. Despite the pandemic, discard rates across organ has remained stable. Although the COVID-19 pandemic continues to evolve, OPTN data show recent evidence of stabilization, an indication that an early recovery of the number of living and deceased donors and transplants has ensued.  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