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   12505篇
  免费   1599篇
  国内免费   281篇
耳鼻咽喉   46篇
儿科学   146篇
妇产科学   109篇
基础医学   1024篇
口腔科学   178篇
临床医学   1081篇
内科学   1103篇
皮肤病学   69篇
神经病学   616篇
特种医学   456篇
外科学   850篇
综合类   2194篇
现状与发展   1篇
一般理论   8篇
预防医学   3741篇
眼科学   109篇
药学   1435篇
  8篇
中国医学   731篇
肿瘤学   480篇
  2024年   97篇
  2023年   424篇
  2022年   682篇
  2021年   929篇
  2020年   833篇
  2019年   699篇
  2018年   605篇
  2017年   660篇
  2016年   593篇
  2015年   533篇
  2014年   902篇
  2013年   1012篇
  2012年   574篇
  2011年   683篇
  2010年   508篇
  2009年   476篇
  2008年   517篇
  2007年   513篇
  2006年   486篇
  2005年   404篇
  2004年   361篇
  2003年   302篇
  2002年   248篇
  2001年   168篇
  2000年   126篇
  1999年   97篇
  1998年   101篇
  1997年   98篇
  1996年   70篇
  1995年   54篇
  1994年   70篇
  1993年   59篇
  1992年   50篇
  1991年   50篇
  1990年   42篇
  1989年   49篇
  1988年   36篇
  1987年   46篇
  1986年   34篇
  1985年   29篇
  1984年   29篇
  1983年   18篇
  1982年   24篇
  1981年   11篇
  1980年   23篇
  1979年   8篇
  1978年   8篇
  1977年   8篇
  1976年   11篇
  1974年   7篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
临床试验数据采集与报告文件设计制作的技术规程   总被引:1,自引:0,他引:1  
临床试验数据采集与报告文件的设计和制作对保证试验数据的质量与完整性至关重要。参照临床试验数据管理规范 (GCP)并结合具体实践经验制订本规程。设计规程包括与方案设计同步、文件格式、问题和提示、冗余数据、数据记录指南、标准化、版本管理与培训 ;印制规程包括审批、印制说明书以及厂商选择。  相似文献   
92.
临床试验的数据和安全监察   总被引:2,自引:2,他引:2  
临床试验数据和安全监察的目的是保证受试者的安全 ,数据的有效性 ,以及当明显的受益或风险被证实时 ,或试验不可能成功获得结论时 ,适时中止试验。所有的临床试验都应制定数据和安全监察计划 ;必要时需要建立数据和安全监察委员会。数据和安全监察的方法和强度应该与临床试验的风险以及试验规模和复杂程度相当。监察范围涉及试验实施的质量 ,以及安全性和有效性的数据。监察类型包括对试验主要结局指标等监察项目进行连续地累积性评估和中期分析。  相似文献   
93.
为规范临床试验数据管理,简化程序并减少数据统计分析过程中的错误来源,我们编制了一些特定的SAS宏程序,可以直接输出临床试验正态分布的定量指标统计分析报表。  相似文献   
94.
Regional healthcare platforms collect clinical data from hospitals in specific areas for the purpose of healthcare management. It is a common requirement to reuse the data for clinical research. However, we have to face challenges like the inconsistence of terminology in electronic health records (EHR) and the complexities in data quality and data formats in regional healthcare platform. In this paper, we propose methodology and process on constructing large scale cohorts which forms the basis of causality and comparative effectiveness relationship in epidemiology. We firstly constructed a Chinese terminology knowledge graph to deal with the diversity of vocabularies on regional platform. Secondly, we built special disease case repositories (i.e., heart failure repository) that utilize the graph to search the related patients and to normalize the data. Based on the requirements of the clinical research which aimed to explore the effectiveness of taking statin on 180-days readmission in patients with heart failure, we built a large-scale retrospective cohort with 29647 cases of heart failure patients from the heart failure repository. After the propensity score matching, the study group (n=6346) and the control group (n=6346) with parallel clinical characteristics were acquired. Logistic regression analysis showed that taking statins had a negative correlation with 180-days readmission in heart failure patients. This paper presents the workflow and application example of big data mining based on regional EHR data.  相似文献   
95.
我院作为新型冠状病毒肺炎患者收治的定点医院,积累了大量新型冠状病毒肺炎患者的医疗数据.为有效利用这些数据为临床关于新型冠状病毒肺炎科研攻关服务,我院自主研发基于新型冠状病毒肺炎的科研数据平台.利用ETL工具KETTLE整合新型冠状病毒肺炎患者的门诊和住院数据,跨平台采集和清洗HIS、电子病历、LIS和PACS等业务系统...  相似文献   
96.
The study aimed to evaluate the clinical significance of thyroid hormone-responsive (THRSP) and explore its relevant pathways in thyroid carcinoma (THCA).The gene expression data of THRSP were obtained and the prognostic significance of THRSP in THCA was analyzed through various bioinformatics databases. Then, the factors influencing THRSP mRNA expression were explored, and the function of THRSP in predicting the lymph node metastasis (LNM) stage was determined. We further performed the enrichment analysis and constructed a protein–protein interaction (PPI) network to examine potential regulatory pathways associated with THRSP.THRSP gene expression was significantly increased in THCA compared with the normal tissues. High THRSP mRNA expression had a favorable overall survival (OS) in THCA patients (P < .05). Additionally, the mRNA expression of THRSP was related to stage, histological subtype, and methylation among THCA patients (all P < .05). Besides, THRSP served as a potent predictor in discriminating the LNM stage of thyroid cancer patients. According to Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene set enrichment analysis (GSEA) on THRSP-associated genes, THRSP was positively related to metabolic pathways.The upregulation of THRSP predicted a good OS in THCA patients. Furthermore, THRSP might inhibit THCA progression through positive regulation of metabolism-associated pathways.  相似文献   
97.
目的:为提高超声诊断设备数据传输的实时性和准确性,设计一种高频超声射频回波信号高速数据传输系统.方法:该系统基于现场可编程门阵列(field programmable gate array,FPGA)和单阵元高频宽带换能器设计,由FPGA控制处理模块、超声探头模块、射频回波信号处理模块、USB传输模块以及上位机组成.采...  相似文献   
98.
Current public health advice is that high ultraviolet radiation (UVR) exposure is the primary cause of Malignant Melanoma of skin (CMM), however, despite the use of sun-blocking products incidence of melanoma is increasing. To investigate the UVR influence on CMM incidence worldwide WHO, United Nations, World Bank databases and literature provided 182 country-specific melanoma incidence estimates, daily UVR levels, skin colour (EEL), socioeconomic status (GDP PPP), magnitude of reduced natural selection (Ibs), ageing, urbanization, percentage of European descendants (Eu%), and depigmentation (blonde hair colour), for parametric and non-parametric correlations, multivariate regressions and analyses of variance. Worldwide, UVR levels showed negative correlation with melanoma incidence (“rho” = −0.515, p < 0.001), remaining significant and negative in parametric partial correlation (r = −0.513, p < 0.001) with other variables kept constant. After standardising melanoma incidence for Eu%, melanoma correlation with UVR disappeared completely (“rho” = 0.004, p = 0.967, n = 127). The results question classical views that UVR causes melanoma. No correlation between UVR level and melanoma incidence was present when Eu% (depigmented or light skin type) was kept statistically constant, even after adjusting for other known variables. Countries with lower UVR levels and more Eu% (depigmented or light skin people) have higher melanoma incidence. Critically, this means that individual genetic low skin pigmentation factors predict melanoma risk regardless of UVR exposure levels, and even at low-UVR levels.  相似文献   
99.
Background:The normative data set in authomated perimetry is predominantly of non-Indian origin and hence may not be an accurate basis for visual field analysis in Indian population. This video describes an attempt to create a native normative dataset for automated perimetry, which can then be fed in our machines and be used as the normative database.Purpose:To formulate normative data and to increase domain knowledge of normative values for automated perimetry in Indian population of different age groups.Synopsis:Cross-sectional study conducted on patients receiving outpatient care in a span of 3 years, which included 6586 healthy normal patients (13172 eyes) with vision 6/6 unaided or after refractive correction. The patients were tested with 30-2 SITA FAST threshold algorithm on Humphrey Field Analyzer Model no: 745i. Normative data was calculated on basis of age group ranging from 19-75 years categorized to every decade. Normal values were formulated on basis of perimetry performed on normal patients.Highlights:Our work on creating a native normative dataset may add value as well as increase the accuracy of perimetry analysis in Indian eyes.Online Video Link: https://youtu.be/jqgC2Tn7HIg  相似文献   
100.
BackgroundSocial media is now a common context wherein people express their feelings in real time. These platforms are increasingly showing their potential to detect the mental health status of the population. Suicide prevention is a global health priority and efforts toward early detection are starting to develop, although there is a need for more robust research.ObjectiveWe aimed to explore the emotional content of Twitter posts in Spanish and their relationships with severity of the risk of suicide at the time of writing the tweet.MethodsTweets containing a specific lexicon relating to suicide were filtered through Twitter''s public application programming interface. Expert psychologists were trained to independently evaluate these tweets. Each tweet was evaluated by 3 experts. Tweets were filtered by experts according to their relevance to the risk of suicide. In the tweets, the experts evaluated: (1) the severity of the general risk of suicide and the risk of suicide at the time of writing the tweet (2) the emotional valence and intensity of 5 basic emotions; (3) relevant personality traits; and (4) other relevant risk variables such as helplessness, desire to escape, perceived social support, and intensity of suicidal ideation. Correlation and multivariate analyses were performed.ResultsOf 2509 tweets, 8.61% (n=216) were considered to indicate suicidality by most experts. Severity of the risk of suicide at the time was correlated with sadness (ρ=0.266; P<.001), joy (ρ=–0.234; P=.001), general risk (ρ=0.908; P<.001), and intensity of suicidal ideation (ρ=0.766; P<.001). The severity of risk at the time of the tweet was significantly higher in people who expressed feelings of defeat and rejection (P=.003), a desire to escape (P<.001), a lack of social support (P=.03), helplessness (P=.001), and daily recurrent thoughts (P=.007). In the multivariate analysis, the intensity of suicide ideation was a predictor for the severity of suicidal risk at the time (β=0.311; P=.001), as well as being a predictor for fear (β=–0.009; P=.01) and emotional valence (β=0.007; P=.009). The model explained 75% of the variance.ConclusionsThese findings suggest that it is possible to identify emotional content and other risk factors in suicidal tweets with a Spanish sample. Emotional analysis and, in particular, the detection of emotional variations may be key for real-time suicide prevention through social media.  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