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   31436篇
  免费   2885篇
  国内免费   435篇
耳鼻咽喉   259篇
儿科学   917篇
妇产科学   512篇
基础医学   1884篇
口腔科学   788篇
临床医学   6338篇
内科学   3653篇
皮肤病学   324篇
神经病学   2767篇
特种医学   542篇
外国民族医学   1篇
外科学   2666篇
综合类   2557篇
一般理论   7篇
预防医学   6946篇
眼科学   157篇
药学   2815篇
  68篇
中国医学   484篇
肿瘤学   1071篇
  2024年   101篇
  2023年   759篇
  2022年   1352篇
  2021年   1653篇
  2020年   1664篇
  2019年   1724篇
  2018年   1642篇
  2017年   1453篇
  2016年   1380篇
  2015年   1198篇
  2014年   2362篇
  2013年   3100篇
  2012年   1660篇
  2011年   1842篇
  2010年   1367篇
  2009年   1389篇
  2008年   1424篇
  2007年   1346篇
  2006年   1077篇
  2005年   910篇
  2004年   748篇
  2003年   654篇
  2002年   523篇
  2001年   504篇
  2000年   417篇
  1999年   330篇
  1998年   292篇
  1997年   245篇
  1996年   241篇
  1995年   195篇
  1994年   195篇
  1993年   144篇
  1992年   123篇
  1991年   98篇
  1990年   83篇
  1989年   60篇
  1988年   56篇
  1987年   55篇
  1986年   51篇
  1985年   73篇
  1984年   60篇
  1983年   32篇
  1982年   32篇
  1981年   30篇
  1980年   28篇
  1979年   25篇
  1978年   13篇
  1977年   11篇
  1976年   11篇
  1975年   12篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Cyanobacteria are ubiquitous photosynthetic micro-organisms forming blooms and scums in surface water; among them some species can produce cyanotoxins giving rise to some concern for human health and animal life. To date, more than 65 cyanobacterial neurotoxins have been described, of which the most studied are the groups of anatoxins and saxitoxins (STXs), comprising many different variants. In freshwaters, the hepatotoxic microcystins represent the most frequently detected cyanotoxin: on this basis, it could appear that neurotoxins are less relevant, but the low frequency of detection may partially reflect an a priori choice of target analytes, the low method sensitivity and the lack of certified standards. Cyanobacterial neurotoxins target cholinergic synapses or voltage-gated ion channels, blocking skeletal and respiratory muscles, thus leading to death by respiratory failure. This review reports and analyzes the available literature data on environmental occurrence of cyanobacterial neurotoxic alkaloids, namely anatoxins and STXs, their biosynthesis, toxicology and epidemiology, derivation of guidance values and action limits. These data are used as the basis to assess the risk posed to human health, identify critical exposure scenarios and highlight the major data gaps and research needs.  相似文献   
102.
英国伦理委员会的现状与分析   总被引:1,自引:0,他引:1  
翁新愚 《中国新药杂志》2008,17(19):1724-1727
伦理委员会的主要职责是保护药物临床试验受试者的权益、安全和健康.现对英国伦理委员会的法律、法规、申请及审评程序等进行归纳分析,旨在对规范我国伦理委员会的运作具有参考借鉴作用.  相似文献   
103.
896例成人嗓音声学参数的计算机采集分析   总被引:8,自引:2,他引:6  
目的 通过研究获得有关嗓音医学的数据标准及各种嗓音疾病的特征性客观指标 ,建立嗓音临床检测系统 ,为临床诊断与治疗提供有效的参考标准和方法。方法 应用Dr.Speech(DSS)软件的先进技术 ,按卫生部(司 ) :“语音、语言测试和矫治行业标准”的研究要求 ,采集、分析上海地区成人 5 0 0例正常嗓音以及 396例临床常见嗓音疾病的病理性嗓音的声学样本。结果 正常人的各嗓音声学参数 :基频微扰、振幅微扰、声门噪声、频率颤动、共振峰等值均在DSS软件提供的正常范围内 ,而病理性嗓音声学参数超出该范围 ,并具有各不同的特点。结论 我国成人嗓音声学参数与欧美的相似 ,应用Dr.Speech软件可对各种嗓音疾病进行临床客观检测和评估  相似文献   
104.
105.
嗓音声学分析与心理听觉评价的相关性研究   总被引:3,自引:0,他引:3  
目的 :探讨嗓音声学分析参数与声嘶程度心理听觉评价之间的关系。方法 :对 178例受试者进行嗓音声学分析 ,按声嘶程度将 2 4例正常人及 15 4例病理嗓音患者分成四组 ,对各组的嗓音声学分析参数及其与声嘶程度的关系进行统计学处理。结果 :除 0级与 1级组 jitter值差异无显著性外 ,其余各参数在各组间差异均有显著性意义。NNE和 SNR为判别声嘶程度的最有意义的两个参数 ,5个参数 (jitter,shim mer,NNE,SNR,SDF0 )均与声嘶程度有良好的相关关系。结论 :嗓音声学分析参数可以较简便直观地评价声嘶程度 ,为临床诊断提供依据。  相似文献   
106.
The Serbian Food Consumption Survey among 1–9-year-old-children was conceptualized and conducted in compliance with the principles, established protocols, and guidelines of the EU Menu project between 2017 and 2021. Valid data were collected for 576 individuals (290 1–3-year-old toddlers and 276 3–9-year-old children). Regardless of age and gender category, the majority (68.80%) of children had normal weights according to the Body Mass Index-for-age classification system. The median daily energy intake was 1406.71 kcal with no differences between the settlement types. The overall median contributions of carbohydrates, protein, and fat to the total energy intake were 47.54%, 14.06%, and 37.88%, respectively. The proportions of the macronutrient intake deviated from the dietary reference values with compliance to the recommendations being particularly poor for fat and fiber. The consumption of energy-dense food groups such as meat and meat products, fat and oil, sugar, and confections was more pronounced among older children. The survey results provide a valuable insight into the nutritional status and dietary habits of toddlers and children 1–9 years old living in Serbia. They may serve as an evidence platform for public health programs, a valuable asset for decision-makers, and a reliable reference to guide nutritional policies, diet monitoring, and interventions targeting this population group in the future.  相似文献   
107.
People appear to vary in their susceptibility to lifestyle risk factors for cardiometabolic disease; determining a priori who is most sensitive may help optimize the timing, design, and delivery of preventative interventions. We aimed to ascertain a person’s degree of resilience or sensitivity to adverse lifestyle exposures and determine whether these classifications help predict cardiometabolic disease later in life; we pooled data from two population-based Swedish prospective cohort studies (n = 53,507), and we contrasted an individual’s cardiometabolic biomarker profile with the profile predicted for them given their lifestyle exposure characteristics using a quantile random forest approach. People who were classed as ‘sensitive’ to hypertension- and dyslipidemia-related lifestyle exposures were at higher risk of developing cardiovascular disease (CVD, hazards ratio 1.6 (95% CI: 1.3, 1.91)), compared with the general population. No differences were observed for type 2 diabetes (T2D) risk. Here, we report a novel approach to identify individuals who are especially sensitive to adverse lifestyle exposures and who are at higher risk of subsequent cardiovascular events. Early preventive interventions may be needed in this subgroup.  相似文献   
108.
BackgroundCardiovascular risk factors and comorbidities are highly prevalent among COVID‐19 patients and are associated with worse outcomes.HypothesisWe therefore investigated if established cardiovascular risk assessment models could efficiently predict adverse outcomes in COVID‐19. Furthermore, we aimed to generate novel risk scores including various cardiovascular parameters for prediction of short‐ and midterm outcomes in COVID‐19.MethodsWe included 441 consecutive patients diagnosed with SARS‐CoV‐2 infection. Patients were followed‐up for 30 days after the hospital admission for all‐cause mortality (ACM), venous/arterial thromboembolism, and mechanical ventilation. We further followed up the patients for post‐COVID‐19 syndrome for 6 months and occurrence of myocarditis, heart failure, acute coronary syndrome (ACS), and rhythm events in a 12‐month follow‐up. Discrimination performance of DAPT, GRACE 2.0, PARIS‐CTE, PREDICT‐STABLE, CHA2‐DS2‐VASc, HAS‐BLED, PARIS‐MB, PRECISE‐DAPT scores for selected endpoints was evaluated by ROC‐analysis.ResultsOut of established risk assessment models, GRACE 2.0 score performed best in predicting combined endpoint and ACM. Risk assessment models including age, cardiovascular risk factors, echocardiographic parameters, and biomarkers, were generated and could successfully predict the combined endpoint, ACM, venous/arterial thromboembolism, need for mechanical ventilation, myocarditis, ACS, heart failure, and rhythm events. Prediction of post‐COVID‐19 syndrome was poor.ConclusionRisk assessment models including age, laboratory parameters, cardiovascular risk factors, and echocardiographic parameters showed good discrimination performance for adverse short‐ and midterm outcomes in COVID‐19 and outweighed discrimination performance of established cardiovascular risk assessment models.  相似文献   
109.
Current controversies regarding pain assessment in neonates   总被引:3,自引:0,他引:3  
Although over 40 methods of pain assessment in infants are available for use in clinical practice, unrecognized and under-treated pain remains one of the most commonly reported problems within the Neonatal Intensive Care Units. A number of factors have been found to account for differences in the robustness of the pain response in neonates of varying gestational ages. Discrepancies between behavioral and physiological pain indicators have also been reported. With newer technologies, there is an opportunity not only to verify infant pain perception, but these tools may allow an identification of which of the observed indicators are most sensitive in particular clinical situations. The current controversies regarding pain assessment in preterm and term infants are reviewed to define the most important issues and to develop a dialogue for future directions.  相似文献   
110.
Objective The objective of the following study is to report the experience acquired from 24 percutaneous fetal surgeries for cavity drainage using epidural catheter instead of the commercially available catheter. Methods Twenty-four percutaneous fetal surgeries for cavity drainage were performed, due to the following anomalies: 13 cases of lower urinary tract obstruction, nine cases of pleural effusion, and two cases of pulmonary cystic adenomatoid malformation type I. In order to verify that catheter adequacy, technical and obstetric complications derived from its use were assessed. Technical complications were difficulty in inserting the catheter and/or its functionality; and obstetric complications were the presence of bleeding, amniotic infection, preterm labor or premature rupture of membranes. Results The technical complications were the following: difficulty in passing the catheter through epidural needle in one case; one case of catheter drawn back with the needle; two cases of catheter dislodgment; and four cases of non-functionality of the catheter. Among the obstetric complications, there was only one case of preterm labor, and except from one fetus with chromosomal pathology, all the other 23 newborns were alive after 1 week. Conclusions The use of the epidural catheter can be seen as a viable alternative to percutaneous surgeries of fetal cavity shunting, due to its low cost and similar complications to the use of the conventional catheter.  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