全文获取类型
收费全文 | 27360篇 |
免费 | 2652篇 |
国内免费 | 447篇 |
专业分类
耳鼻咽喉 | 273篇 |
儿科学 | 705篇 |
妇产科学 | 383篇 |
基础医学 | 1356篇 |
口腔科学 | 790篇 |
临床医学 | 5338篇 |
内科学 | 3370篇 |
皮肤病学 | 261篇 |
神经病学 | 2130篇 |
特种医学 | 610篇 |
外科学 | 3135篇 |
综合类 | 2048篇 |
一般理论 | 6篇 |
预防医学 | 5465篇 |
眼科学 | 155篇 |
药学 | 2634篇 |
68篇 | |
中国医学 | 456篇 |
肿瘤学 | 1276篇 |
出版年
2024年 | 91篇 |
2023年 | 685篇 |
2022年 | 1194篇 |
2021年 | 1484篇 |
2020年 | 1497篇 |
2019年 | 1516篇 |
2018年 | 1465篇 |
2017年 | 1338篇 |
2016年 | 1274篇 |
2015年 | 1109篇 |
2014年 | 2072篇 |
2013年 | 2692篇 |
2012年 | 1442篇 |
2011年 | 1595篇 |
2010年 | 1163篇 |
2009年 | 1190篇 |
2008年 | 1187篇 |
2007年 | 1135篇 |
2006年 | 908篇 |
2005年 | 809篇 |
2004年 | 669篇 |
2003年 | 555篇 |
2002年 | 465篇 |
2001年 | 453篇 |
2000年 | 358篇 |
1999年 | 288篇 |
1998年 | 264篇 |
1997年 | 216篇 |
1996年 | 214篇 |
1995年 | 164篇 |
1994年 | 164篇 |
1993年 | 120篇 |
1992年 | 114篇 |
1991年 | 86篇 |
1990年 | 71篇 |
1989年 | 61篇 |
1988年 | 44篇 |
1987年 | 50篇 |
1986年 | 40篇 |
1985年 | 48篇 |
1984年 | 37篇 |
1983年 | 19篇 |
1982年 | 24篇 |
1981年 | 22篇 |
1980年 | 18篇 |
1979年 | 16篇 |
1978年 | 10篇 |
1976年 | 4篇 |
1975年 | 9篇 |
1974年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Deoxynivalenol (DON) remains one of the most concerning mycotoxins produced by the Fusarium genus due to the wide occurrence in highly consumed cereal-based food and its associated toxicological effects. Previous studies conducted in Spain and other European countries suggested that some vulnerable groups such as children could be exceeding the tolerable daily intakes. Thus, the aim of this study was to conduct a comprehensive and updated dietary exposure assessment study in Spain, with a specific analysis in the region of Catalonia. Cereal-based food samples collected during 2019 were analysed using liquid chromatography coupled to tandem mass spectrometry for multi-mycotoxin detection including DON and its main metabolites and derivatives. Consumption data were gathered from the nation-wide food surveys ENALIA and ENALIA2 conducted in Spain, and a specific survey conducted in Catalonia. The data were combined using deterministic and semi-parametric probabilistic methods. The results showed that DON was widely present in cereal-based food highly consumed in Spain and the Catalonia region. Exposure to DON among the adult population was globally low; however, among infants aged 3–9 years, it resulted in the median of 192 ng/kg body weight/day and the 95th percentiles of 604 ng/kg body weight/day, that would exceed the most conservative safety threshold for infants. Bread and pasta were the main contributing foodstuffs to the global exposure to DON, even among infants; thus, those foods should be considered a priority for food control or to develop strategies to reduce the exposure. In any case, further toxicological and epidemiological studies are required in order to refine the safety thresholds accounting for the sensitivity of the infant population. 相似文献
92.
Emanuela Testai Simona Scardala Susanna Vichi Franca M. Buratti Enzo Funari 《Critical reviews in toxicology》2016,46(5):385-419
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
93.
英国伦理委员会的现状与分析 总被引:1,自引:0,他引:1
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
94.
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
95.
96.
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
97.
Milica Zekovi Jelena Mileevi Marija Taki Marija Knez Ivana arac Agnes Kadvan Mirjana Gurinovi Marija Glibeti 《Nutrients》2022,14(15)
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
98.
Predicting Sensitivity to Adverse Lifestyle Risk Factors for Cardiometabolic Morbidity and Mortality
Hugo Pomares-Millan Alaitz Poveda Naemieh Atabaki-Pasdar Ingegerd Johansson Jonas Bjrk Mattias Ohlsson Giuseppe N. Giordano Paul W. Franks 《Nutrients》2022,14(15)
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
99.
Monika Zdanyte Peter Martus Jeremy Nestele Alexander Bild Lars Mizera Andreas Glatthaar lvaro Petersen Uribe Frederic Emschermann JessicaKristin Henes Tobias Geisler Karin Müller Meinrad Gawaz Dominik Rath 《Clinical cardiology》2022,45(9):943
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
100.