全文获取类型
收费全文 | 187701篇 |
免费 | 8082篇 |
国内免费 | 462篇 |
专业分类
耳鼻咽喉 | 2898篇 |
儿科学 | 5623篇 |
妇产科学 | 4602篇 |
基础医学 | 25879篇 |
口腔科学 | 6056篇 |
临床医学 | 11345篇 |
内科学 | 44148篇 |
皮肤病学 | 5760篇 |
神经病学 | 14925篇 |
特种医学 | 4317篇 |
外国民族医学 | 3篇 |
外科学 | 22778篇 |
综合类 | 921篇 |
一般理论 | 50篇 |
预防医学 | 20077篇 |
眼科学 | 4346篇 |
药学 | 13861篇 |
1篇 | |
中国医学 | 802篇 |
肿瘤学 | 7853篇 |
出版年
2023年 | 1061篇 |
2022年 | 840篇 |
2021年 | 3373篇 |
2020年 | 1749篇 |
2019年 | 3776篇 |
2018年 | 6494篇 |
2017年 | 3887篇 |
2016年 | 3669篇 |
2015年 | 4150篇 |
2014年 | 4718篇 |
2013年 | 7319篇 |
2012年 | 12535篇 |
2011年 | 13173篇 |
2010年 | 6648篇 |
2009年 | 4733篇 |
2008年 | 10705篇 |
2007年 | 11571篇 |
2006年 | 10836篇 |
2005年 | 10654篇 |
2004年 | 9736篇 |
2003年 | 9208篇 |
2002年 | 8702篇 |
2001年 | 5877篇 |
2000年 | 6583篇 |
1999年 | 5044篇 |
1998年 | 889篇 |
1997年 | 590篇 |
1996年 | 605篇 |
1992年 | 2245篇 |
1991年 | 1978篇 |
1990年 | 1797篇 |
1989年 | 1568篇 |
1988年 | 1401篇 |
1987年 | 1392篇 |
1986年 | 1345篇 |
1985年 | 1224篇 |
1984年 | 888篇 |
1983年 | 712篇 |
1979年 | 885篇 |
1978年 | 532篇 |
1976年 | 505篇 |
1975年 | 595篇 |
1974年 | 804篇 |
1973年 | 795篇 |
1972年 | 691篇 |
1971年 | 672篇 |
1970年 | 723篇 |
1969年 | 683篇 |
1968年 | 658篇 |
1967年 | 593篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Rosario Fernández-Plata Rogelio Pérez-Padilla Rodrigo Del Río-Hidalgo Cecilia García-Sancho Laura Gochicoa-Rangel Christian Rodríguez-Hernández Luis Torre-Bouscoulet David Martínez-Briseño 《Archivos de bronconeumología》2019,55(10):513-518
IntroductionPeople with Down syndrome (DS) have high respiratory morbidity, evaluating their respiratory health with standardized, objective tests is desirable. Thus, the objective of this study was to evaluate the technical quality of Pulmonary Function Tests (PFTs) to determine which ones are most suitable for this population.MethodsParticipants included children, teenagers and adults with DS, 5 years of age or older (n = 302). The technical quality of the impulse oscillometry system (IOS), forced spirometry, lung-diffusing capacity for carbon monoxide (DLCO), and 6-min walk test (6MWT) were analyzed by age group. Capnography and pulse oximetry were included in the study. Technical quality was determined on the basis of current international PFTs standards.ResultsFifty-one percent of participants were males. A total of 184 participants (71%) who completed the IOS fulfilled the quality criteria, while 210 (70%) completed the 6MWT. Performance on forced spirometry and DLCO was poor. All pulse oximetries and 96% percent heart rates obtained had good quality, but exhaled carbon dioxide (PetCO2) and respiratory rate (RR) showed deficient repeatability.ConclusionsIOS appears to be the most reliable instrument for evaluating lung mechanics in individuals with DS. 相似文献
82.
María Cabrerizo Gloria Trallero María José Pena Amaia Cilla Gregoria Megias Carmen Mu?oz-Almagro Eva Del Amo Diana Roda Ana Isabel Mensalvas Antonio Moreno-Docón Juan García-Costa Nuria Rabella Manuel Ome?aca María Pilar Romero Sara Sanbonmatsu-Gámez Mercedes Pérez-Ruiz María José Santos-Mu?oz Cristina Calvo And the study group of “Enterovirus parechovirus infections in children under ?years-old Spain” PI- 《European journal of pediatrics》2015,174(11):1511-1516
83.
Carlos A. ávila-Orta Zoe V. Qui?ones-Jurado Miguel A. Waldo-Mendoza Erika A. Rivera-Paz Víctor J. Cruz-Delgado José M. Mata-Padilla Pablo González-Morones Ronald F. Ziolo 《Materials》2015,8(11):7900-7912
Isotactic polypropylenes (iPP) with different melt flow indexes (MFI) were used to fabricate nanocomposites (NCs) with 10 wt % loadings of multi-wall carbon nanotubes (MWCNTs) using ultrasound-assisted extrusion methods to determine their effect on the morphology, melt flow, and electrical properties of the NCs. Three different types of iPPs were used with MFIs of 2.5, 34 and 1200 g/10 min. Four different NC fabrication methods based on melt extrusion were used. In the first method melt extrusion fabrication without ultrasound assistance was used. In the second and third methods, an ultrasound probe attached to a hot chamber located at the exit of the die was used to subject the sample to fixed frequency and variable frequency, respectively. The fourth method is similar to the first method, with the difference being that the carbon nanotubes were treated in a fluidized air-bed with an ultrasound probe before being used in the fabrication of the NCs with no ultrasound assistance during extrusion. The samples were characterized by MFI, Optical microscopy (OM), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), electrical surface resistivity, and electric charge. MFI decreases in all cases with addition of MWCNTs with the largest decrease observed for samples with the highest MFI. The surface resistivity, which ranged from 1013 to 105 Ω/sq, and electric charge, were observed to depend on the ultrasound-assisted fabrication method as well as on the melt flow index of the iPP. A relationship between agglomerate size and area ratio with electric charge was found. Several trends in the overall data were identified and are discussed in terms of MFI and the different fabrication methods. 相似文献
84.
Objective
To explore from a gender perspective the association with subjective health of the interaction between education and household arrangements within the framework of social determinants of health placed at the micro and mezzo levels.Methods
The data comes from the Spanish sample of the European Union Statistics on Income and Living Conditions for 2014. Independent logistic regression models for men and women were run to analyze the association with subjective health of the interaction between education and household arrangements. An additive model was run to assess possible advantages over the interaction approach.Results
The interaction models show a lower or even no significant effect on health of household arrangements usually negatively associated with health among individuals with high education, displaying specific patterns according to sex.Conclusions
Health profiles of women and men are more precisely drawn if both social determinants of health are combined. Among the women, the important role was confirmed of both social determinants of health in understanding their health inequalities. Among the men, mainly those with low educational achievement, the interaction revealed that the household was a more meaningful social determinant of health. This could enable the definition of more efficient public policies to reduce health and gender inequalities. 相似文献85.
86.
Emmi Helle Aldo Córdova-Palomera Tiina Ojala Priyanka Saha Praneetha Potiny Stefan Gustafsson Erik Ingelsson Michael Bamshad Deborah Nickerson Jessica X. Chong University of Washington Center for Mendelian Genomics Euan Ashley James R. Priest 《Genetic epidemiology》2019,43(2):215-226
Loss of function variants in NOTCH1 cause left ventricular outflow tract obstructive defects (LVOTO). However, the risk conferred by rare and noncoding variants in NOTCH1 for LVOTO remains largely uncharacterized. In a cohort of 49 families affected by hypoplastic left heart syndrome, a severe form of LVOTO, we discovered predicted loss of function NOTCH1 variants in 6% of individuals. Rare or low-frequency missense variants were found in 16% of families. To make a quantitative estimate of the genetic risk posed by variants in NOTCH1 for LVOTO, we studied associations of 400 coding and noncoding variants in NOTCH1 in 1,085 cases and 332,788 controls from the UK Biobank. Two rare intronic variants in strong linkage disequilibrium displayed significant association with risk for LVOTO amongst European-ancestry individuals. This result was replicated in an independent analysis of 210 cases and 68,762 controls of non-European and mixed ancestry. In conclusion, carrying rare predicted loss of function variants in NOTCH1 confer significant risk for LVOTO. In addition, the two intronic variants seem to be associated with an increased risk for these defects. Our approach demonstrates the utility of population-based data sets in quantifying the specific risk of individual variants for disease-related phenotypes. 相似文献
87.
88.
Luana Lopes Padilha Elcio Oliveira Vianna Andressa Talícia Machado Vale Joelma Ximenes Prado Teixeira Nascimento Antônio Augusto Moura da Silva Cecilia Claudia Costa Ribeiro 《Pediatric allergy and immunology》2020,31(5):480-488
Studies on the exposure of children to sugar-sweetened beverages (SSBs) at an early age may contribute to better understand the common causes and the temporal order of the relationships between obesity and asthma in early childhood. The objective of this study was to estimate the association between SSB and child asthma traits in the 2nd year of life, modeling direct and indirect pathways mediated by the highest BMI-z of the child and allergic inflammation. Data from the BRISA cohort, São Luís-MA, Brazil (n = 1140), were obtained from the baseline and from the follow-up performed at the 2nd year of life. The main explanatory variable was the calories from added sugars in SSBs as a percentage of the total daily energy intake. The outcome child asthma traits was a latent variable deduced from four indicators: medical diagnosis of asthma, wheezing, emergency visit due to intense wheezing, and medical diagnosis of rhinitis. A high percentage of daily calories from sugars added to SSBs was directly associated with higher values of child asthma traits (standardized coefficient (SC = 0.073; P = .030)). High levels of eosinophils were also directly associated with child asthma traits (SC = 0.118; P = .049). No mediation pathways were observed via greater BMI-z or eosinophil counts. Therefore, early exposure of children to SSB may contribute to increased risk of childhood asthma, preceding the link between sugar consumption and overweight/obesity, not yet evident in children in the first 2 years of life. 相似文献
89.
90.
J. Rodríguez-Carrio A. Martínez-Zapico I. Cabezas-Rodríguez L. Benavente Á.I. Pérez-Álvarez P. López J.B. Cannata-Andía M. Naves-Díaz A. Suárez 《Nutrition, metabolism, and cardiovascular diseases : NMCD》2019,29(2):135-143