全文获取类型
收费全文 | 1102061篇 |
免费 | 70915篇 |
国内免费 | 1767篇 |
专业分类
耳鼻咽喉 | 15423篇 |
儿科学 | 30953篇 |
妇产科学 | 28519篇 |
基础医学 | 155010篇 |
口腔科学 | 33397篇 |
临床医学 | 93940篇 |
内科学 | 213550篇 |
皮肤病学 | 23241篇 |
神经病学 | 82334篇 |
特种医学 | 46448篇 |
外国民族医学 | 176篇 |
外科学 | 177597篇 |
综合类 | 19040篇 |
现状与发展 | 1篇 |
一般理论 | 235篇 |
预防医学 | 76362篇 |
眼科学 | 25163篇 |
药学 | 84532篇 |
5篇 | |
中国医学 | 2278篇 |
肿瘤学 | 66539篇 |
出版年
2018年 | 12247篇 |
2017年 | 10694篇 |
2016年 | 10729篇 |
2015年 | 13371篇 |
2014年 | 15910篇 |
2013年 | 20545篇 |
2012年 | 33067篇 |
2011年 | 29173篇 |
2010年 | 16743篇 |
2009年 | 17734篇 |
2008年 | 26365篇 |
2007年 | 28114篇 |
2006年 | 29103篇 |
2005年 | 35847篇 |
2004年 | 36437篇 |
2003年 | 31229篇 |
2002年 | 26186篇 |
2001年 | 58043篇 |
2000年 | 57908篇 |
1999年 | 51529篇 |
1998年 | 11167篇 |
1997年 | 9678篇 |
1996年 | 9878篇 |
1995年 | 9229篇 |
1994年 | 8549篇 |
1993年 | 7809篇 |
1992年 | 41052篇 |
1991年 | 39774篇 |
1990年 | 38833篇 |
1989年 | 37681篇 |
1988年 | 34443篇 |
1987年 | 33447篇 |
1986年 | 31313篇 |
1985年 | 29623篇 |
1984年 | 20872篇 |
1983年 | 17615篇 |
1982年 | 8645篇 |
1979年 | 19131篇 |
1978年 | 12692篇 |
1977年 | 10626篇 |
1976年 | 9248篇 |
1975年 | 10874篇 |
1974年 | 13289篇 |
1973年 | 12360篇 |
1972年 | 11874篇 |
1971年 | 11381篇 |
1970年 | 10777篇 |
1969年 | 10175篇 |
1968年 | 9264篇 |
1967年 | 8506篇 |
排序方式: 共有10000条查询结果,搜索用时 18 毫秒
141.
142.
C. Lukannek S. Shaefi K. Platzbecker D. Raub P. Santer S. Nabel H.S. Lecamwasam T.T. Houle M. Eikermann 《Anaesthesia》2019,74(9):1165-1174
Postoperative pulmonary complications are associated with an increase in mortality, morbidity and healthcare utilisation. The Agency for Healthcare Research and Quality recommends risk assessment for postoperative respiratory complications in patients undergoing surgery. In this hospital registry study of adult patients undergoing non-cardiac surgery between 2005 and 2017 at two independent healthcare networks, a prediction instrument for early postoperative tracheal re-intubation was developed and externally validated. This was based on the development of the Score for Prediction Of Postoperative Respiratory Complications. For predictor selection, stepwise backward logistic regression and bootstrap resampling were applied. Development and validation cohorts were represented by 90,893 patients at Partners Healthcare and 67,046 patients at Beth Israel Deaconess Medical Center, of whom 699 (0.8%) and 587 (0.9%) patients, respectively, had their tracheas re-intubated. In addition to five pre-operative predictors identified in the Score for Prediction Of Postoperative Respiratory Complications, the final model included seven additional intra-operative predictors: early post-tracheal intubation desaturation; prolonged duration of surgery; high fraction of inspired oxygen; high vasopressor dose; blood transfusion; the absence of volatile anaesthetic use; and the absence of lung-protective ventilation. The area under the receiver operating characteristic curve for the new score was significantly greater than that of the original Score for Prediction Of Postoperative Respiratory Complications (0.84 [95%CI 0.82–0.85] vs. 0.76 [95%CI 0.75–0.78], respectively; p < 0.001). This may allow clinicians to develop and implement strategies to decrease the risk of early postoperative tracheal re-intubation. 相似文献
143.
144.
Schizophrenia is a chronic and severe psychiatric disorder that has profound impact on an individual’s life and on society. Thus, developing more effective therapeutic interventions is essential. Over the past quarter‐century, an abundance of evidence from pharmacologic challenges, post‐mortem studies, brain imaging, and genetic studies supports the role of glutamatergic dysregulation in the pathophysiology of schizophrenia, and the results of recent randomized clinical trials based on this evidence have yielded promising results. In this article, we review the evidence that alterations in glutamatergic neurotransmission, especially focusing on the N‐methyl‐d ‐aspartate receptor (NMDAR) function, may be a critical causative feature of schizophrenia, how this contributes to pathologic circuit function in the brain, and how these insights are revealing whole new avenues for treatment development that could reduce treatment‐resistant symptoms, which account for persistent disability. 相似文献
145.
This paper reviews the published literature on a group of developmental disorders of the retina and retinal pigment epithelium which result in focal abnormalities in one or both eyes. They are often asymptomatic, found on routine examination and are generally non-progressive. Some are associated with other systemic abnormalities.Subject terms: Retinal diseases, Eye abnormalities 相似文献
146.
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
147.
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
148.
Joseph D. Westaby Susanna T. E. Cooper Khari A. Edwards Robert H. Anderson Mary N. Sheppard 《Clinical anatomy (New York, N.Y.)》2020,33(3):394-404
Congenital heart disease is a rare but important finding in adults who experience sudden death. Examination of the congenitally malformed heart has historically been considered esoteric and best left to those with expertise. The Cardiac Risk in the Young cardiovascular pathology laboratory based at St George's University of London has now received over 6,000 cases. Of these, 21 congenitally malformed hearts were retained for research and educational purposes. Hearts were assessed using sequential segmental analysis, and causes of death were adjudicated based on thorough macroscopic examination and histology. Congenital malformations that were encountered included atrial septal defects, ventricular septal defects, tetralogy of Fallot, and transposition of the great arteries in both its regular and congenitally corrected variants. Findings also included hearts with mirror-imaged and isomeric atrial appendages. Direct causes of death included myocardial fibrosis, pulmonary hypertension, and hemorrhage. A small but notable proportion did not reveal a substrate for arrhythmia, raising the question of whether the terminal event was due to the congenital heart disease itself, or an underlying channelopathy. Here, we demonstrate the value of simple sequential segmental analysis in describing and categorizing the cases, with the concept of the “morphological method” serving to identify the distinguishing features of the cardiac components. Clin. Anat. 33:394–404, 2020. © 2019 Wiley Periodicals, Inc. 相似文献
149.
150.