全文获取类型
收费全文 | 25682篇 |
免费 | 1229篇 |
国内免费 | 86篇 |
专业分类
耳鼻咽喉 | 314篇 |
儿科学 | 645篇 |
妇产科学 | 635篇 |
基础医学 | 3368篇 |
口腔科学 | 1608篇 |
临床医学 | 1880篇 |
内科学 | 6172篇 |
皮肤病学 | 521篇 |
神经病学 | 1935篇 |
特种医学 | 548篇 |
外科学 | 2904篇 |
综合类 | 125篇 |
一般理论 | 13篇 |
预防医学 | 3066篇 |
眼科学 | 387篇 |
药学 | 1724篇 |
1篇 | |
中国医学 | 144篇 |
肿瘤学 | 1007篇 |
出版年
2023年 | 229篇 |
2022年 | 153篇 |
2021年 | 552篇 |
2020年 | 345篇 |
2019年 | 611篇 |
2018年 | 1067篇 |
2017年 | 638篇 |
2016年 | 655篇 |
2015年 | 798篇 |
2014年 | 844篇 |
2013年 | 1149篇 |
2012年 | 2065篇 |
2011年 | 2270篇 |
2010年 | 1026篇 |
2009年 | 695篇 |
2008年 | 1723篇 |
2007年 | 1834篇 |
2006年 | 1624篇 |
2005年 | 1576篇 |
2004年 | 1390篇 |
2003年 | 1284篇 |
2002年 | 1181篇 |
2001年 | 448篇 |
2000年 | 495篇 |
1999年 | 366篇 |
1998年 | 106篇 |
1997年 | 50篇 |
1996年 | 51篇 |
1995年 | 45篇 |
1994年 | 36篇 |
1993年 | 43篇 |
1992年 | 221篇 |
1991年 | 158篇 |
1990年 | 136篇 |
1989年 | 118篇 |
1988年 | 103篇 |
1987年 | 101篇 |
1986年 | 91篇 |
1985年 | 72篇 |
1984年 | 56篇 |
1983年 | 56篇 |
1979年 | 32篇 |
1975年 | 38篇 |
1974年 | 50篇 |
1973年 | 29篇 |
1971年 | 34篇 |
1970年 | 36篇 |
1969年 | 32篇 |
1968年 | 38篇 |
1967年 | 28篇 |
排序方式: 共有10000条查询结果,搜索用时 93 毫秒
11.
Adilson Cunha Ferreira Edward Araujo Júnior Wellington P. Martins João Francisco Jordão Antônio Hélio Oliani Simon E. Meagher 《The journal of maternal-fetal & neonatal medicine》2015,28(14):1706-1710
Objective: To assess the quality of images and video clips of fetal central nervous (CNS) structures obtained by ultrasound and transmitted via tele-ultrasound from Brazil to Australia.Methods: In this cross-sectional study, 15 normal singleton pregnant women between 20 and 26 weeks were selected. Fetal CNS structures were obtained by images and video clips. The exams were transmitted in real-time using a broadband internet and an inexpensive video streaming device. Four blinded examiners evaluated the quality of the exams using the Likert scale. We calculated the mean, standard deviation, mean difference, and p values were obtained from paired t tests.Results: The quality of the original video clips was slightly better than that observed by the transmitted video clips; mean difference considering all observers = 0.23 points. In 47/60 comparisons (78.3%; 95% CI?=?66.4–86.9%) the quality of the video clips were judged to be the same. In 182/240 still images (75.8%; 95% CI?=?70.0–80.8%) the scores of transmitted image were considered the same as the original.Conclusion: We demonstrated that long distance tele-ultrasound transmission of fetal CNS structures using an inexpensive video streaming device provided images of subjective good quality. 相似文献
12.
13.
Camila Padilha Barbosa Rosalie Barreto Belian Cláudia Marina Tavares de Araújo 《Jornal de pediatria》2021,97(1):80-87
ObjectiveTo present, the process of development and evaluation of an educational software on the Child Health Handbook proposed for the continuing education of primary care nurses and physicians.MethodsQuantitative study of methodological development. For software development, the following steps were followed: definition of objectives; determination of the target audience; choice of pedagogical and theoretical reference for content; content selection and structuring; software development and evaluation by experts (five nurses and four physicians). All responded to an instrument that included four domains: pedagogical; content; functionality; system presentation and usability. The evaluation criteria were arranged on a Likert-type scale. The percentage of agreement and Content Validity Index were used for the quantitative analysis of the degree of agreement, considering a Content Validity Index cutoff point equal to 0.80.ResultsThe overall agreement index, calculated by the arithmetic mean of the Contents Validity Index of the evaluated domains, was 0.96, with scores ranging from 0.90 to 1.00. The average percentage of agreement of the experts per domain was 92.86%, with lower agreement in the content (80.95%), presentation, and usability (90.48%) domains. 100% of percentage of agreement was observed in the pedagogical and functionality domains among the evaluated specialists.ConclusionThe percentage of agreement, Content Validity Index and overall agreement index of the Child Health Handbook educational software in the context of primary care disclosed the software adequacy as an educational resource for continuing education of primary care nurses and physicians. Considering the assessed dimensions, it can also be used by other health professionals and undergraduate students. 相似文献
14.
Phenotypic and genetic features of enteropathogenic Escherichia coli isolates from diarrheal children in the Ribeirão Preto metropolitan area,São Paulo State,Brazil 下载免费PDF全文
André Pitondo‐Silva Gerson Nakazato Juliana P. Falcão Kinue Irino Roberto Martinez Ana Lúcia C. Darini Rodrigo Tavanelli Hernandes 《APMIS : acta pathologica, microbiologica, et immunologica Scandinavica》2015,123(2):128-135
This study was designed to characterize a collection of 60 enteropathogenic Escherichia coli (EPEC) isolates from diarrheic feces of patients in the Ribeirão Preto metropolitan area regarding different phenotypic and molecular features. We examined antibiotic resistance profiles, occurrence of virulence factors‐encoding genes, intimin subtypes and the correlation of serotypes among typical (tEPEC) and atypical (aEPEC) EPEC isolates. The results demonstrated that atypical EPEC was more heterogeneous than typical EPEC concerning the characteristics investigated and 45.2% do not belong to classical EPEC serogroups. Intimin subtype β was the most frequent among the EPEC isolates (46.7%), being detected in both tEPEC and aEPEC. The majority of aEPEC isolates presented localized adherence‐like (LAL) pattern to HEp‐2 cells, although aEPEC isolates displaying diffuse adherence (DA) or non‐adherent were also detected. High prevalence of antimicrobial resistance was found for ampicillin, cephalothin, sulfonamide and tetracycline. In general, tEPEC isolates were more resistant to the antimicrobials tested than aEPEC isolates. 相似文献
15.
16.
J. Alarcón-Rodríguez M. Fernández-Velilla A. Ureña-Vacas J.J. Martín-Pinacho J.A. Rigual-Bobillo A. Jaureguízar-Oriol L. Gorospe-Sarasúa 《Radiologia》2021,63(3):258-269
Most of the patients who overcome the SARS-CoV-2 infection do not present complications and do not require a specific follow-up, but a significant proportion (especially those with moderate / severe clinical forms of the disease) require clinicalradiological follow-up. Although there are hardly any references or clinical guidelines regarding the long-term follow-up of post-COVID-19 patients, radiological exams are being performed and monographic surveillance consultations are being set up in most of the hospitals to meet their needs. The purpose of this work is to share our experience in the management of the post-COVID-19 patient in two institutions thathave had a high incidence of COVID-19 and to propose general follow-uprecommendations from a clinical and radiological perspective. 相似文献
17.
Aoife De Brún Liran Shan Áine Regan Áine McConnon Patrick Wall 《Health communication》2016,31(10):1235-1241
The 2008 dioxin crisis occurred as a result of contamination of Irish pork. The event had significant implications for Ireland’s economy and the reputation of its agricultural industry, as well as raising concerns for human health. This study describes the results of a content analysis of Irish and UK newspaper coverage of the 2008 Irish dioxin crisis, as this is likely to provide insight into how public perceptions of this issue were shaped. Articles from 16 print publications were systematically sampled for the period December 2008 to February 2009. The resulting data set of 141 articles was examined using a coding protocol developed based on previous research and refined during piloting. Results indicated that the dioxin crisis was primarily portrayed by the media as an industry/economic crisis, dominant in 26.9% of articles in the sample. Within this dominant portrayal, the agricultural industry was frequently cited as being in crisis (42.6%); however, the implications of the crisis on the wider economic environment also received attention (17.7%). Differences between Irish and UK-based media were also examined, revealing that while the Irish media most frequently described the crisis in terms of its impact on the industry and economy, the UK media were more likely to portray the crisis as a risk to health. These dominant media messages and message framings have implications for the public understanding of the issue in each country and potential consequences regarding perception of the adequacy of existing food policy and regulatory oversight. 相似文献
18.
19.
A. Prado Rodríguez R. Mato Búa L. Mera Mujico J. Arca Suárez M. López Sánchez L. Sampayo Rodríguez P. Rama-Maceiras 《Revista espa?ola de anestesiología y reanimación》2021,68(6):361-366
Serum lactate is a non-specific marker of tissue hypoperfusion. Elevated serum lactate is used in the differential diagnosis of acute intestinal ischemia. Although this practice is controversial, in the absence of other validated markers lactate is still used because of its high sensitivity.We present the cases of two patients who developed acute mesenteric ischemia as a post-surgical complication. The patients reported moderate abdominal pain —a non-specific symptom in the postoperative context— and tests showed progressively increasing serum lactate levels, which facilitated suspicion and subsequent diagnostic confirmation through an imaging test.These cases highlight the physiopathological importance of lactate elevation in the perioperative context and of performing a differential diagnosis of its possible causes, including mesenteric ischemia. Although the outcome was negative in the first case, early suspicion allowed us to make an effective diagnosis and administer appropriate treatment in the second patient. 相似文献
20.
Alvaro Sepúlveda-Martínez Laura García-Otero Iris Soveral Laura Guirado Brenda Valenzuela-Alcaraz Ximena Torres 《The journal of maternal-fetal & neonatal medicine》2019,32(14):2319-2327
Objective: M-mode and 2D have been proposed for evaluating fetal myocardial thickness. However, studies comparing the performance of both modalities are lacking. We aimed to compare 2D versus M-mode reproducibility for assessing myocardial wall thicknesses.Methods: A prospective study including 45 healthy fetuses from low-risk pregnancies evaluated between 18 and 41 weeks of gestation. Left and right ventricular free-wall and septal myocardial thicknesses were measured at end-diastole (ED) and end-systole (ES) in transverse 4-chamber view using 2D and M-mode. Intra- and interobserver reproducibility was evaluated by the concordance correlation coefficient (CCC). Both techniques were compared by t-test of the CCC.Results: 2D and M-mode demonstrated excellent and similar intraobserver repeatability, with the best concordance in ES septal thickness (M-mode CCC 0.956 versus 2D-mode CCC 0.914). Interobserver reproducibility demonstrated also a high concordance, optimal in ES left ventricular free wall (M-mode 0.925 versus 2 D 0.855). Comparison of both techniques demonstrated a high concordance in all measurements, except for ED septal thickness with better reproducibility using M-mode (CCC 0.954 versus 0.847, p?=?.017).Conclusions: 2D and M-mode can be used in a reproducible manner for measuring fetal myocardial thickness, with a slightly better performance of M-mode for assessing ED septal wall thickness. 相似文献