全文获取类型
收费全文 | 27036篇 |
免费 | 1429篇 |
国内免费 | 142篇 |
专业分类
耳鼻咽喉 | 311篇 |
儿科学 | 517篇 |
妇产科学 | 572篇 |
基础医学 | 3324篇 |
口腔科学 | 1266篇 |
临床医学 | 1940篇 |
内科学 | 7267篇 |
皮肤病学 | 769篇 |
神经病学 | 2080篇 |
特种医学 | 522篇 |
外科学 | 4167篇 |
综合类 | 133篇 |
一般理论 | 4篇 |
预防医学 | 2168篇 |
眼科学 | 543篇 |
药学 | 1501篇 |
中国医学 | 115篇 |
肿瘤学 | 1408篇 |
出版年
2024年 | 15篇 |
2023年 | 165篇 |
2022年 | 331篇 |
2021年 | 974篇 |
2020年 | 517篇 |
2019年 | 831篇 |
2018年 | 1060篇 |
2017年 | 613篇 |
2016年 | 607篇 |
2015年 | 787篇 |
2014年 | 1158篇 |
2013年 | 1355篇 |
2012年 | 2160篇 |
2011年 | 2278篇 |
2010年 | 1227篇 |
2009年 | 1165篇 |
2008年 | 1777篇 |
2007年 | 1903篇 |
2006年 | 1768篇 |
2005年 | 1666篇 |
2004年 | 1441篇 |
2003年 | 1252篇 |
2002年 | 1219篇 |
2001年 | 184篇 |
2000年 | 199篇 |
1999年 | 211篇 |
1998年 | 203篇 |
1997年 | 187篇 |
1996年 | 147篇 |
1995年 | 112篇 |
1994年 | 93篇 |
1993年 | 95篇 |
1992年 | 88篇 |
1991年 | 96篇 |
1990年 | 71篇 |
1989年 | 55篇 |
1988年 | 37篇 |
1987年 | 39篇 |
1986年 | 45篇 |
1985年 | 42篇 |
1984年 | 42篇 |
1983年 | 34篇 |
1982年 | 41篇 |
1981年 | 60篇 |
1980年 | 27篇 |
1979年 | 30篇 |
1978年 | 18篇 |
1976年 | 21篇 |
1974年 | 18篇 |
1971年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 203 毫秒
991.
992.
Miquel À. Mas Sebastià J. Santaeugènia Francisco J. Tarazona-Santabalbina Sara Gámez Marco Inzitari 《Journal of the American Medical Directors Association》2018,19(10):860-863
Objectives
To compare clinical outcomes in older patients with acute medical crises attended by a geriatrician-led home hospitalization unit (HHU) vs an inpatient intermediate-care geriatric unit (ICGU) in a post-acute care setting.Design
Quasi-experimental longitudinal study, with 30-day follow-up.Participants
Older patients with chronic conditions attended at the emergency department or day hospital for an acute medical crisis.Interventions
Patients were referred to geriatrician-led HHU or ICGU wards.Setting
An acute care hospital, an intermediate care hospital, and the community of an urban area in the North of Barcelona, in Southern Europe.Measurements
We compared health crisis outcomes (recovery from the acute health crisis, referral to an acute hospital, or death), length of stay, relative functional gain (RFG) at discharge, readmission to an acute care unit within 30 days of discharge, and mortality within 30 days of discharge.Results
We included 171 older adults (57 in the HHU and 114 in the ICGU) with complex conditions at risk of negative outcomes. At baseline, HHU patients were significantly younger and less likely to be cognitively impaired and referred from an emergency department. Most patients in both groups recovered from their health crises (91.2% in the HHU group vs 88.6% in the ICGU group, P = .79). No differences were found between the 2 groups in 30-day mortality (8.6% vs 9.6%, P = >.99). There was a trend toward lower 30-day readmission to an acute care unit in the HHU group (10.5% vs 19.3% in the ICGU group, P = .19). HHU patients had higher RFG (mean 0.75 days vs 0.51 in the ICGU group, P = .01), and a longer stay in the unit (9.7 vs 8.2 days in the ICGU group, P < .01).Conclusions
These preliminary results suggest that the geriatrician-led HHU seems effective in resolving acute medical crises in older patients with chronic disease. Patients attended by the HHU obtained better functional outcomes compared to those from the ICGU, although the groups did have some baseline differences. 相似文献993.
Dario Carradori Claudia Balducci Francesca Re Davide Brambilla Benjamin Le Droumaguet Orfeu Flores Alice Gaudin Simona Mura Gianluigi Forloni Lara Ordoñez-Gutierrez Francisco Wandosell Massimo Masserini Patrick Couvreur Julien Nicolas Karine Andrieux 《Nanomedicine : nanotechnology, biology, and medicine》2018,14(2):609-618
Alzheimer's disease (AD) is a neurodegenerative disorder related, in part, to the accumulation of amyloid-β peptide (Aβ) and especially the Aβ peptide 1-42 (Aβ1-42). The aim of this study was to design nanocarriers able to: (i) interact with the Aβ1-42 in the blood and promote its elimination through the “sink effect” and (ii) correct the memory defect observed in AD-like transgenic mice. To do so, biodegradable, PEGylated nanoparticles were surface-functionalized with an antibody directed against Aβ1-42. Treatment of AD-like transgenic mice with anti-Aβ1-42-functionalized nanoparticles led to: (i) complete correction of the memory defect; (ii) significant reduction of the Aβ soluble peptide and its oligomer level in the brain and (iii) significant increase of the Aβ levels in plasma. This study represents the first example of Aβ1-42 monoclonal antibody-decorated nanoparticle-based therapy against AD leading to complete correction of the memory defect in an experimental model of AD. 相似文献
994.
Unravelling residents’ and supervisors’ workplace interactions: an intersubjectivity study 下载免费PDF全文
Francisco M Olmos‐Vega Diana HJM Dolmans Carlos Guzmán‐Quintero Renée E Stalmeijer Pim W Teunissen 《Medical education》2018,52(7):725-735
Context
Successful engagement between residents and supervisors lies at the core of workplace learning, a process that is not exempt from challenge. Clinical encounters have unique learning potential as they offer opportunities to achieve a shared understanding between the resident and supervisor of how to accomplish a common goal. How residents and supervisors develop such a mutual understanding is an issue that has received limited attention in the literature. We used the ‘intersubjectivity’ concept as a novel conceptual framework to analyse this issue.Methods
We conducted a constructivist grounded theory study in an anaesthesiology department in Bogota, Colombia, using focus groups and field observations. Eleven residents of different training levels and 18 supervisors with varying years of teaching experience participated in the study. Through iterative data analysis, collection and constant comparison, we constructed the final results.Results
We found that residents and supervisors achieved a shared understanding by adapting to one another in the process of providing patient care. Continuous changes in the composition of resident–supervisor dyads exposed them to many procedural variations, to which they responded by engaging in various adaptation patterns that included compliance by residents with supervisors’ directions, negotiation by residents of supervisors’ preferences, and the sharing of decision making. In the process, the resident played an increasingly key role as a member of the supervisory dyad. Additionally, experiencing these adaptation patterns repeatedly resulted in the creation of a working repertoire: an attuned working code used by the members of each supervisory dyad to work together as a team.Conclusions
The development of shared understanding between residents and supervisors entailed experiencing diverse adaptation patterns which resulted in the creation of working repertoires. Seeing supervisory interactions as adaptation processes has essential theoretical and practical implications regarding workplace learning in postgraduate settings. Our findings call for further exploration to understand learning in postgraduate education as a social process.995.
996.
997.
Maria de Paula Caldas Gláucia Maria Bovi Ambrosano Francisco Haiter Neto 《Journal of applied oral science : revista FOB》2007,15(2):144-147
Objective:
The purpose of this study was to investigate whether skeletal maturation using cephalometric radiographs could be used in a Brazilian population.Material and Methods:
The study population was selected from the files of the Oral Radiological Clinic of the Dental School of Piracicaba, Brazil and consisted of 128 girls and 110 boys (7.0 to 15.9 years old) who had cephalometric and hand-wrist radiographs taken on the same day. Cervical vertebral bone age was evaluated using the method described by Mito and colleagues in 2002. Bone age was assessed by the Tanner-Whitehouse (TW3) method and was used as a gold standard to determine the reliability of cervical vertebral bone age. An analysis of variance and Tukey''s post-hoc test were used to compare cervical vertebral bone age, bone age and chronological age at 5% significance level.Results:
The analysis of the Brazilian female children data showed that there was a statistically significant difference (p<0.05) between cervical vertebral bone age and chronological age and between bone age and chronological age. However no statistically significant difference (p>0.05) was found between cervical vertebral bone age and bone age. Differently, the analysis of the male children data revealed a statistically significant difference (p<0.05) between cervical vertebral bone age and bone age and between cervical vertebral bone age and chronological age (p<0.05).Conclusions:
The findings of the present study suggest that the method for objectively evaluating skeletal maturation on cephalometric radiographs by determination of vertebral bone age can be applied to Brazilian females only. The development of a new method to objectively evaluate cervical vertebral bone age in males is needed. 相似文献998.
Lucio Mitsuo Kurita Alynne Vieira Menezes Marcia Spinelli Casanova Francisco Haiter-Neto 《Journal of applied oral science : revista FOB》2007,15(2):99-104
Objective:
The purpose of this investigation was to evaluate the applicability of the methods proposed by Nolla and by Nicodemo and colleagues for assessing dental age and its correlation to chronological age.Methods:
Panoramic radiographs of 360 patients from the city of Fortaleza (CE, Brazil) aged 7-15 years were used to assess the associations between dental and chronological age. Data were submitted to statistical analysis using the BioEstat 2.0 (2000) software. Student-Neuman-Keuls test was performed and Pearson''s correlation coefficients were calculated at 5% significance level.Results:
When the Nolla method was applied, the mean difference between true and estimated age for males and females was underestimated. The use of the method proposed by Nicodemo and colleagues also resulted in underestimation, although it was more evident in male subjects. The correlation coefficients between chronological age and estimated dental age were high, with mean values ranging between 0.87 and 0.91 for males and between 0.84 and 0.93 for females.Conclusion:
Although both methods proved to be reliable in estimating age, the use of correction factors is recommended. 相似文献999.
Maniglia-Ferreira C Gurgel-Filho ED Silva JB Paula RC Feitosa JP Gomes BP Souza-Filho FJ 《Brazilian Oral Research》2007,21(1):29-34
This study was undertaken to explore the effect of heating on gutta-percha, analyzing the occurrence of endothermic peaks corresponding to the transformation that occurs in the crystalline structure of the polymer during thermal manipulation. This study also sought to determine the temperature at which these peaks occur, causing a transformation from the beta- to the alpha-form, and from the alpha- to the amorphous phase. Eight nonstandardized gutta-percha points commercially available in Brazil (Konne, Tanari, Endopoint, Odous, Dentsply 0.04, Dentsply 0.06, Dentsply TP, Dentsply FM) and pure gutta-percha (control) were analysed using differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). The transition temperatures were determined and analysed. With the exception of Dentsply 0.04 and Dentsply 0.06, the majority of the products showed thermal behaviour typical of beta-gutta-percha, with two endothermic peaks, exhibiting two crystalline transformations upon heating from ambient temperature to 130 degrees. Upon cooling and reheating, few samples presented two endothermic peaks. It was concluded that heating dental gutta-percha to 130 degrees C causes changes to its chemical structure which permanently alter its physical properties. 相似文献
1000.
The rat model is widely used in periodontal research and the quality of histological sections is essential. The purpose of this study was to evaluate the histological characteristics of periodontal tissues in Wistar rat maxillae, with different times of fixation and decalcified by nitric acid or formic acid (Anna Morse Solution). Fifteen rats were used. Fixation was performed for 24, 48 and 72 hours. The maxillae were hemi-sectioned and each part was decalcified either in nitric acid for 7 days or in Anna Morse solution for 35 days. Two trained and blinded examiners performed the evaluation. Fourty eight hours of fixation and decalcification with Anna Morse solution showed more clear characteristics of the epithelium-connective tissue interface and of the periodontal structures. Mean measurements between the cementum-enamel junction and the bone crest varied in the different experimental times from 176.5 (+/- 60.45) to 210.94 (+/- 39.33) pixels on the buccal aspect, and from 199.69 (+/- 38.33) to 298.55 (+/-70.81) pixels on the palatal aspect, with no statistically significant differences (ANOVA, p > 0.05). In the same fixation period, decalcification with nitric acid or Anna Morse solution did not display any statistically significant differences. It may be concluded that for a qualitative histological analysis, fixation should preferably be for 48 hours and the demineralization should be made by Anna Morse solution. For a histomorphometric analysis, the decalcification solution does not interfere in the results. 相似文献