全文获取类型
收费全文 | 3584篇 |
免费 | 193篇 |
国内免费 | 18篇 |
专业分类
耳鼻咽喉 | 30篇 |
儿科学 | 62篇 |
妇产科学 | 67篇 |
基础医学 | 499篇 |
口腔科学 | 121篇 |
临床医学 | 221篇 |
内科学 | 941篇 |
皮肤病学 | 109篇 |
神经病学 | 319篇 |
特种医学 | 199篇 |
外科学 | 480篇 |
综合类 | 25篇 |
预防医学 | 315篇 |
眼科学 | 83篇 |
药学 | 147篇 |
中国医学 | 11篇 |
肿瘤学 | 166篇 |
出版年
2024年 | 2篇 |
2023年 | 31篇 |
2022年 | 69篇 |
2021年 | 134篇 |
2020年 | 74篇 |
2019年 | 103篇 |
2018年 | 117篇 |
2017年 | 80篇 |
2016年 | 94篇 |
2015年 | 124篇 |
2014年 | 166篇 |
2013年 | 180篇 |
2012年 | 284篇 |
2011年 | 274篇 |
2010年 | 166篇 |
2009年 | 134篇 |
2008年 | 242篇 |
2007年 | 267篇 |
2006年 | 265篇 |
2005年 | 206篇 |
2004年 | 214篇 |
2003年 | 186篇 |
2002年 | 157篇 |
2001年 | 32篇 |
2000年 | 27篇 |
1999年 | 20篇 |
1998年 | 33篇 |
1997年 | 14篇 |
1996年 | 16篇 |
1995年 | 10篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1982年 | 8篇 |
1981年 | 5篇 |
1980年 | 2篇 |
1976年 | 3篇 |
1969年 | 1篇 |
1963年 | 2篇 |
1962年 | 1篇 |
1956年 | 1篇 |
1945年 | 1篇 |
排序方式: 共有3795条查询结果,搜索用时 15 毫秒
61.
Mauricio Hincapié Miguel de Jesús Ramírez Antonio Valenzuela José Alberto Valdez 《International Journal on Interactive Design and Manufacturing》2014,8(3):209-230
The automation of manufacturing systems is one of the most important aspects that need to be taken care of during a design process. The Product Lifecycle Management (PLM) tools allow for the designing of automated systems even before acquiring all the hardware and/or software. This paper shows the use of this PLM kind of tools for mixing virtual and real components on an automated manufacturing system through the implementation of four different case scenarios: using the real process/real controller to the virtual process/virtual controller, real process/real controller to real process/virtual controller and finally, virtual process/real controller to virtual process/virtual controller. These scenarios will be described along with their purposes and the tools used to achieve them. Dassault Systemes DELMIA Automation is used as a PLM tool and is combined with the hardware and software required to achieve each case scenario. The case study used is the Flexible Manufacturing System in the Mechatronics laboratory at the Tecnológico de Monterrey; it’s also presented an implementation of these scenarios in a Manufacturing Systems Automation laboratory class. This study examines students’ use of technology for learning compared to more traditional learning methods. Results suggest that there is more than one good way to learn. 相似文献
62.
Natlia Maria Vieira Barbosa Ana Cludia de Castro Ferreira Conti Leopoldino Capelozza-Filho Renata Rodrigues de Almeida-Pedrin Mauricio de Almeida Cardoso 《The Angle orthodontist》2019,89(1):71
Objectives:To assess reliability and reproducibility of the individual assessment of midpalatal suture maturation in computed tomography among orthodontists and radiologists for potential diagnosis application.Materials and Methods:Sixty axial slices from cone-beam computed tomography and multi-slice CT scans of patients aged between 11 and 21 years old (33 females and 27 males) were selected. For the investigation of reliability and reproducibility of the method, two groups of examiners were established. The first group consisted of 11 orthodontists and the second consisted of 10 radiologists. Each group examined the images and performed individual assessment of the midpalatal suture maturation method twice within an interval of 21 days. During the first and second analyses, the sequence of images was randomized to reduce potential bias. Weighted Cohen''s kappa was performed to assess inter- and intra-examiners'' agreement. The percentage of perfect agreement and the number of stages apart for each disagreement were calculated. The significance level was P < .05.Results:The overall inter-examiner agreement was satisfactory in the first (kappaw: 0.37) and the second (kappaw: 0.34) analyses. Intra-examiner agreement outcomes were similar between orthodontists (kappaw: 0.44) and radiologists (kappaw: 0.41). The percentage of perfect agreement was 43.2%.Conclusions:The method for individual assessment of midpalatal suture maturation revealed potential reliability and reproducibility. However, the agreement rate observed in the present study was not high enough for a method designed for routine clinical applications. 相似文献
63.
Madelon Novato Ribeiro Maria Inês Fernandes Pimentel Armando de Oliveira Schubach Raquel de Vasconcellos Carvalh?es de Oliveira José Liporage Teixeira Madson Pedro da Silva Leite Monique Fonseca Ginelza Peres Lima dos Santos Mariza Matos Salgueiro Erica de Camargo Ferreira e Vasconcellos Marcelo Rosandiski Lyra Mauricio Naoto Saheki Claudia Maria Valete-Rosalino 《Revista do Instituto de Medicina Tropical de S?o Paulo》2014,56(4):291-296
The favorable outcome of the treatment of a disease is influenced by the
adherence to therapy. Our objective was to assess factors associated with adherence
to treatment of patients included in a clinical trial of equivalence between the
standard and alternative treatment schemes with meglumine antimoniate (MA) in the
treatment of cutaneous leishmaniasis (CL), in the state of Rio de Janeiro. Between
2008 and 2011, 57 patients with CL were interviewed using a questionnaire to collect
socioeconomic data. The following methods were used for adherence monitoring:
counting of vial surplus, monitoring card, Morisky test and modified Morisky test
(without the question regarding the schedule); we observed 82.1% (vial return), 86.0%
(monitoring card), 66.7% (Morisky test) and 86.0% (modified Morisky test) adherence.
There was a strong correlation between the method of vial counting and the monitoring
card and modified Morisky test. A significant association was observed between
greater adherence to treatment and low dose of MA, as well as with a lower number of
people sleeping in the same room. We recommend the use of the modified Morisky test
to assess adherence to treatment of CL with MA, because it is a simple method and
with a good performance, when compared to other methods. 相似文献
64.
Astrid Meireles Santos Mauricio Ibrahim Scanavacca Francisco Darrieux Bárbara Ianni Sissy Lara de Melo Cristiano Pisani Francisco Santos Neto Eduardo Sosa Denise Tessariol Hachul 《Arquivos brasileiros de cardiologia》2014,102(6):579-587
Background
Sudden death is the leading cause of death in Chagas disease (CD), even in patients with preserved ejection fraction (EF), suggesting that destabilizing factors of the arrhythmogenic substrate (autonomic modulation) contribute to its occurrence.Objective
To determine baroreflex sensitivity (BRS) in patients with undetermined CD (GI), arrhythmogenic CD with nonsustained ventricular tachycardia (NSVT) (GII) and CD with spontaneous sustained ventricular tachycardia (STV) (GIII), to evaluate its association with the occurrence and complexity of arrhythmias.Method
Forty-two patients with CD underwent ECG and continuous and noninvasive BP monitoring (TASK force monitor). The following were determined: BRS (phenylephrine method); heart rate variability (HRV) on 24-h Holter; and EF (echocardiogram).Results
GIII had lower BRS (6.09 ms/mm Hg) as compared to GII (11.84) and GI (15.23). The difference was significant between GI and GIII (p = 0.01). Correlating BRS with the density of ventricular extrasystoles (VE), low VE density (<10/h) was associated with preserved BRS. Only 59% of the patients with high VE density (> 10/h) had preserved BRS (p = 0.003). Patients with depressed BRS had higher VE density (p = 0.01), regardless of the EF. The BRS was the only variable related to the occurrence of SVT (p = 0.028).Conclusion
The BRS is preserved in undetermined CD. The BRS impairment increases as disease progresses, being more severe in patients with more complex ventricular arrhythmias. The degree of autonomic dysfunction did not correlate with EF, but with the density and complexity of ventricular arrhythmias. 相似文献65.
M Castellanos R Pérez C Carrasco M Hernando-Pérez J Gómez-Herrero PJ de Pablo MG Mateu 《Proceedings of the National Academy of Sciences of the United States of America》2012,109(30):12028-12033
In this study we test the hypothesis that mechanically elastic regions in a virus particle (or large biomolecular complex) must coincide with conformationally dynamic regions, because both properties are intrinsically correlated. Hypothesis-derived predictions were subjected to verification by using 19 variants of the minute virus of mice capsid. The structural modifications in these variants reduced, preserved, or restored the conformational dynamism of regions surrounding capsid pores that are involved in molecular translocation events required for virus infectivity. The mechanical elasticity of the modified capsids was analyzed by atomic force microscopy, and the results corroborated every prediction tested: Any mutation (or chemical cross-linking) that impaired a conformational rearrangement of the pore regions increased their mechanical stiffness. On the contrary, any mutation that preserved the dynamics of the pore regions also preserved their elasticity. Moreover, any pseudo-reversion that restored the dynamics of the pore regions (lost through previous mutation) also restored their elasticity. Finally, no correlation was observed between dynamics of the pore regions and mechanical elasticity of other capsid regions. This study (i) corroborates the hypothesis that local mechanical elasticity and conformational dynamics in a viral particle are intrinsically correlated; (ii) proposes that determination by atomic force microscopy of local mechanical elasticity, combined with mutational analysis, may be used to identify and study conformationally dynamic regions in virus particles and large biomolecular complexes; (iii) supports a connection between mechanical properties and biological function in a virus; (iv) shows that viral capsids can be greatly stiffened by protein engineering for nanotechnological applications. 相似文献
66.
Kuga MC dos Santos Nunes Reis JM Fabrício S Bonetti-Filho I de Campos EA Faria G 《Dental traumatology》2012,28(3):238-242
Abstract – Objectives: To compare the fracture resistance of bovine teeth after intracoronal bleaching with sodium percarbonate (SPC) or sodium perborate (SP) mixed with water or 20% hydrogen peroxide (HP). Materials and methods: Fifty extracted bovine teeth were divided into four experimental groups (G1–G4) and one control (n = 10) after endodontic treatment. Following root canal obturation, a glass ionomer barrier was placed at the cemento–enamel junction. After that, the pulp chambers were filled with: G1 – SP with water; G2 – SP with 20% HP; G3 – SPC with water; and G4 – SPC with 20% HP. No bleaching agent was used in the control group. Coronal access cavities were sealed with glass ionomer and specimens were immersed in artificial saliva. The bleaching agents were replaced after 7 days, and teeth were kept in artificial saliva for an additional 7 days, after which the pastes were removed and the coronal access cavities were restored with glass ionomer. Crowns were subjected to compressive load at a cross head speed of 0.5 mm min?1 applied at 135° to the long axis of the root by an EMIC DL2000 testing machine, until coronal fracture. Data were statistically analysed by anova and Tukey test. Results: No differences in fracture resistance were observed between the experimental groups (P > 0.05). However, all experimental groups presented lower fracture resistance than the control group (P < 0.05). Conclusion: SPC and SP led to equal reduction on fracture resistance of dental crowns, regardless of being mixed with water or 20% HP. 相似文献
67.
Evan W. Carson Rochelle R. Beasley Kenneth L. Jones Stacey L. Lance Ma de Lourdes Lozano-Vilano Lilia Vela-Valladares Iris Banda-Villanueva Thomas F. Turner Mauricio De la Maza-Benignos 《Conservation Genetics Resources》2013,5(3):853-856
We developed microsatellite loci for the Julimes pupfish, Cyprinodon julimes. Twenty-five loci were screened across 19 individuals from Julimes Spring, Chihuahua, Mexico. The number of alleles per locus ranged from 2 to 14, observed heterozygosity ranged from 0.105 to 0.947, and the probability of identity values ranged from 0.022 to 0.588. We then tested for cross-amplification in the bighead pupfish, C. pachycephalus; twenty-three individuals from San Diego de Alcalá, Chihuahua, Mexico, were screened across the 20 loci that amplified cleanly. These new loci will be used for long-term genetic monitoring of these critically endangered species. 相似文献
68.
69.
70.