全文获取类型
收费全文 | 21551篇 |
免费 | 1358篇 |
国内免费 | 76篇 |
专业分类
耳鼻咽喉 | 352篇 |
儿科学 | 635篇 |
妇产科学 | 765篇 |
基础医学 | 3046篇 |
口腔科学 | 1226篇 |
临床医学 | 1524篇 |
内科学 | 4641篇 |
皮肤病学 | 744篇 |
神经病学 | 2007篇 |
特种医学 | 572篇 |
外国民族医学 | 1篇 |
外科学 | 3304篇 |
综合类 | 107篇 |
一般理论 | 8篇 |
预防医学 | 1497篇 |
眼科学 | 346篇 |
药学 | 1095篇 |
中国医学 | 88篇 |
肿瘤学 | 1027篇 |
出版年
2024年 | 57篇 |
2023年 | 170篇 |
2022年 | 386篇 |
2021年 | 690篇 |
2020年 | 463篇 |
2019年 | 602篇 |
2018年 | 726篇 |
2017年 | 502篇 |
2016年 | 526篇 |
2015年 | 662篇 |
2014年 | 881篇 |
2013年 | 1018篇 |
2012年 | 1536篇 |
2011年 | 1632篇 |
2010年 | 987篇 |
2009年 | 854篇 |
2008年 | 1375篇 |
2007年 | 1368篇 |
2006年 | 1290篇 |
2005年 | 1232篇 |
2004年 | 979篇 |
2003年 | 877篇 |
2002年 | 788篇 |
2001年 | 288篇 |
2000年 | 284篇 |
1999年 | 286篇 |
1998年 | 162篇 |
1997年 | 178篇 |
1996年 | 139篇 |
1995年 | 131篇 |
1994年 | 100篇 |
1993年 | 93篇 |
1992年 | 157篇 |
1991年 | 154篇 |
1990年 | 138篇 |
1989年 | 121篇 |
1988年 | 151篇 |
1987年 | 109篇 |
1986年 | 114篇 |
1985年 | 77篇 |
1984年 | 78篇 |
1983年 | 58篇 |
1982年 | 49篇 |
1981年 | 49篇 |
1980年 | 39篇 |
1979年 | 47篇 |
1978年 | 33篇 |
1977年 | 37篇 |
1976年 | 43篇 |
1974年 | 50篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Ricardo Fernández-Fernández Jesus M. Martínez-Miranda Enrique Gil-Garay 《The Journal of arthroplasty》2018,33(4):1139-1143
Background
Cobalt-chromium (Co-Cr) and titanium (Ti) have been the most popular materials employed for cementless implants. The purpose of this study was to compare clinical and radiological results of a single stem design with both alloys at long-term follow-up.Methods
Two hundred consecutive uncemented stems implanted in 171 patients (100 Co-Cr and 100 Ti implants) between 1999 and 2002 were studied. Mean age of the patients was 60.9 years (range, 20-84). Clinical results were evaluated using the Harris hip score. The presence of thigh pain was also analyzed. Stem fixation was graded according to Engh criteria. Radiolucent lines, osteolysis, and stem subsidence were also analyzed.Results
At 15-year follow-up, no stems had been revised. Both groups showed similar clinical results with mean Harris hip score of 93.4 (Co-Cr) vs 93.9 (Ti). There was no difference in the rate of thigh pain (11 vs 8.3, respectively, P = .507). Radiolucent lines were more frequent in the Co-Cr group (63.6% vs 35.6%, P < .001).Conclusion
Ti stems showed better osteointegration than Co-Cr stems, with a significantly lower incidence of radiolucent lines. However, this did not affect the clinical results or the appearance of thigh pain. 相似文献82.
83.
Objectives The integral involvement of sinus and skull base surgeries in the field of otolaryngology makes the endonasal vasculature including the ethmoidal arteries important to consider. The anterior ethmoidal artery (AEA) and posterior ethmoidal artery (PEA) are well-known entities, yet the relatively recent notion of accessory or middle ethmoidal vessels complicates our understanding of this arterial system.
Study Design Radiographic study.
Methods Fifty computed tomographic angiographies were studied for the presence of accessory/middle ethmoidal arteries (MEAs). If contrasted arteries were not visualized reliably, foramina were accepted as evidence of arteries. The accessory arteries/foramina were then compared with the locations of the AEA and PEA.
Results A total of 19 of the 50 patient samples studied had evidence of a right, left, or bilateral middle ethmoidal vessels (38%). Overall, 26 arteries total were identified out of the 100 sides (26%). Unilateral middle arteries were more common than bilateral, and right sided were more common than left. There was no evidence of multiple MEAs on a given side.
Conclusion The endonasal surgeon must be cognizant of the possible presence of MEAs. These arteries should be considered when working in the medial orbit and anterior skull base region. 相似文献
84.
Preclinical cadaveric study of transanal robotic proctectomy with total mesorectal excision combined with laparoscopic assistance 下载免费PDF全文
85.
Stephen M. Smith Alessandra C. Schmitt Ricardo L. Carrau O. Hans Iwenofu 《Head and neck pathology》2015,9(1):165-171
The broad morphologic spectrum, inherent immunophenotypic heterogeneity of malignant melanoma and its rarity in the sinonasal tract are major challenges in eliciting the correct diagnosis, which may lead to misclassification and inadequate medical management. Herein, we describe a single case of a 70 year-old male with sinonasal mucosal melanoma, exhibiting varying histologic phenotypes including small round blue cell morphology, epithelioid and focal rhabdoid morphology and strong, diffuse desmin immunoreactivity. These constellation of features initially prompted the diagnosis of rhabdomyosarcoma. The differential diagnosis in this anatomic area includes other malignant small round blue cell tumors of the sinonasal mucosa such as rhabdomyosarcoma, olfactory neuroblastoma, sinonasal undifferentiated carcinoma, and lymphoma. We reviewed precedent literature and further discuss the potential pitfalls to which pathologists may be prone. 相似文献
86.
Lucio Díaz-Flores Ricardo Gutiérrez M.ª Pino García M. González-Gómez Francisco J. Sáez Lucio Díaz-Flores José Luis Carrasco Juan F. Madrid 《Acta histochemica》2018,120(3):255-262
Sinusoidal hemangioma, characterized by interconnecting thin-walled vascular spaces, may present papillae/pseudo-papillae and zones that resemble intravascular papillary endothelial hyperplasia (IPEH). Our objectives are to explore the existence of zones in IPEH with sinusoidal hemangioma characteristics, the mechanism of papillary and septa formation in sinusoidal hemangioma and the comparison of this mechanism with that in IPEH. For these purposes, specimens of 4 cases of each entity were selected and studied by serial histologic sections and by immunochemistry and immunofluorescence procedures. The results showed a) zones with characteristics of sinusoidal hemangioma in IPEH cases, b) presence in both entities of papillae with a cover formed by a monolayer of CD34+ and CD31+ endothelial cells (ECs) and a core formed by either type I collagen and αSMA+ cells (presenting a pericyte/smooth muscle cell aspect) or thrombotic components, and c) a similar piecemeal angiogenic mechanism in papillary formation, including sprouting of intimal ECs toward the vessel wall itself or intravascular thrombi, formation of vascular loops that encircle and separate vessel wall or thrombus components, and parietal or thrombotic papillae development. The major differences between both entities were the number, arrangement and substrate of papillae: myriad, densely grouped, parietal and thrombotic papillae in IPEH, and a linear arrangement of predominant parietal papillae in sinusoidal hemangioma, originating septa (segmentation). In conclusion, sinusoidal hemangioma and IPEH are interrelated processes, which share morphologic findings and a piecemeal angiogenic mechanism, combining sprouting and intussusceptive angiogenesis, and leading to papillary formation and vessel segmentation. 相似文献
87.
G. J. Sturm E.‐M. Varga G. Roberts H. Mosbech M. B. Bilò C. A. Akdis D. Antolín‐Amérigo E. Cichocka‐Jarosz R. Gawlik T. Jakob M. Kosnik J. Lange E. Mingomataj D. I. Mitsias M. Ollert J. N. G. Oude Elberink O. Pfaar C. Pitsios V. Pravettoni F. Ruëff B. A. Sin I. Agache E. Angier S. Arasi M. A. Calderón M. Fernandez‐Rivas S. Halken M. Jutel S. Lau G. B. Pajno R. van Ree D. Ryan O. Spranger R. G. van Wijk S. Dhami H. Zaman A. Sheikh A. Muraro 《Allergy》2018,73(4):744-764
Hymenoptera venom allergy is a potentially life‐threatening allergic reaction following a honeybee, vespid, or ant sting. Systemic‐allergic sting reactions have been reported in up to 7.5% of adults and up to 3.4% of children. They can be mild and restricted to the skin or moderate to severe with a risk of life‐threatening anaphylaxis. Patients should carry an emergency kit containing an adrenaline autoinjector, H1‐antihistamines, and corticosteroids depending on the severity of their previous sting reaction(s). The only treatment to prevent further systemic sting reactions is venom immunotherapy. This guideline has been prepared by the European Academy of Allergy and Clinical Immunology's (EAACI) Taskforce on Venom Immunotherapy as part of the EAACI Guidelines on Allergen Immunotherapy initiative. The guideline aims to provide evidence‐based recommendations for the use of venom immunotherapy, has been informed by a formal systematic review and meta‐analysis and produced using the Appraisal of Guidelines for Research and Evaluation (AGREE II) approach. The process included representation from a range of stakeholders. Venom immunotherapy is indicated in venom‐allergic children and adults to prevent further moderate‐to‐severe systemic sting reactions. Venom immunotherapy is also recommended in adults with only generalized skin reactions as it results in significant improvements in quality of life compared to carrying an adrenaline autoinjector. This guideline aims to give practical advice on performing venom immunotherapy. Key sections cover general considerations before initiating venom immunotherapy, evidence‐based clinical recommendations, risk factors for adverse events and for relapse of systemic sting reaction, and a summary of gaps in the evidence. 相似文献
88.
Matheus C. Martini Leonardo C. Caserta Marcia M. A. B. dos Santos Ana C. S. Barnabé Ricardo Durães-Carvalho Marina A. Padilla 《Avian pathology》2018,47(3):286-293
The detection of avian coronaviruses (AvCoV) in wild birds and the emergence of new AvCoV have increased in the past few years. In the present study, the pathogenicity of three AvCoV isolates was investigated in day-old chicks. One AvCoV isolated from a pigeon, which clustered with the Massachusetts vaccine serotype, and two AvCoV isolated from chickens, which grouped with a Brazilian genotype lineage, were used. Clinical signs, gross lesions, histopathological changes, ciliary activity, viral RNA detection, and serology were evaluated during 42 days post infection. All AvCoV isolates induced clinical signs, gross lesions in the trachea, moderate histopathological changes in the respiratory tract, and mild changes in other tissues. AvCoV isolated from the pigeon sample caused complete tracheal ciliostasis over a longer time span. Specific viral RNA was detected in all tissues, but the highest RNA loads were detected in the digestive tract (cloacal swabs and ileum). The highest antibody levels were also detected in the group infected with an isolate from the pigeon. These results confirm the pathogenicity of Brazilian variants, which can cause disease and induce gross lesions and histopathological changes in chickens. Our results suggest that non-Galliformes birds can also play a role in the ecology of AvCoV. 相似文献
89.
Yvonne R. Thorstenson Lisa E. Creary Huang Huang Virginie Rozot Tracy T. Nguyen Farbod Babrzadeh Sandeep Kancharla Marilyn Fukushima Raquel Kuehn Chunlin Wang Ming Li Sujatha Krishnakumar Michael Mindrinos Marcelo A. Fernandez Viña Thomas J. Scriba Mark M. Davis 《Human immunology》2018,79(12):839-847
The development of next-generation sequencing (NGS) methods for HLA genotyping has already had an impact on the scope and precision of HLA research. In this study, allelic resolution HLA typing was obtained for 402 individuals from Cape Town, South Africa. The data were produced by high-throughput NGS sequencing as part of a study of T-cell responses to Mycobacterium tuberculosis in collaboration with the University of Cape Town and Stanford University. All samples were genotyped for 11 HLA loci, namely HLA-A, -B, -C, -DPA1, -DPB1, -DQA1, -DQB1, -DRB1, -DRB3, -DRB4, and -DRB5. NGS HLA typing of samples from Cape Town inhabitants revealed a unique cohort, including unusual haplotypes, and 22 novel alleles not previously reported in the IPD-IMGT/HLA Database. Eight novel alleles were in Class I loci and 14 were in Class II. There were 62 different alleles of HLA-A, 72 of HLA-B, and 47 of HLA-C. Alleles A123:17, A143:01, A129:11, A168:27:01, A101:23, B114:01:01, B115:10:01, B139:10:01, B145:07, B182:02:01 and C108:04:01 were notably more frequent in Cape Town compared to other populations reported in the literature. Class II loci had 21 different alleles of DPA1, 46 of DPB1, 27 of DQA1, 26 of DQB1, 41 of DRB1, 5 of DRB3, 4 of DRB4 and 6 of DRB5. The Cape Town cohort exhibited high degrees of HLA diversity and relatively high heterozygosity at most loci. Genetic distances between Cape Town and five other sub-Saharan African populations were also calculated and compared to European Americans. 相似文献
90.
Chacón-Vargas Karla Fabiola Andrade-Ochoa Sergio Nogueda-Torres Benjamín Juárez-Ramírez Dulce Carolina Lara-Ramírez Edgar E. Mondragón-Flores Ricardo Monge Antonio Rivera Gildardo Sánchez-Torres Luvia Enid 《Parasitology research》2018,117(1):45-58
Parasitology Research - Leishmaniasis is a neglected tropical disease caused by the parasite of the genus Leishmania. About 13 million people are infected worldwide, and it is estimated that 350... 相似文献