全文获取类型
收费全文 | 73118篇 |
免费 | 4378篇 |
国内免费 | 1091篇 |
专业分类
耳鼻咽喉 | 670篇 |
儿科学 | 1659篇 |
妇产科学 | 1870篇 |
基础医学 | 8289篇 |
口腔科学 | 2244篇 |
临床医学 | 6033篇 |
内科学 | 18168篇 |
皮肤病学 | 1132篇 |
神经病学 | 6775篇 |
特种医学 | 2735篇 |
外国民族医学 | 2篇 |
外科学 | 10071篇 |
综合类 | 2193篇 |
现状与发展 | 1篇 |
一般理论 | 8篇 |
预防医学 | 3849篇 |
眼科学 | 1009篇 |
药学 | 5399篇 |
8篇 | |
中国医学 | 1077篇 |
肿瘤学 | 5395篇 |
出版年
2023年 | 571篇 |
2022年 | 1426篇 |
2021年 | 2329篇 |
2020年 | 1439篇 |
2019年 | 1683篇 |
2018年 | 2015篇 |
2017年 | 1551篇 |
2016年 | 1705篇 |
2015年 | 2098篇 |
2014年 | 2799篇 |
2013年 | 3573篇 |
2012年 | 4973篇 |
2011年 | 5162篇 |
2010年 | 3050篇 |
2009年 | 2744篇 |
2008年 | 4420篇 |
2007年 | 4533篇 |
2006年 | 4167篇 |
2005年 | 4059篇 |
2004年 | 3645篇 |
2003年 | 3151篇 |
2002年 | 2885篇 |
2001年 | 1593篇 |
2000年 | 1446篇 |
1999年 | 1402篇 |
1998年 | 676篇 |
1997年 | 518篇 |
1996年 | 535篇 |
1995年 | 413篇 |
1994年 | 377篇 |
1993年 | 297篇 |
1992年 | 758篇 |
1991年 | 649篇 |
1990年 | 603篇 |
1989年 | 614篇 |
1988年 | 522篇 |
1987年 | 462篇 |
1986年 | 448篇 |
1985年 | 353篇 |
1984年 | 339篇 |
1983年 | 263篇 |
1982年 | 188篇 |
1981年 | 138篇 |
1979年 | 236篇 |
1978年 | 154篇 |
1977年 | 142篇 |
1974年 | 137篇 |
1973年 | 145篇 |
1972年 | 132篇 |
1971年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
Gianluca Gambarini Lucila Piasecki Gabriele Miccoli Gianfranco Gaimari Roberto Di Giorgio Dario Di Nardo Adham A Azim Luca Testarelli 《Australian endodontic journal : the journal of the Australian Society of Endodontology Inc》2019,45(2):154-162
This study evaluated the effect of new motions of the motor TriAuto ZX2 on the cyclic fatigue of endodontic instruments. Vortex Blue 35.06 instruments were divided into four groups (n = 10) and tested for fatigue in a curved artificial canal (90° and 2 mm radius) using the following motions: continuous rotation (CR), Optimum Torque Reverse (OTR) set at 180° and the Optimum Glide Path (OGP), which was tested at 90° and 240°. The time to fracture (TTF) and the lengths of the fractured fragments were recorded. The mean TTF was significantly different among the groups (anova , P < 0.05): OGP 90° (213.39 ± 27.45), OTR 180° (121.24 ± 17.03), OGP 240° (45.24 ± 5.61) and CR (8.43 ± 1.27). Weibull analysis confirmed the shortest life expectancy for CR and the longest survival for OGP at 90°. The resistance to fatigue was affected by motions and pre‐set angles. The proprietary movements that are currently available for endodontic instruments were classified according to their kinematics. 相似文献
43.
44.
Roberto De la Plaza Llamas Jos M Ramia 《World journal of gastroenterology : WJG》2020,26(21):2682-2690
Postoperative complications(PC) are a basic health outcome, but no surgery service in the world records and/or audits the PC associated with all the surgical procedures it performs. Most studies that have assessed the cost of PC suffer from poor quality and a lack of transparency and consistency. The payment system in place often rewards the volume of services provided rather than the quality of patients' clinical outcomes. Without a thorough registration of PC, the economic costs involved cannot be determined. An accurate, reliable appraisal would help identify areas for investment in order to reduce the incidence of PC,improve surgical results, and bring down the economic costs. This article describes how to quantify and classify PC using the Clavien-Dindo classification and the comprehensive complication index, discusses the perspectives from which economic evaluations are performed and the minimum postoperative follow-up established, and makes various recommendations. The availability of accurate and impartially audited data on PC will help reduce their incidence and bring down costs. Patients, the health authorities, and society as a whole are sure to benefit. 相似文献
45.
46.
F Sebastiano G Di Gennaro V Esposito A Picardi R Morace A Sparano A Mascia C Colonnese G Cantore P P Quarato 《Clinical neurophysiology》2006,117(2):341-347
OBJECTIVES: To evaluate a novel method for localization of subdural electrodes in presurgical assessment of patients with drug-resistant focal epilepsy. METHODS: We studied eight consecutive patients with posterior epilepsy in whom subdural electrodes were implanted for presurgical evaluation. Electrodes were detected on post-implantation brain CT scans through a semiautomated procedure based on a MATLAB routine. Then, post-implantation CT scans were fused with pre-implantation MRI to localize the electrodes in relation to the underlying cortical structures. The reliability of this procedure was tested by comparing 3D-rendered MR images of the electrodes with electrode position as determined by intraoperative digital photography. RESULTS: In each patient, all electrodes could be correctly localized and visualized in a stereotactic space, thus allowing optimal surgery planning. The agreement between the procedure-generated images and the digital photographs was good according to two independent raters. The mean mismatch between the 3D images and the photographs was 2 mm. CONCLUSIONS: While our findings need confirmation on larger samples including patients with anterior epilepsy, this procedure allowed to localize subdural electrodes and to establish the spatial relationship of each electrode to the underlying brain structure, either normal or damaged, on brain convessity, basal and medial cortex. SIGNIFICANCE: Being simple, rapid, unexpensive, and reliable, this procedure holds promise to be useful to optimize epilepsy surgery planning. 相似文献
47.
Roberto Manfredi Sergio Sabbatani Leonardo Calza 《The Brazilian journal of infectious diseases》2007,11(6):605-609
A patient with HIV infection developed the first episode of AIDS-defining opportunism (severe Candida albicans esophagitis) with an underlying CD4+ lymphocyte count of 1,025 cells/microL. After treatment with a highly active antiretroviral therapy (HAART), taken with insufficient compliance and leaving a residual viral load, our patient suffered from two relapses of esophageal candidiasis, which occurred three months and seven years later, when his CD4+ lymphocyte count was 930 and 439 cells/microL, respectively, and a viral load slightly above 10(4) copies/mL was still present. Also in the HAART era, Candida esophagitis remains one of the most common AIDS-defining diseases, but a presentation with a concurrent CD4+ count above 1,000 cells/microL remains a rare exception, as well as the two isolated, subsequent relapses, occurred with a CD4+ count ranging from 439 to 930 cells/microL, and a residual HIV viremia due to insufficient adherence to the prescribed HAART regimens. Our case report represents the opportunity to revisit the epidemiology and, especially, the pathogenesis of this opportunistic fungal complication in HIV-infected patients and in other subjects at risk, on the ground of an extensive literature review, and to explore possible alternative supporting factors other than the crude absolute CD4+ lymphocyte count, with emphasis on the possible role of a persisting HIV viremia, and other potential contributing factors. Clinicians engaged with immunocompromised patients and subjects with HIV disease, should be aware that a Candida esophagitis may occur and relapse also when the cell-mediated immunity, as measured by a simple CD4+ cell count, do not show relevant abnormalities. 相似文献
48.
BACKGROUND/PURPOSE: Sensitive skin is a condition associated with reduced tolerance to environmental factors and/or the application of topical products, such as cosmetics. Its pathophysiology has not been fully elucidated and few data are available on its prevalence. The aim of this study was to investigate possible correlation between objective sensitivity and skin surface microrelief. METHODS: During an epidemiological survey conducted for a campaign promoted by International Society of Plastic Dermatology in Italy, 243 adult healthy subjects of both sexes with no evident dermatological disorder but positive to the lactic acid stinging test, were submitted to cyanoacrylate stratum corneum stripping from the volar forearm for the determination of the irregularity of the skin surface microrelief (irregularity skin index (ISI)). RESULTS: A significant correlation was found between intensity of symptoms in stingers and ISI (r(s)=-0.47; P<0.001). CONCLUSION: Sensitive skin is common in the healthy population. ISI can contribute towards the identification of subjects with sensitive skin and the development of more specific skin treatments for this prevalent condition. 相似文献
49.
Daniela Brizzolara Anna Chilosi Paola Cipriani Gloria Di Filippo Filippo Gasperini Sara Mazzotti Chiara Pecini Pierluigi Zoccolotti 《Cognitive and behavioral neurology》2006,19(3):141-149
OBJECTIVE: The study aims to verify whether phonologic and rapid automatized naming (RAN) deficits are present and associated in Italian dyslexic children and whether they differentially affect dyslexics with and without a history of previous language delay (LD). BACKGROUND: According to the phonologic core deficit hypothesis, dyslexia may stem from impairment of the representation and manipulation of phonemes and may be closely associated with oral language deficits. However, deficits in tasks not requiring fine-grained phonologic representations, such as RAN, have also been described in dyslexic children. METHODS: Thirty-seven children were selected on the basis of a reading deficit and were assigned to 2 groups according to whether or not they had a history of early LD as determined retrospectively by parental report. A battery of reading and writing, verbal working memory, metaphonologic, RAN, and visual search tests were administered. RESULTS: RAN deficits were shared by most dyslexics (with and without a history of LD), whereas phonologic deficits were mainly associated with a previous LD. This last condition did not result in a more profound impairment of reading and writing decoding skills. CONCLUSION: In a shallow orthography such as Italian, RAN, not phonologic deficits, may represent the main cognitive marker of developmental dyslexia. 相似文献
50.