全文获取类型
收费全文 | 4404篇 |
免费 | 521篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 69篇 |
儿科学 | 150篇 |
妇产科学 | 119篇 |
基础医学 | 630篇 |
口腔科学 | 145篇 |
临床医学 | 500篇 |
内科学 | 838篇 |
皮肤病学 | 26篇 |
神经病学 | 336篇 |
特种医学 | 180篇 |
外科学 | 479篇 |
综合类 | 169篇 |
一般理论 | 3篇 |
预防医学 | 508篇 |
眼科学 | 54篇 |
药学 | 281篇 |
中国医学 | 6篇 |
肿瘤学 | 443篇 |
出版年
2021年 | 54篇 |
2020年 | 39篇 |
2019年 | 59篇 |
2018年 | 90篇 |
2017年 | 58篇 |
2016年 | 77篇 |
2015年 | 70篇 |
2014年 | 92篇 |
2013年 | 147篇 |
2012年 | 198篇 |
2011年 | 187篇 |
2010年 | 149篇 |
2009年 | 123篇 |
2008年 | 163篇 |
2007年 | 183篇 |
2006年 | 188篇 |
2005年 | 201篇 |
2004年 | 135篇 |
2003年 | 157篇 |
2002年 | 154篇 |
2001年 | 132篇 |
2000年 | 165篇 |
1999年 | 141篇 |
1998年 | 65篇 |
1997年 | 60篇 |
1996年 | 60篇 |
1995年 | 65篇 |
1994年 | 63篇 |
1993年 | 50篇 |
1992年 | 130篇 |
1991年 | 108篇 |
1990年 | 112篇 |
1989年 | 102篇 |
1988年 | 98篇 |
1987年 | 81篇 |
1986年 | 77篇 |
1985年 | 86篇 |
1984年 | 62篇 |
1983年 | 53篇 |
1982年 | 46篇 |
1981年 | 37篇 |
1980年 | 37篇 |
1979年 | 62篇 |
1978年 | 46篇 |
1977年 | 33篇 |
1976年 | 34篇 |
1974年 | 33篇 |
1973年 | 33篇 |
1972年 | 34篇 |
1970年 | 34篇 |
排序方式: 共有4936条查询结果,搜索用时 17 毫秒
131.
BO Motayo PA Akinduti FA Adeyakinu PO Okerentugba JC Nwanze CC Onoh HC Innocent-Adiele IO Okonko 《African health sciences》2013,13(4):1091-1097
Background
The increased reports of ESBL dissemination from various centres in south western, Nigeria and the recent emergence of carbapenem resistant bacteria prompted the conception of this study.Objectives
To demonstrate the relationship between high molecular weight plasmids and the expression of antibiotic multi-resistance including ESBL and carbapenemase.Methods
We investigated 97 isolates of selected organisms consisting of 67 E. coli and 30 Klebseilla spp for the presence of plasmids expressing ESBL including carbapenem-hydrolysing enzymes. Beta-lactamase was determined using acidometric method, while ESBL and carbapenemase activity was determined using the double-disk diffusion test as well as the Modified Hodge test (MHT). Plasmid profiles of ESBL and carbapenemase positive isolates were determined according to standard protocols.Results
An ESBL prevalence rate of 21.6% and carbapenem- resistance rate of 9.3% was recorded. Antibiotic susceptibility profile of ESBL isolates showed 100.0% resistance against Amoxicillin, Cotrimoxazole and Erythromycin. Moderate susceptibility was recorded against the Quinolone class of antibiotics; Meropenem remained the most active antibiotic against ESBL isolates with 62.5% against E. coli and 60% against K. pneumoniae. The plasmid profiles of our study isolates ranged from 11.8kbp to 35.5kbp.Conclusion
Due to the relationship between high molecular weight plasmids and multi-drug resistance, we hereby recommend regular molecular surveillance of this form in our study setting. 相似文献132.
YENN‐JIANG LIN M.D. SHIH‐LIN CHANG M.D. LI‐WEI LO M.D. YU‐FENG HU M.D. KAZUYOSHI SUENARI M.D. CHENG‐HUNG LI M.D. TZE‐FAN CHAO M.D. FA‐PO CHUNG M.D. JO‐NAN LIAO M.D. BENY HARTONO M.D. HAN‐WEN TSO Ph.D. HSUAN‐MING TSAO M.D. JIN‐LONG HUANG M.D. TSAIR KAO Ph.D. SHIH‐ANN CHEN M.D. 《Journal of cardiovascular electrophysiology》2012,23(11):1155-1162
Modified Pulmonary Vein Isolation in AF Ablation. Introduction: Pulmonary vein isolation (PVI) is the primary ablation therapy in patients with atrial fibrillation (AF). We hypothesized that high dominant frequency (DF) sites (AF nests during sinus rhythm [SR]) adjacent to the PV ostia are associated with the atrial substrate that maintains AF, and PVI incorporating the high‐frequency AF nests may have a higher efficacy. Methods and Results: In a prospective and randomized comparison, 126 symptomatic paroxysmal AF patients that underwent PVI were enrolled. We compared the efficacy of a modified PVI (ablation line: 1.0–1.5 cm from the PV ostium with encircling the AF nests [spectral analysis with DF >70 Hz during SR, Group II]) versus the anatomy‐guided conventional PVI (Group I). In Group II, the DF value along the PV ostium was lower than 70 Hz after the PVI. The primary endpoint was the freedom from symptomatic atrial arrhythmias after a single procedure. We also followed the autonomic function by a time‐domain analysis of the heart rate variability. In both groups, AF nests were observed and electric isolation was successfully obtained in all patients. With a mean duration of 16 ± 6.1 months of follow‐up, Group II had a higher single procedure efficacy without drugs (78.7% vs 66.1%, log‐rank test: P = 0.02), and fewer repeat procedures (6.6% vs 23%; P = 0.04), as compared to Group I. Conclusion: PVI incorporating the high frequency AF nests adjacent to the PV ostia had a better single procedure efficacy. (J Cardiovasc Electrophysiol, Vol. 23, pp. 1155–1162, November 2012) 相似文献
133.
134.
Total body volume is an important health metric used to measure body density, shape, and multicompartmental body composition but is currently only available through underwater weighing or air displacement plethysmography (ADP). The objective of this investigation was to derive an accurate body volume from dual-energy X-ray absorptiometry (DXA)–reported measures for advanced body composition models. Volunteers received a whole body DXA scan and an ADP measure at baseline (N = 25) and 6 mo (N = 22). Baseline measures were used to calibrate body volume from the reported DXA masses of fat, lean, and bone mineral content. A second population (N = 385) from the National Health and Nutrition Examination Survey was used to estimate the test-retest precision of regional (arms, legs, head, and trunk) and total body volumes. Overall, we found that DXA-volume was highly correlated to ADP-volume (R2 = 0.99). The 6-mo change in total DXA-volume was highly correlated to change in ADP-volume (R2 = 0.98). The root mean square percent coefficient of variation precision of DXA-volume measures ranged from 1.1% (total) to 3.2% (head). We conclude that the DXA-volume method can measure body volume accurately and precisely, can be used in body composition models, could be an independent health indicator, and is useful as a prospective or retrospective biomarker of body composition. 相似文献
135.
John A. Shepherd Sanford Baim John P. Bilezikian John T. Schousboe 《Journal of clinical densitometry》2013,16(4):489-495
There have been many scientific advances in measurement of fat and lean body mass as determined by dual-energy X-ray absorptiometry (DXA). The International Society for Clinical Densitometry (ISCD) convened a Position Development Conference (PDC) on the use of DXA for body composition measurement. Previously, no guidelines to the use of DXA for body composition existed. The recommendations pertain to clinically relevant issues regarding DXA indications of use, acquisition, analysis, quality control, interpretation, and reporting were addressed. The topics and questions for consideration were developed by the ISCD Board of Directors and the Scientific Advisory Committee and were designed to address the needs of clinical practitioners. Three Task Forces were created and assigned these questions and asked to conduct comprehensive literature reviews. The Task Forces included participants from 6 countries and a variety of interests including academic institutions, private clinics, and industry. Reports with proposed Position Statements were then presented to an international panel of experts with backgrounds in DXA and bone densitometry and a variety of fields that use body composition measures. The PDC was held in Tampa, FL, contemporaneously with the Annual Meeting of the ISCD, March 21 through March 23, 2013. This report describes the methodology of the 2013 ISCD Body Composition PDC and summarizes the results. Three separate articles in this issue will detail the rationale, discussion, and additional research topics for each question the Task Forces addressed. 相似文献
136.
Darren Shepherd Yvonne Belessis Tamarah Katz John Morton Penny Field Adam Jaffe 《Journal of cystic fibrosis》2013,12(2):177-182
ObjectivesTo determine the safety and efficacy of stoss therapy on vitamin D levels over a 12 month period in children with cystic fibrosis and vitamin D deficiency (< 75 nmol/L).Study designRetrospective chart review of 142 paediatric CF patients from 2007 till 2011.ResultsThirty eight children received stoss therapy and 37 children with vitamin D deficiency were not treated and served as a control group. The stoss treated group had a significant and sustained increase in 25-hydroxyvitamin D levels measured at 1, 3, 6 and 12 months post treatment compared to controls (94.82 ± 41.0 nmol/L, p = 0.001; 81.54 ± 24.6 nmol/L, p = 0.001; 92.18 ± 36.5 nmol/L, p = 0.008 and 64.6 ± 20.0 nmol/L, p = 0.006 respectively). At 12 months post intervention, the mean difference in vitamin D levels from baseline between the stoss treated group and controls was significant at 15 nmol/L compared to 5 nmol/L (p = 0.038).ConclusionStoss therapy effectively achieves and maintains levels of 25-hydroxyvitamin D greater than 75 nmol/L over 12 months. 相似文献
137.
Saeed Asadollahi David Shepherd Raphael C. Hau 《International journal of surgery case reports》2013,4(8):748-752
INTRODUCTIONGaleazzi fracture associated with ipsilateral posterior elbow dislocation and radial head fracture is a rare pattern of injury. Few reports exist that describes this injury pattern and its treatment. We describe a case report of simultaneous occurrence of Galeazzi fracture and ipsilateral dislocation of elbow.PRESENTATION OF CASEA 58 year-old female presented with Galeazzi fracture and posterior elbow dislocation associated with radial head fracture of left upper extremity. This was managed with closed reduction of the elbow, open reduction and internal fixation of the radial shaft fracture and K-wire stabilisation of the unstable distal radioulnar joint. Prophylactic fasciotomy was performed. At 10 months follow-up, the outcome was favourable with the American shoulder and elbow surgeon score of 92 and the disabilities of the arm, shoulder and hand score of 18.DISCUSSIONThe presumed mechanism of the injury was a forceful axial loading of a hyperpronated forearm and extended elbow. Our literature review shows that this pattern of injury occurs as a result of high energy trauma in young individuals, and successful outcome can be achieved by addressing each component of this complex injury individually.CONCLUSIONSimultaneous occurrence of elbow dislocation and Galeazzi fracture seems to be the result of extreme axial force and unique position of upper extremity at the time of impact. Individualised approach to each component of this injury can result in favourable outcome. 相似文献
138.
139.
Kate Fox Hamish Meffin Owen Burns Carla J. Abbott Penelope J. Allen Nicholas L. Opie Ceara McGowan Jonathan Yeoh Arman Ahnood Chi D. Luu Rosemary Cicione Alexia L. Saunders Michelle McPhedran Lisa Cardamone Joel Villalobos David J. Garrett David A. X. Nayagam Nicholas V. Apollo Kumaravelu Ganesan Mohit N. Shivdasani Alastair Stacey Mathilde Escudie Samantha Lichter Robert K. Shepherd Steven Prawer 《Artificial organs》2016,40(3):E12-E24
Successful visual prostheses require stable, long‐term attachment. Epiretinal prostheses, in particular, require attachment methods to fix the prosthesis onto the retina. The most common method is fixation with a retinal tack; however, tacks cause retinal trauma, and surgical proficiency is important to ensure optimal placement of the prosthesis near the macula. Accordingly, alternate attachment methods are required. In this study, we detail a novel method of magnetic attachment for an epiretinal prosthesis using two prostheses components positioned on opposing sides of the retina. The magnetic attachment technique was piloted in a feline animal model (chronic, nonrecovery implantation). We also detail a new method to reliably control the magnet coupling force using heat. It was found that the force exerted upon the tissue that separates the two components could be minimized as the measured force is proportionately smaller at the working distance. We thus detail, for the first time, a surgical method using customized magnets to position and affix an epiretinal prosthesis on the retina. The position of the epiretinal prosthesis is reliable, and its location on the retina is accurately controlled by the placement of a secondary magnet in the suprachoroidal location. The electrode position above the retina is less than 50 microns at the center of the device, although there were pressure points seen at the two edges due to curvature misalignment. The degree of retinal compression found in this study was unacceptably high; nevertheless, the normal structure of the retina remained intact under the electrodes. 相似文献
140.
Lindsay C. Turner Erin S. Lavelle Jonathan P. Shepherd 《International urogynecology journal》2016,27(5):797-803