全文获取类型
收费全文 | 1986篇 |
免费 | 199篇 |
国内免费 | 7篇 |
专业分类
耳鼻咽喉 | 8篇 |
儿科学 | 56篇 |
妇产科学 | 15篇 |
基础医学 | 295篇 |
口腔科学 | 15篇 |
临床医学 | 136篇 |
内科学 | 480篇 |
皮肤病学 | 40篇 |
神经病学 | 137篇 |
特种医学 | 37篇 |
外科学 | 406篇 |
综合类 | 24篇 |
预防医学 | 206篇 |
眼科学 | 29篇 |
药学 | 116篇 |
中国医学 | 1篇 |
肿瘤学 | 191篇 |
出版年
2023年 | 6篇 |
2022年 | 16篇 |
2021年 | 45篇 |
2020年 | 19篇 |
2019年 | 47篇 |
2018年 | 53篇 |
2017年 | 35篇 |
2016年 | 31篇 |
2015年 | 47篇 |
2014年 | 59篇 |
2013年 | 86篇 |
2012年 | 136篇 |
2011年 | 152篇 |
2010年 | 101篇 |
2009年 | 79篇 |
2008年 | 134篇 |
2007年 | 134篇 |
2006年 | 141篇 |
2005年 | 118篇 |
2004年 | 122篇 |
2003年 | 98篇 |
2002年 | 105篇 |
2001年 | 25篇 |
2000年 | 16篇 |
1999年 | 18篇 |
1998年 | 53篇 |
1997年 | 30篇 |
1996年 | 25篇 |
1995年 | 20篇 |
1994年 | 9篇 |
1993年 | 14篇 |
1992年 | 13篇 |
1991年 | 19篇 |
1990年 | 15篇 |
1989年 | 7篇 |
1988年 | 12篇 |
1987年 | 9篇 |
1986年 | 15篇 |
1985年 | 11篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1980年 | 12篇 |
1978年 | 6篇 |
1977年 | 8篇 |
1976年 | 8篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1973年 | 4篇 |
1965年 | 5篇 |
排序方式: 共有2192条查询结果,搜索用时 15 毫秒
81.
Patricia C. Jost O. Hayes Griffith Roderick A. Capaldi Garret Vanderkooi 《Proceedings of the National Academy of Sciences of the United States of America》1973,70(2):480-484
Cytochrome oxidase (EC 1.9.3.1) isolated from beef-heart mitochondria with an appropriate phospholipid content forms vesicular structures. Lipid-protein interactions in this model membrane system were studied with the lipid spin label, 16-doxylstearic acid. As the phospholipid/protein ratio is varied, two spectral components are observed. At low phospholipid/protein ratios (=0.19 mg of phospholipid per mg of protein) the lipid spin label is highly immobilized. At higher phospholipid content an additional component characteristic of fluid lipid bilayers is evident. By summation of digitalized spectra and subsequent integration it was shown that all composite spectra could be approximated by assuming only two components are present, and that the amount of phospholipid bound to the protein is independent of the extent of the fluid bilayer region. The experimentally determined amount of phospholipid for maximum occupancy of protein-bound sites is about 0.2 mg of phospholipid per 1.0 mg of protein. Calculations show that this ratio is consistent with a single layer of phospholipid surrounding the protein complex. The data are interpreted as evidence for a boundary of immobilized lipid between the hydrophobic protein and adjacent fluid bilayer regions in this membrane model system. 相似文献
82.
83.
David M Raffel Robert A Koeppe Roderick Little Chia-Ning Wang Suyu Liu Larry Junck Mary Heumann Sid Gilman 《Journal of nuclear medicine》2006,47(11):1769-1777
Scintigraphic imaging with (123)I-metaiodobenzylguanidine ((123)I-MIBG) has demonstrated extensive losses of cardiac sympathetic neurons in idiopathic Parkinson's disease (IPD). In contrast, normal cardiac innervation has been observed in (123)I-MIBG studies of multiple-system atrophy (MSA) and progressive supranuclear palsy (PSP). Consequently, it has been hypothesized that cardiac denervation can be used to differentiate IPD from MSA and PSP. We sought to test this hypothesis by mapping the distribution of cardiac sympathetic neurons in patients with IPD, MSA, and PSP by using PET and (11)C-meta-hydroxyephedrine ((11)C-HED). Also, the relationship between cardiac denervation and nigrostriatal denervation was investigated by measuring striatal presynaptic monoaminergic nerve density with PET and (11)C-dihydrotetrabenazine ((11)C-DTBZ). METHODS: (11)C-HED and (11)C-DTBZ scans were obtained for patients with IPD (n = 9), MSA (n = 10), and PSP (n = 8) and for age-matched control subjects (n = 10). Global and regional measurements of (11)C-HED retention were obtained to assess the extent of cardiac sympathetic denervation. (11)C-DTBZ binding was measured in the caudate nucleus, anterior putamen, and posterior putamen. RESULTS: As expected, extensive cardiac denervation was observed in several of the patients with IPD. However, substantial cardiac denervation was also seen in some patients with MSA and PSP. (11)C-DTBZ studies demonstrated striatal denervation in all patients with IPD and in most patients with MSA and PSP. No correlation was found between cardiac (11)C-HED retention and striatal (11)C-DTBZ binding. CONCLUSION: Cardiac sympathetic denervation was found to occur not only in IPD but also in other movement disorders, such as MSA and PSP. This finding implies that scintigraphic detection of cardiac sympathetic denervation cannot be used independently to discriminate IPD from other movement disorders, such as MSA and PSP. Cardiac sympathetic denervation was not correlated with striatal denervation, suggesting that the pathophysiologic processes underlying cardiac denervation and striatal denervation occur independently in patients with parkinsonian syndromes. These findings provide novel information about central and peripheral denervation in patients with neurodegenerative disorders. 相似文献
84.
Gareth Crouch Nitesh D Dhanekula Karen Byth Emma Burn Sue Lynn Lau Lillias Nairn Liza Nery Jean Doyle Edward Graham Andrew Ellis Roderick J Clifton-Bligh Christian M Girgis 《Journal of bone and mineral research》2021,36(5):910-920
Atypical femur fractures (AFF) are a rare but serious complication of long-term bisphosphonate use. Although clearly defined by ASBMR criteria, a proportion of patients with AFFs may go unrecognized and the use of qualitative fracture criteria may lead to uncertainty in AFF diagnosis, with significant therapeutic implications. A score that rapidly and accurately identifies AFFs among subtrochanteric femur fractures using quantitative, measurable parameters is needed. In a retrospective cohort of 110 female patients presenting with AFFs or typical femur fractures (TFFs), multiple logistic regression and decision tree analysis were used to develop the Sydney AFF score. This score, based on demographic and femoral geometry variables, uses three dichotomized independent predictors and adds one point for each: (age ≤80 years) + (femoral neck width <37 mm) + (lateral cortical width at lesser trochanter ≥5 mm), (score, 0 to 3). In an independent validation set of 53 female patients at a different centre in Sydney, a score ≥2 demonstrated 73.3% sensitivity and 69.6% specificity for AFF (area under the receiver-operating characteristic curve [AUC] 0.775, SE 0.063) and remained independently associated with AFF after adjustment for bisphosphonate use. The Sydney AFF score provides a quantitative means of flagging female patients with atraumatic femur fractures who have sustained an AFF as opposed to a TFF. This distinction has clear management implications and may augment current ASBMR diagnostic criteria. © 2021 American Society for Bone and Mineral Research (ASBMR). 相似文献
85.
Reinier W.A. Spek Diederik P.J. Smeeing Linda van den Heuvel Marike C. Kokke Abhiram R. Bhashyam Johannes C. Kelder Egbert J.M.M. Verleisdonk Roderick M. Houwert Detlef van der Velde 《The Journal of foot and ankle surgery》2021,60(4):712-717
The incidence of geriatric ankle fractures is rising and the potential for complications is high in this population. Little is known about factors associated with increased postoperative complications after surgical fixation of ankle fractures in older-age patients. The purpose of this retrospective cohort study was to assess the epidemiology and risk factors for complications after surgically treated ankle fractures in geriatric patients. All patients who were 65 years or older and had a surgically treated ankle fracture were included. Pilon fractures, patients who were initially treated conservatively or who had less than 1 month of follow-up were excluded. Postoperative complications, demographic-, fracture- and surgical data of 282 patients were recorded from two level 2 trauma centers between 2012 and 2017. A total of 87 (30.9%) patients developed a complication, of which wound related complications were most frequently reported. Superficial and deep wound infections were observed in 27 (9.6%) and 18 (6.4%) patients, respectively. Multivariate regression analysis demonstrated increased age to be an independent predictive variable for the occurrence of postoperative complications (odds ratio 1.04; 95% confidence interval 1.00-1.09), while cast immobilization for more than 2 weeks was a protective factor for the development of wound related complications (odds ratio 0.34; 95% confidence interval 0.17-0.66). In conclusion, the incidence of postoperative complications among geriatric patients after surgical treatment of ankle fractures is high and patients should be informed accordingly. 相似文献
86.
Nicolas Mottet Roderick C.N. van den Bergh Erik Briers Thomas Van den Broeck Marcus G. Cumberbatch Maria De Santis Stefano Fanti Nicola Fossati Giorgio Gandaglia Silke Gillessen Nikos Grivas Jeremy Grummet Ann M. Henry Theodorus H. van der Kwast Thomas B. Lam Michael Lardas Matthew Liew Malcolm D. Mason Philip Cornford 《European urology》2021,79(2):243-262
ObjectiveTo present a summary of the 2020 version of the European Association of Urology (EAU)-European Association of Nuclear Medicine (EANM)-European Society for Radiotherapy and Oncology (ESTRO)-European Society of Urogenital Radiology (ESUR)-International Society of Geriatric Oncology (SIOG) guidelines on screening, diagnosis, and local treatment of clinically localised prostate cancer (PCa).Evidence acquisitionThe panel performed a literature review of new data, covering the time frame between 2016 and 2020. The guidelines were updated and a strength rating for each recommendation was added based on a systematic review of the evidence.Evidence synthesisA risk-adapted strategy for identifying men who may develop PCa is advised, generally commencing at 50 yr of age and based on individualised life expectancy. Risk-adapted screening should be offered to men at increased risk from the age of 45 yr and to breast cancer susceptibility gene (BRCA) mutation carriers, who have been confirmed to be at risk of early and aggressive disease (mainly BRAC2), from around 40 yr of age. The use of multiparametric magnetic resonance imaging in order to avoid unnecessary biopsies is recommended. When a biopsy is performed, a combination of targeted and systematic biopsies must be offered. There is currently no place for the routine use of tissue-based biomarkers. Whilst prostate-specific membrane antigen positron emission tomography computed tomography is the most sensitive staging procedure, the lack of outcome benefit remains a major limitation. Active surveillance (AS) should always be discussed with low-risk patients, as well as with selected intermediate-risk patients with favourable International Society of Urological Pathology (ISUP) 2 lesions. Local therapies are addressed, as well as the AS journey and the management of persistent prostate-specific antigen after surgery. A strong recommendation to consider moderate hypofractionation in intermediate-risk patients is provided. Patients with cN1 PCa should be offered a local treatment combined with long-term hormonal treatment.ConclusionsThe evidence in the field of diagnosis, staging, and treatment of localised PCa is evolving rapidly. The 2020 EAU-EANM-ESTRO-ESUR-SIOG guidelines on PCa summarise the most recent findings and advice for their use in clinical practice. These PCa guidelines reflect the multidisciplinary nature of PCa management.Patient summaryUpdated prostate cancer guidelines are presented, addressing screening, diagnosis, and local treatment with curative intent. These guidelines rely on the available scientific evidence, and new insights will need to be considered and included on a regular basis. In some cases, the supporting evidence for new treatment options is not yet strong enough to provide a recommendation, which is why continuous updating is important. Patients must be fully informed of all relevant options and, together with their treating physicians, decide on the most optimal management for them. 相似文献
87.
88.
Y. Raja Rampersaud Stephen J. Lewis J. Roderick Davey Rajiv Gandhi Nizar N. Mahomed 《The spine journal》2014,14(2):234-243
Background contextIt is well accepted that total hip and knee arthroplasty (THA/TKA) for osteoarthritis (OA) is associated with reliable and sustained improvements in postoperative health-related quality of life (HRQoL). Although several studies have demonstrated comparable outcomes with THA/TKA after surgical intervention for lumbar spinal stenosis (LSS), the sustainability of the outcome after LSS surgery compared with THA/TKA remains uncertain.PurposeThe primary purpose of this study is to assess whether improvements in HRQoL after surgical management of focal lumbar spinal stenosis (FLSS) with or without spondylolisthesis are sustainable over the long term compared with that of THA/TKA for OA.Study designSingle-center, retrospective, longitudinal matched cohort study of prospectively collected outcomes, with a minimum of 5-year follow-up (FU).Patient samplePatients who had primary one- to two-level spinal decompression with or without instrumented fusion for FLSS and THA/TKA for primary OA.Outcome measuresPostoperative change from baseline to last FU in Short-Form 36 physical component summary (PCS) and mental component summary (MCS) scores among groups was used as the primary outcome measure.MethodsAn age, sex-matched inception cohort of primary one- to two-level spinal decompression with or without instrumented fusion for FLSS (n=99) was compared with a cohort of primary THA (n=99) and TKA (n=99) for OA and followed for a minimum of 5 years. Linear regression was used for the primary analysis.ResultsMean (percent) FUs in months were 80.5+16.04 (79%), 94.6+16.62 (92%), and 80.6+16.84 (85%) for the FLSS, THA, and TKA cohorts, respectively, with a range of 5 to 10 years for all three cohorts. The number of patients who have undergone revision including those lost to FU for the FLSS, THA, and TKA cohorts were n=20 (20.2%, same site [n=7] and adjacent segment [n=13]) requiring 27 operations, n=3 (3%, same site) requiring 5 operations, and n=8 (8.1%, same site) requiring 12 operations, respectively (p<.01). The average time to first revision was 56/65/43 months, respectively. Mean postoperative PCS (p<.0001) and MCS (p<.02) scores improved significantly and were durable for all groups at the last FU. The mean changes from baseline PCS/MCS scores to last FU were 8.5/6.4, 12.3/7.0, and 8.3/4.9 for FLSS, THA, and TKA, respectively. Adjusting for baseline age, sex, body mass index, PCS score, and MCS score, there was a strong trend in favor of greater sustained change in the PCS score of THA over FLSS (p=.07) and TKA (p=.08). No difference was noted for change in PCS score between FLSS and TKA (p=.95). No differences were noted for change in MCS score among all three cohorts (p>.1).ConclusionsSignificant improvements in HRQoL after surgical treatment of FLSS with or without spondylolisthesis and hip and knee OA are sustained for a mean of 7 to 8 years, with a minimum of 5-year FU. Despite a higher revision rate, patients undergoing surgery for FLSS can expect a comparable long-term average improvement in HRQoL from baseline compared with their peers undergoing TKA and to a lesser extent THA. 相似文献
89.
Sabin J. Bozso Jeevan Nagendran Roderick G.G. MacArthur Michael W.A. Chu Bob Kiaii Ismail El-Hamamsy Raymond Cartier Ali Shahriari Michael C. Moon 《The Journal of thoracic and cardiovascular surgery》2019,157(5):1763-1771
Objectives
We describe the Canadian results of the Ascyrus Medical Dissection Stent (AMDS), a novel partially uncovered aortic arch hybrid graft implanted antegrade during hypothermic circulatory arrest to promote true lumen expansion and enhance aortic remodeling.Methods
From March 2017 to February 2018, 16 consecutive patients (66 ± 12 years; 38% female) presented with acute type A aortic dissections and underwent emergent surgical aortic repair with AMDS implantation. All patients presented with DeBakey I aortic dissection, with evidence of malperfusion in 50% (n = 8) of patients. All cases were performed under hypothermic circulatory arrest with an additional average duration for AMDS implantation time of 2.1 minutes.Results
All 16 device implantations were successful. Overall 30-day mortality was 6.3% (n = 1) and stroke occurred in 6.3% (n = 1) of cases. There was no incidence of device-related aortic injury or aortic arch branch vessel occlusion. During the follow-up period, 12 patients had completed at least 1 postoperative computed tomography scan. At initial follow-up computed tomography scan, complete or partial thrombosis, and remodeling of the aortic arch occurred in 91.7% of cases (n = 11/12) and in the proximal descending thoracic aorta, complete or partial thrombosis, and remodeling occurred in 91.7% (n = 11/12).Conclusions
Preliminary results suggest that the AMDS is a safe, feasible and reproducible adjunct to current surgical approaches for acute DeBakey I aortic dissection repair. Further, the AMDS manages malperfusion and promotes early positive remodeling in the aortic arch and distal dissected segments, with favorable FL closure rates at follow-up. Ongoing follow-up will provide additional insight into the long-term effects of the AMDS. 相似文献90.