全文获取类型
收费全文 | 15924篇 |
免费 | 889篇 |
国内免费 | 157篇 |
专业分类
耳鼻咽喉 | 98篇 |
儿科学 | 334篇 |
妇产科学 | 250篇 |
基础医学 | 1781篇 |
口腔科学 | 411篇 |
临床医学 | 1372篇 |
内科学 | 4937篇 |
皮肤病学 | 211篇 |
神经病学 | 1578篇 |
特种医学 | 616篇 |
外科学 | 2276篇 |
综合类 | 43篇 |
预防医学 | 586篇 |
眼科学 | 134篇 |
药学 | 713篇 |
1篇 | |
中国医学 | 12篇 |
肿瘤学 | 1617篇 |
出版年
2023年 | 135篇 |
2022年 | 235篇 |
2021年 | 426篇 |
2020年 | 301篇 |
2019年 | 361篇 |
2018年 | 439篇 |
2017年 | 342篇 |
2016年 | 420篇 |
2015年 | 450篇 |
2014年 | 611篇 |
2013年 | 837篇 |
2012年 | 1211篇 |
2011年 | 1249篇 |
2010年 | 691篇 |
2009年 | 724篇 |
2008年 | 1093篇 |
2007年 | 1186篇 |
2006年 | 1065篇 |
2005年 | 1039篇 |
2004年 | 1021篇 |
2003年 | 844篇 |
2002年 | 747篇 |
2001年 | 128篇 |
2000年 | 94篇 |
1999年 | 133篇 |
1998年 | 140篇 |
1997年 | 128篇 |
1996年 | 93篇 |
1995年 | 86篇 |
1994年 | 65篇 |
1993年 | 76篇 |
1992年 | 60篇 |
1991年 | 69篇 |
1990年 | 47篇 |
1989年 | 29篇 |
1988年 | 32篇 |
1987年 | 36篇 |
1986年 | 44篇 |
1985年 | 32篇 |
1984年 | 32篇 |
1983年 | 32篇 |
1982年 | 20篇 |
1981年 | 19篇 |
1980年 | 19篇 |
1979年 | 11篇 |
1977年 | 10篇 |
1972年 | 9篇 |
1968年 | 9篇 |
1967年 | 11篇 |
1966年 | 12篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Massimo Bonacchi Edvin Prifti Massimo Maiani Gabriele Giunti Marzia Leacche 《European journal of cardio-thoracic surgery》2005,28(1):120-126
OBJECTIVE: The aim of this study was to evaluate the feasibility, safety and outcome of skeletonized bilateral internal mammary arteries (BIMA) in patients with unstable angina (UA) undergoing non-elective myocardial revascularization. METHODS: Between January 1997 and December 2003, 758 patients, mean age 62+/-12 years, underwent non-elective coronary artery bypass grafting (CABG) for unstable angina. Two hundred and five (27%) were operated emergently and 503 (73%) urgently. BIMA were employed in 320 (42%) patients (Group B) and isolated left IMA and/or saphenous vein grafts in the remaining 438 (58%) patients (Group M). RESULTS: In-hospital mortality (B = 5.9% and M = 5.3%), and perioperative myocardial infarction (B = 2.2%; M = 1.96%) were similar between the two groups (P = ns). Actuarial survival at 1, 3 and 7 years was 98.7, 97.5 and 96.2% in B and 99, 94.3 and 88.4% in M (P < 0.05 at 7 years follow-up). At 7 years follow-up, the event-free cardiac survival (92 vs. 87%, P = 0.021), angina-free survival (98.6 vs. 94%, P = 0.039), reoperation-free cardiac survival (98 vs. 95%, P = 0.04) and infarct-free cardiac survival (98.7 vs. 96%, P = 0.05) were better in Group B. Multivariate analysis identified age > 65 years (P = 0.02), LVEF < 35% (P = 0.01), > 1 ischemic irreversible area (P = 0.03) as independent predictors for late deaths, while the use of the LIMA (P=0.006) and both mammary arteries (P=0.001) decreased the risk of late deaths. CONCLUSIONS: The use of BIMA in non-elective CABG for UA is safe and effective. Mid-term outcome, however, are superior with improved freedom from cardiac death, from coronary reintervention and from myocardial infarction. 相似文献
102.
103.
Umberto Capitanio Federico Deho’ Paolo Dell’Oglio Alessandro Larcher Paolo Capogrosso Alessandro Nini Cristina Carenzi Massimo Freschi Alberto Briganti Andrea Salonia Francesco Montorsi Roberto Bertini 《World journal of urology》2016,34(8):1139-1145
Introduction
In renal cell carcinoma (RCC), lymph node status at preoperative imaging is affected by a non-negligible false-positive rate. We aimed to investigate which factors are related to a concordance between clinical suspicion and pathological confirmation of lymph node invasion (LNI).Methods
At a single tertiary care institution, 2954 RCC patients underwent either partial or radical nephrectomy. For the aim of the study, only clinically positive lymph node cases were included (cN1). Statistical analyses assessed the concordance between preoperative and pathological nodal status.Results
Preoperative axial CT scans revealed 424 (14.4 %) patients showing at least one enlarged lymph node suspected for LNI (cN1). All lymphadenopathies were removed at surgery, and LNI was pathologically confirmed (pN1) in 122 patients (28.8 %). When focusing the analyses on clinical characteristics (variables known before surgery), metastases at diagnosis [OR 3.0 (95 %1.9–4.8), p < 0.001] and tumor size [OR 1.1 (95 % 1.1–1.2), p < 0.001] were the two most informative predictors of concordance between clinical and pathological nodal status. Concordance was also more likely in patients with papillary type II tumors (55.6 %) relative to papillary type I (38.1 %), clear cell (27.7 %) and chromophobe (8.3 %) tumors. At multivariable analyses, none of the considered blood markers resulted to be independently associated with LNI.Conclusions
Roughly 70 % of patients showing a suspected lymph node preoperatively do not show LNI at the final pathological report. Among patients with clinically positive nodes, clinical tumor size and metastases at diagnosis represent the most informative and independent predictors of confirmed LNI at final pathology.104.
Prediction of occult lymph node metastasis in squamous cell carcinoma of the oral cavity and the oropharynx using peritumoral Prospero homeobox protein 1 lymphatic nuclear quantification 下载免费PDF全文
105.
Luciana Ghio Mariano Ferraresso Graziella Zacchello Luisa Murer Fabrizio Ginevri Mirco Belingheri Licia Peruzzi Franco Zanon Francesco Perfumo Luisa Berardinelli Silvia Tirelli Luca Dello Strologo Iris Fontana Umberto Valente Massimo Cardillo Alberto Edefonti 《Clinical transplantation》2009,23(2):264-270
Abstract: This longitudinal study assessed the influence of post-transplant clinical and therapeutic variables in 50 kidney transplant recipients aged 2–19 yr receiving a triple immunosuppressive regimen consisting of cyclosporine microemulsion (CsA), steroids and MMF (300–400 mg/m2 body surface area twice daily), the full pharmacokinetic profile (10 points) of which was investigated on post-transplant days 6, 30, 180 and 360. Total plasma MPA was measured by Enzyme Multiplied Immunoassay Technique. CsA therapeutic drug monitoring (TDM) was performed via C2 blood monitoring, while MPA TDM via C0. MPA Cmax, tmax, AUC0-12 and AUC0-4 pharmacokinetic profile changed significantly during the first post-transplant year. C0 was a poor predictor of the total MPA exposure [as measured by the area under the concentration-time curve AUC)], while a truncated AUC was a good surrogate of the 12-h profile (r = 0.91; p < 0.001) Graft function and cyclosporine therapy influenced MPA pharmacokinetics, as shown by the univariate and multivariate analyses. We conclude that because after transplantation MPA exposure varied over time, a strict TDM is advisable in the pediatric population. 相似文献
106.
Alberto Tagliafico Bianca Bignotti Giulio Tagliafico Simona Tosto Alessio Signori Massimo Calabrese 《The British journal of radiology》2015,88(1056)
Objective:
To evaluate quantitative measurements of background parenchymal enhancement (BPE) on breast MRI and compare them with observer-based scores.Methods:
BPE of 48 patients (mean age: 48 years; age range: 36–66 years) referred to 3.0-T breast MRI between 2012 and 2014 was evaluated independently and blindly to each other by two radiologists. BPE was estimated qualitatively with the standard Breast Imaging Reporting and Data System (BI-RADS) scale and quantitatively with a semi-automatic and an automatic software interface. To assess intrareader agreement, MRIs were re-read after a 4-month interval by the same two readers. The Pearson correlation coefficient (r) and the Bland–Altman method were used to compare the methods used to estimate BPE. p-value <0.05 was considered significant.Results:
The mean value of BPE with the semi-automatic software evaluated by each reader was 14% (range: 2–79%) for Reader 1 and 16% (range: 1–61%) for Reader 2 (p > 0.05). Mean values of BPE percentages for the automatic software were 17.5 ± 13.1 (p > 0.05 vs semi-automatic). The automatic software was unable to produce BPE values for 2 of 48 (4%) patients. With BI-RADS, interreader and intrareader values were κ = 0.70 [95% confidence interval (CI) 0.49–0.91] and κ = 0.69 (95% CI 0.46–0.93), respectively. With semi-automated software, interreader and intrareader values were κ = 0.81 (95% CI 0.59–0.99) and κ = 0.85 (95% CI 0.43–0.99), respectively. BI-RADS scores correlated with the automatic (r = 0.55, p < 0.001) and semi-automatic scores (r = 0.60, p < 0.001). Automatic scores correlated with the semi-automatic scores (r = 0.77, p < 0.001). The mean percentage difference between automatic and semi-automatic scores was 3.5% (95% CI 1.5–5.2).Conclusion:
BPE quantitative evaluation is feasible with both semi-automatic and automatic software and correlates with radiologists'' estimation.Advances in knowledge:
Computerized BPE quantitative evaluation is feasible with both semi-automatic and automatic software. Computerized BPE quantitative scores correlate with radiologists'' estimation. 相似文献107.
Giovanni Foti Letizia Boninsegna Massimo Falconi Roberto Pozzi Mucelli 《La Radiologia medica》2013,118(7):1082-1101
Purpose
This study was done to compare the diagnostic accuracy of multidetector computed tomography (MDCT) and magnetic resonance imaging (MRI) in the preoperative assessment of nonfunctioning pancreatic endocrine tumours (NFPET).Materials and methods
Fifty-one patients (25 men, 26 women; mean age, 52 years), preoperatively investigated by both MDCT and MRI and subsequently operated on with a histological diagnosis of NFPET, were included in this study. MDCT and MRI accuracy in evaluating location, size, margins, baseline density/signal intensity, structure, pattern of enhancement, peak enhancement phase, involvement of main pancreatic duct, involvement of adjacent organs, infiltration of peritumoural vessels, involvement of locoregional lymph nodes, and liver metastases was compared using Pearson correlation, Mann-Whitney and chi-square tests. A value of p<0.05 was considered statistically significant.Results
MDCT and MRI had similar accuracy in assessing size, margins, baseline density/signal intensity, structure, pattern of enhancement, peak enhancement phase, involvement of main pancreatic duct, involvement of adjacent organs, involvement of locoregional lymph nodes, and liver metastases (p>0.05). MDCT was superior to MRI in evaluating the infiltration of peritumoural vessels (p=0.025).Conclusions
MDCT performed better than MRI in assessing vascular involvement and should be considered the best imaging tool for preoperative evaluation of NFPET. 相似文献108.
Massimo De Filippo Luca Saba Giorgio Concari Rita Nizzoli Lilia Ferrari Marcello Tiseo Andrea Ardizzoni Nicola Sverzellati Ilaria Paladini Chiara Ganazzoli Luca Maria Sconfienza Giampaolo Carrafiello Luca Brunese Eugenio Annibale Genovese Luca Ampollini Paolo Carbognani Michele Rusca Maurizio Zompatori Cristina Rossi 《La Radiologia medica》2013,118(7):1071-1081
Purpose
The aim of this study was to analyse factors predicting the diagnostic accuracy of computed tomography (CT)-guided transthoracic fine-needle aspiration (TTFNA) for solid noncalcified, subsolid and mixed pulmonary nodules, with particular attention to those responsible for false negative results with a view to suggesting a method for their correction.Materials and methods
From January 2007 to March 2010, we retrospectively reviewed the CT images of 198 patients of both sexes (124 males and 74 females; mean age, 70 years; range age, 44–90) used for the guidance of TTFNA of pulmonary nodules. Aspects considered were: lesion size and density, distance from the pleura, and lesion site. Multiplanar reformatted images (MPR) were retrospectively obtained in the sagittal and axial oblique planes relative to needle orientation.Results
The overall diagnostic accuracy of TTFNA CTguided biopsy was 86% for nodules between 0.7 and 3 cm, 83.3% for those between 0.7 and 1.5 cm, and 92% for those between 2 and 3 cm. Accuracy was 95.1% for solid pulmonary nodules, 84.6% for mixed nodules, and 66.6% for subsolid nodules. The diagnostic accuracy of CT-guided TTFNA in relation to the distance between the nodule and the pleural plane was 95.6% for lesions adhering to the pleura and 83.5% for central ones. The diagnostic accuracy was 84.2% for the pulmonary upper lobe nodules, 85.3% for the lower lobe and 90.9% for those in the lingula and middle lobe. In 75% of false negative and inadequate/insufficient cases the needle was found to lie outside the lesion, after reconstruction of the needle path by MPR.Conclusions
The positive predictive factors of CT-guided TTFNA are related to the nodule size, density and distance from the pleural plane. The most common negative predictive factor of CT-guided TTFNA is the wrong position of the needle tip, as observed in the sagittal and axial oblique sections of the MPR reconstructions. The diagnostic accuracy of CT-guided TTFNA can therefore be improved by using the MPR technique to plan the needle path during the FNA procedure. 相似文献109.
Leonardo Pace Pasquale Perrone-Filardi Giovanni Storto Anna Maria Della Morte Santo Dellegrottaglie Mariella Prastaro Teresa Crisci Maria Paola Ponticelli Federico Piscione Massimo Chiariello Marco Salvatore 《European journal of nuclear medicine and molecular imaging》2000,27(12):1740-1746
Accurate assessment of myocardial viability permits selection of patients who would benefit from myocardial revascularization. Currently, rest-redistribution thallium-201 scintigraphy and low-dose dobutamine echocardiography are among the most used techniques for the identification of viable myocardium. Thirty-one consecutive patients (all men, mean age 60NJ years) with chronic coronary artery disease and reduced left ventricular ejection fraction (31%lj%) were studied. Rest 201Tl single-photon emission tomography (SPET), low-dose dobutamine echocardiography and radionuclide angiography were performed before revascularization. Radionuclide angiography and echocardiography were repeated after revascularization. An a/dyskinetic segment was considered viable on 201Tl SPET when tracer uptake was >65%, while improvement on low-dose dobutamine echocardiography was considered a marker of viability. Increase in global ejection fraction was considered significant at ̓%. In identifying viable segments, rest 201Tl SPET showed higher sensitivity than low-dose dobutamine echocardiography (72% vs 53%, P<0.05), while specificity was not significantly different (86% vs 88%). In 17 patients, global ejection fraction increased ̓% (group 1) while in 14 it did not (group 2). A higher number of a/dyskinetic segments were viable on 201Tl SPET in group 1 than in group 2 (2.6ǃ.9 vs 0.6ǃ.2, P<0.005), while no significant differences were observed on low-dose dobutamine echocardiography (1.7ǃ.6 vs 1.1ǃ.6). A significant correlation was found between the number of a/dyskinetic segments viable on 201Tl SPET and post-revascularization changes in ejection fraction (r=0.52, P<0.05), but such a correlation was not observed for low-dose dobutamine echocardiography. Using as the cut-off the presence of at least one viable a/dyskinetic segment, rest 201Tl SPET had a higher sensitivity (82% vs 53%, P=0.07) and showed a trend towards higher accuracy and specificity (77% vs 58%, and 71% vs 64%, respectively) as compared with low-dose dobutamine echocardiography. In conclusion, these findings suggest that when severely reduced global function is present, rest 201Tl SPET evaluation of viability is more accurate than low-dose dobutamine echocardiography for the identification of patients who will benefit most from revascularization. 相似文献
110.
Sarzo G Finco C Parise P Vecchiato M Savastano S Luongo B Degregori S Bocus P Marino F Poletti A De Lazzari F Merigliano S 《Chirurgia italiana》2005,57(6):789-798
Colitis cystica profunda is a rare intestinal lesion. Because of its clinical expression (rectorrhagia, mucorrhea and abdominal pain) and the way it appears to current imaging techniques this disease presents features which can be associated with colon neoplasm. Its diagnosis has to be confirmed histologically, and its etiology remains unclear. The following is a case report of colitis cystica profunda recurring 20 years after a first episode in a white woman, who had had an anterior resection of the sigmoid colon and upper rectum to deal with a colitis cystica profunda-induced stenosis of the sigmoid colon and at 41 underwent the transanal removal of a polypoid lesion. A review of 20 cases in the literature showed that colitis cystica profunda has a predilection for the male and generally affects the medial and lower rectum and the sigmoid colon. The literature also confirmed the association with ulcerative rectocolitis, Crohn's disease and rectal prolapse. The type of treatment varies from surgical, medical, and endoscopic to no treatment at all. 相似文献