全文获取类型
收费全文 | 6540篇 |
免费 | 277篇 |
国内免费 | 63篇 |
专业分类
耳鼻咽喉 | 43篇 |
儿科学 | 213篇 |
妇产科学 | 193篇 |
基础医学 | 720篇 |
口腔科学 | 112篇 |
临床医学 | 714篇 |
内科学 | 1791篇 |
皮肤病学 | 61篇 |
神经病学 | 671篇 |
特种医学 | 178篇 |
外科学 | 941篇 |
综合类 | 19篇 |
预防医学 | 235篇 |
眼科学 | 93篇 |
药学 | 387篇 |
中国医学 | 13篇 |
肿瘤学 | 496篇 |
出版年
2023年 | 37篇 |
2022年 | 83篇 |
2021年 | 148篇 |
2020年 | 87篇 |
2019年 | 118篇 |
2018年 | 150篇 |
2017年 | 108篇 |
2016年 | 118篇 |
2015年 | 163篇 |
2014年 | 224篇 |
2013年 | 305篇 |
2012年 | 488篇 |
2011年 | 462篇 |
2010年 | 256篇 |
2009年 | 295篇 |
2008年 | 474篇 |
2007年 | 476篇 |
2006年 | 495篇 |
2005年 | 438篇 |
2004年 | 388篇 |
2003年 | 293篇 |
2002年 | 310篇 |
2001年 | 70篇 |
2000年 | 45篇 |
1999年 | 69篇 |
1998年 | 61篇 |
1997年 | 55篇 |
1996年 | 54篇 |
1995年 | 32篇 |
1994年 | 35篇 |
1993年 | 41篇 |
1992年 | 55篇 |
1991年 | 33篇 |
1990年 | 34篇 |
1989年 | 31篇 |
1988年 | 34篇 |
1987年 | 27篇 |
1986年 | 18篇 |
1985年 | 16篇 |
1984年 | 30篇 |
1983年 | 28篇 |
1982年 | 24篇 |
1981年 | 27篇 |
1980年 | 13篇 |
1979年 | 11篇 |
1978年 | 7篇 |
1975年 | 8篇 |
1974年 | 12篇 |
1968年 | 7篇 |
1967年 | 6篇 |
排序方式: 共有6880条查询结果,搜索用时 15 毫秒
61.
Test‐retest reliability of the default mode network in a multi‐centric fMRI study of healthy elderly: Effects of data‐driven physiological noise correction techniques 下载免费PDF全文
Rocco Marchitelli Ludovico Minati Moira Marizzoni Beatriz Bosch David Bartrés‐Faz Bernhard W. Müller Jens Wiltfang Ute Fiedler Luca Roccatagliata Agnese Picco Flavio Nobili Oliver Blin Stephanie Bombois Renaud Lopes Régis Bordet Julien Sein Jean‐Philippe Ranjeva Mira Didic Hélène Gros‐Dagnac Pierre Payoux Giada Zoccatelli Franco Alessandrini Alberto Beltramello Núria Bargalló Antonio Ferretti Massimo Caulo Marco Aiello Carlo Cavaliere Andrea Soricelli Lucilla Parnetti Roberto Tarducci Piero Floridi Magda Tsolaki Manos Constantinidis Antonios Drevelegas Paolo Maria Rossini Camillo Marra Peter Schönknecht Tilman Hensch Karl‐Titus Hoffmann Joost P. Kuijer Pieter Jelle Visser Frederik Barkhof Jorge Jovicich 《Human brain mapping》2016,37(6):2114-2132
Understanding how to reduce the influence of physiological noise in resting state fMRI data is important for the interpretation of functional brain connectivity. Limited data is currently available to assess the performance of physiological noise correction techniques, in particular when evaluating longitudinal changes in the default mode network (DMN) of healthy elderly participants. In this 3T harmonized multisite fMRI study, we investigated how different retrospective physiological noise correction (rPNC) methods influence the within‐site test‐retest reliability and the across‐site reproducibility consistency of DMN‐derived measurements across 13 MRI sites. Elderly participants were scanned twice at least a week apart (five participants per site). The rPNC methods were: none (NPC), Tissue‐based regression, PESTICA and FSL‐FIX. The DMN at the single subject level was robustly identified using ICA methods in all rPNC conditions. The methods significantly affected the mean z‐scores and, albeit less markedly, the cluster‐size in the DMN; in particular, FSL‐FIX tended to increase the DMN z‐scores compared to others. Within‐site test‐retest reliability was consistent across sites, with no differences across rPNC methods. The absolute percent errors were in the range of 5–11% for DMN z‐scores and cluster‐size reliability. DMN pattern overlap was in the range 60–65%. In particular, no rPNC method showed a significant reliability improvement relative to NPC. However, FSL‐FIX and Tissue‐based physiological correction methods showed both similar and significant improvements of reproducibility consistency across the consortium (ICC = 0.67) for the DMN z‐scores relative to NPC. Overall these findings support the use of rPNC methods like tissue‐based or FSL‐FIX to characterize multisite longitudinal changes of intrinsic functional connectivity. Hum Brain Mapp 37:2114–2132, 2016. © 2016 Wiley Periodicals, Inc. 相似文献
62.
Krengli Marco Ferrara Eleonora Guaschino Riccardo Puta Erinda Turri Lucia Luciani Ilaria Sacchetti Gian Mauro Franco Pierfrancesco Brambilla Marco 《Annals of nuclear medicine》2022,36(5):450-459
Annals of Nuclear Medicine - [18F] fluorodeoxyglucose positron emission tomography/computed tomography ([18F] FDG-PET/CT) is used for diagnosis, staging, response assessment and prognosis... 相似文献
63.
Porta C Calvo E Climent MA Vaishampayan U Osanto S Ravaud A Bracarda S Hutson TE Escudier B Grünwald V Kim D Panneerselvam A Anak O Motzer RJ 《European urology》2012,61(4):826-833
Background
Elderly patients with metastatic renal cell carcinoma (mRCC) may require special treatment considerations, particularly when comorbidities are present. An understanding of the efficacy and safety of targeted agents in elderly patients with mRCC is essential to provide individualized therapy.Objective
To evaluate the efficacy and safety of everolimus in elderly patients (those ≥65 and ≥70 yr of age) enrolled in RECORD-1.Design, setting, and participants
The multicenter randomized RECORD-1 phase 3 trial (Clinicaltrials.gov identifier, NCT00410124; http://www.clinicaltrials.gov) enrolled patients with mRCC who progressed during or within 6 mo of stopping sunitinib and/or sorafenib treatment (n = 416).Intervention
Everolimus 10 mg once daily (n = 277) or placebo (n = 139) plus best supportive care. Treatment was continued until disease progression or unacceptable toxicity.Measurements
Median progression-free survival (PFS), median overall survival (OS), and time to deterioration in Karnofsky performance status (TTD-KPS) were assessed using the Kaplan-Meier method; the log-rank test was used to compare treatment arms. Other outcomes evaluated included reduction in tumor burden, overall response rate (ORR), and safety.Results and limitations
In RECORD-1, 36.8% of patients were ≥65 yr and 17.5% were ≥70 yr of age. PFS, OS, TTD-KPS, reduction in tumor burden, and ORR were similar in the elderly and the overall RECORD-1 population. Everolimus was generally well tolerated in elderly patients, and most adverse events were grade 1 or 2 in severity. The toxicity profile of everolimus was generally similar in older patients and the overall population; however, peripheral edema, cough, rash, and diarrhea were reported more frequently in the elderly regardless of treatment. The retrospective nature of the analyses was the major limitation.Conclusions
Everolimus is effective and tolerable in elderly patients with mRCC. When selecting targeted therapies in these patients, the specific toxicity profile of each agent and any patient comorbidities should be considered. 相似文献64.
Gian Piero Guerrini Alessio Vagliasindi Rosalba Lembo Luciano Solaini Paolo Soliani 《Journal of investigative surgery》2017,30(2):110-115
Introduction: The ideal surgical approach for pulmonary metastasectomy remains controversial. Thoracoscopic surgery may offer advantages in quality of life outcomes, with equivalent oncologic long-term results. This study aimed to demonstrate the validity of video-assisted thoracoscopic surgery (VATS) in the treatment of lung metastases. Methods: In all 224 patients who underwent 300 VATS metastasectomies from January 2000 to December 2013 were retrospectively reviewed. Sixty-nine patients underwent major resection (68 thoracoscopic lobectomies and one pneumonectomy) and 155 patients underwent a wedge resection/segmentectomy. Complete curative pulmonary resections were performed in 219 (97%) cases. The Kaplan–Meier method was used to estimate survival curves. Univariate and subsequent multivariate Cox model regression were performed to identify independent factors of overall survival. Results: One hundred eighty-six patients developed lung metastases from epithelial tumors, 28 from sarcomas, seven from melanomas, and three from germ cell tumors. The final pathological examination revealed no cases of R1 disease. After a mean follow-up of 40 months, 118 patients (53%) had died. According to a multivariate analysis, a better prognosis was not observed for patients with a particular histological type; in addition, disease-free interval time, age, number of metastases, and type of surgery did not have any statistical influence on long-term survival. Conclusions: Thoracoscopic surgery is a safe and efficacious procedure, with a five-year overall survival that is equivalent to open surgery. 相似文献
65.
Germ cell tumours are highly curable, especially when still at the localized stage, which is the case for most testicular tumours. Various options are available for organ-confined disease; depending on the histological review, patients with clinical stage I seminomas can be offered radiotherapy, surveillance or chemotherapy, whereas those with clinical stage I nonseminomas can be offered retroperitoneal lymph node dissection, surveillance or chemotherapy. As it is unlikely that any of these approaches will have a clear survival advantage, the most appropriate variables to be considered are acute and late side-effects, acceptability and quality of life. In recent years adjuvant chemotherapy has been extensively evaluated in patients with seminoma or nonseminoma. In this review we discuss the advantages and disadvantages of the different strategies for treating seminomas and nonseminomas, and their associated prognostic factors, and then consider future developments. 相似文献
66.
D'Amelio P Cristofaro MA Tamone C Morra E Di Bella S Isaia G Grimaldi A Gennero L Gariboldi A Ponzetto A Pescarmona GP Isaia GC 《BONE》2008,43(6):1010-1015
It has been suggested that iron-deficient rats have lower bone mass than iron-replete animals, but a clear association between bone and iron repletion has not been demonstrated in humans. A growing body of evidences also suggests a relation between lipid oxidation and bone metabolism and between iron metabolism and LDL oxidation. Iron availability to cells also depends on haptoglobin (Hp) phenotypes. Hp has also important antioxidant properties according to its phenotype, hence we evaluate whether Hp phenotype could influence bone density, iron metabolism and lipid oxidation. This cross-sectional study enrolled 455 postmenopausal women affected by osteoporosis (260) or not (195). Bone mineral density, markers of bone and iron metabolism, levels of oxidized LDL (oxLDL) and Hp phenotype were measured in all the subjects. Hp 1.1 and 2.2 frequency was higher and Hp 2.1 was lower in the patients with fragility fractures (80) compared with the controls. We therefore evaluate different Hp phenotypes as risk or protective factors against fragility fracture: Hp 2.1 is a protective factor against fracture while 1.1 is an important and 2.2 a moderate risk factor for fragility fractures. Lower serum iron was associated with elevated transferrin in patients with Hp 1.1; moreover patients had relative iron deficiency compared with the controls and fractured patients had higher level of oxLDL. We found that both iron metabolism and oxLDL varies according to Hp phenotypes and are predictive of bone density. Our data indicate that Hp 2.1 is a protective factor for fragility fractures, depending on its role on iron metabolism and its antioxidant properties. 相似文献
67.
Erre GL Marongiu A Fenu P Faedda R Masala A Sanna M Soro G Tocco A Piu D Marotto D Passiu G 《Joint, bone, spine : revue du rhumatisme》2008,75(4):426-431
ObjectiveTo assess the clinical and radiographic features of hand involvement in patients with systemic sclerosis (SSc).MethodsForty-one unselected Sardinian SSc patients (32 women, 9 men; mean age 58.9, range 31–81 years; mean disease duration 11.8 years, range 1–36 years) were evaluated in this observational cross-sectional study. Twenty-six patients had diffuse scleroderma (dSSc) and 15 limited scleroderma (lSSc). Radiological examination of the hands was performed and the films were read by two independent rheumatologists blinded to the diagnosis using a classification system of four predefined radiological patterns (normal/minimal changes, articular degenerative, articular inflammatory and periarticular pattern). Correlations between radiological pattern, clinical and serological features were assessed.ResultsThe skeletal and articular involvement of the hand was frequent in SSc, being clinically evident in 30/41 (73%) and radiologically in 33/41 (80%) of patients. The periarticular pattern (defined as the occurrence of bone resorption of ungueal tufts, soft tissue calcifications and/or flexion deformities) was the most frequent pattern detected (14/41, 34.1%) and finger flexion contractures and bone resorptions were significantly associated with interstitial lung disease, reduced FVC, oesophagus involvement and prostacycline therapy. Calcinosis (29.2%) was found to be associated with erosions, suggesting a pathogenic link. An inflammatory pattern was also radiologically frequent (8/41, 19.5%), but erosions, with the exception of those localized at distal interphalangeal joints, were demonstrated mainly in patients with clinical picture of rheumatoid arthritis overlapped with SSc. We found no significant differences in terms of radiographic findings between lSSc and dSSc with the exception of calcinosis, which was more frequent in patients with lSSc.ConclusionThis cross-sectional study confirms that the skeletal and articular involvement of the hand is frequent in SSc. 相似文献
68.
Ferrari Angela MD Lozzi Gian Piero MD Fargnoli Maria Concetta MD Peris Ketty MD 《Dermatologic surgery》2005,31(11):1448-1450
Background. A combined nevus most commonly consists of a blue nevus in combination with a Clark or Spitz nevus. Dermoscopically, combined nevus can mimic melanoma owing to the presence of dermoscopic features common to both types of lesions. Benign clinical and dermoscopic changes can occur in nevi over time, especially in children and young adults.
Objective. To describe the dermoscopic evolution of a congenital combined nevus showing unusual dermoscopic features.
Methods. Digital dermoscopic analysis was performed at the initial visit and after 8 months. The lesion was surgically excised and histopathologically examined.
Results. An asymptomatic plaque with a central blue area and peripheral brown pigmentation located on the back of a 13-year-old boy was diagnosed dermoscopically as combined nevus. Dermoscopic analysis 8 months later showed color changes from steel blue to gray-blue and black in the central area of the lesion, an increased number of blue-black dots or globules, and peripheral irregular streaks. Histopathology revealed typical features of a congenital combined nevus (blue nevus + compound nevus).
Conclusion. Over time, congenital combined nevus may show clinical and dermoscopic changes in size, color, and structure. Surgical excision is recommended when clinical and dermoscopic features are equivocal and the diagnosis of melanoma cannot be ruled out.
ANGELA FERRARI, MD, GIAN PIERO LOZZI, MD, MARIA CONCETTA FARGNOLI, MD, AND KETTY PERIS, MD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS. 相似文献
Objective. To describe the dermoscopic evolution of a congenital combined nevus showing unusual dermoscopic features.
Methods. Digital dermoscopic analysis was performed at the initial visit and after 8 months. The lesion was surgically excised and histopathologically examined.
Results. An asymptomatic plaque with a central blue area and peripheral brown pigmentation located on the back of a 13-year-old boy was diagnosed dermoscopically as combined nevus. Dermoscopic analysis 8 months later showed color changes from steel blue to gray-blue and black in the central area of the lesion, an increased number of blue-black dots or globules, and peripheral irregular streaks. Histopathology revealed typical features of a congenital combined nevus (blue nevus + compound nevus).
Conclusion. Over time, congenital combined nevus may show clinical and dermoscopic changes in size, color, and structure. Surgical excision is recommended when clinical and dermoscopic features are equivocal and the diagnosis of melanoma cannot be ruled out.
ANGELA FERRARI, MD, GIAN PIERO LOZZI, MD, MARIA CONCETTA FARGNOLI, MD, AND KETTY PERIS, MD, HAVE INDICATED NO SIGNIFICANT INTEREST WITH COMMERCIAL SUPPORTERS. 相似文献
69.
Alessandro Cucchetti MD Fabio Piscaglia MD Eugenio Caturelli MD Luisa Benvegnù MD Marco Vivarelli MD Giorgio Ercolani MD Matteo Cescon MD Matteo Ravaioli MD Gian Luca Grazi MD Luigi Bolondi MD Antonio Daniele Pinna MD 《Annals of surgical oncology》2009,16(2):413-422
The presence of cirrhosis is the only risk factor that is advocated for recurrence of hepatocellular carcinoma (HCC) 2 years
after hepatic resection compared with noncirrhotic control subjects; however, data for cohorts of exclusively patients with
cirrhosis are lacking. This study was designed to assess risk factors and annual incidence of early (<2 years) and late (>2 years)
recurrence after resection of cirrhosis and to compare these findings with those of patients with cirrhosis enrolled in HCC
surveillance programs (HCC occurrence). Data from 204 patients with cirrhosis resected for HCC and 150 surveilled for cirrhosis
were retrospectively collected and compared using propensity score matching to overcome biases of nonrandomized study. Risk
factors for early recurrence (incidence = 21.8%/year) were higher serum alpha-fetoprotein (AFP) levels, poorly differentiated
tumor, and presence of microvascular invasion (P < 0.05). Risk factors for both late recurrence (18.4%/year) and HCC occurrence (3.3%/year) were male gender, older age, and
higher serum transaminase levels; multiple primary tumors and higher AFP were additional risk factors for late recurrence
and HCC occurrence respectively (P < 0.05). After propensity adjustment, resected patients with less than two risk factors for late recurrence showed an annual
incidence of HCC (6.2%/year) similar to that of surveilled patients with ≥2 risk factors (5.8%/year; P = 0.898). Early and late recurrence of HCC for patients with cirrhosis after resection have distinct risk factors. Annual
incidence of HCC 2 years or more after resection may be similar to that of general patients because the same risk factors
are involved; assessment of these characteristics could be useful in tailoring clinical management. 相似文献
70.
Filippo Catalano Antonello Trecca Luca Rodella Francesco Lombardo Anna Tomezzoli Serena Battista Marco Silano Fabio Gaj Giovanni de Manzoni 《Surgical endoscopy》2009,23(7):1581-1586
Background Endoscopic submucosal dissection (ESD) has been developed as treatment for early gastric cancer (EGC) by Japanese authors.
However, there are no reports about its possible implementation in the Western setting. The aim of the present work is to
determine the safety and efficacy of the endoscopic treatments for EGC in an Italian cohort.
Methods Forty-five patients for a total of 48 gastric lesions were enrolled in the study. Thirty-six EMR procedures were performed
with the strip biopsy technique using a double-channel endoscope. En bloc resection refers to resection in one piece, while
piecemeal refers to resections in which the lesion was removed in multiple fragments. A total of 12 ESD were performed and
completed with IT knife. We define as curative treatment lateral and vertical margins of the resected specimens free of cancer
and repeat endoscopic finding of no recurrent disease.
Results Out of 36 EMR procedures, 10 were piecemeal resections (28%), while 26 were en bloc (72%). ESD led to en bloc resection in
11/12 cases (92%). Histological assessment of curability in the EMR group was achieved in 56% of the cases, and in 92% of
the ESD group. Mean follow-up period was 31 months (range: 12–71 months). There was no local recurrence or distant metastasis
in the curative group patients.
Conclusions These results seem to confirm the safety and the clinical efficacy of the ESD procedure in the Western world too. 相似文献