全文获取类型
收费全文 | 3839篇 |
免费 | 198篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 42篇 |
儿科学 | 87篇 |
妇产科学 | 73篇 |
基础医学 | 371篇 |
口腔科学 | 115篇 |
临床医学 | 291篇 |
内科学 | 940篇 |
皮肤病学 | 51篇 |
神经病学 | 439篇 |
特种医学 | 157篇 |
外科学 | 894篇 |
综合类 | 3篇 |
预防医学 | 106篇 |
眼科学 | 105篇 |
药学 | 147篇 |
中国医学 | 2篇 |
肿瘤学 | 267篇 |
出版年
2024年 | 5篇 |
2023年 | 36篇 |
2022年 | 93篇 |
2021年 | 197篇 |
2020年 | 107篇 |
2019年 | 122篇 |
2018年 | 150篇 |
2017年 | 99篇 |
2016年 | 129篇 |
2015年 | 145篇 |
2014年 | 186篇 |
2013年 | 248篇 |
2012年 | 309篇 |
2011年 | 316篇 |
2010年 | 186篇 |
2009年 | 176篇 |
2008年 | 202篇 |
2007年 | 214篇 |
2006年 | 198篇 |
2005年 | 157篇 |
2004年 | 169篇 |
2003年 | 139篇 |
2002年 | 151篇 |
2001年 | 37篇 |
2000年 | 22篇 |
1999年 | 27篇 |
1998年 | 24篇 |
1997年 | 20篇 |
1996年 | 10篇 |
1995年 | 14篇 |
1994年 | 9篇 |
1993年 | 13篇 |
1992年 | 13篇 |
1991年 | 14篇 |
1990年 | 17篇 |
1989年 | 8篇 |
1988年 | 10篇 |
1987年 | 9篇 |
1986年 | 8篇 |
1985年 | 16篇 |
1984年 | 8篇 |
1983年 | 7篇 |
1982年 | 8篇 |
1981年 | 8篇 |
1978年 | 4篇 |
1971年 | 4篇 |
1970年 | 3篇 |
1969年 | 9篇 |
1968年 | 5篇 |
1966年 | 5篇 |
排序方式: 共有4090条查询结果,搜索用时 46 毫秒
31.
32.
Jonathan T. Sims Venkatesh Krishnan Ching-Yun Chang Sarah M. Engle Giacomo Casalini George H. Rodgers Nicoletta Bivi Brian J. Nickoloff Robert J. Konrad Stephanie de Bono Richard E. Higgs Robert J. Benschop Silvia Ottaviani Anabela Cardoso Ajay Nirula Mario Corbellino Justin Stebbing 《The Journal of allergy and clinical immunology》2021,147(1):107-111
33.
Martina Meoli Franco Muggli Sebastiano A.G. Lava Mario G. Bianchetti Carlo Agostoni Claudine Kocher Thomas W. Bührer Letizia Ciliberti Giacomo D. Simonetti Gregorio P. Milani 《Nutrients》2021,13(5)
Vitamin D has been claimed to be effective in the response to infections, including the respiratory syndrome coronavirus 2 (SARS-CoV-2). It is supposed that lockdown measures and fear of SARS-CoV-2 infection might reduce vitamin D levels through the modification of lifestyle. However, very few data exist on the association between lockdown measures and vitamin D status in humans. For this cross-sectional comparative study, adolescents (n = 298) aged 18 to 19 years were enrolled during the compulsory military fitness-for-duty evaluation between July and December 2020 in Southern Switzerland. Beyond anthropometric measurements, participants filled in a structured questionnaire about their lifestyle and a blood specimen was sampled for the determination of total 25-hydroxy-vitamin D. The obtained data were compared with those of 437 adolescents enrolled at the military fitness-for-duty evaluation during the same period of the year in the context of the CENERI study (2014–2016). The anthropometric measures were similar between the two study groups. The levels of vitamin D were also comparable (77 (64–91) vs. 74 (60–92) nmol/L, p = 0.50; median and interquartile range). A total of 38 (13%) and 43 (9.8%) subjects presented insufficient (<50 nmol/L) levels of vitamin D (p = 0.42) during the current pandemic and in the CENERI study, respectively. These data do not support the hypothesis that during the SARS-CoV-2 pandemic, late adolescents are at higher risk of vitamin insufficiency. 相似文献
34.
35.
36.
Antonio Loforte Mariafrancesca Fiorentino Giacomo Murana Gregorio Gliozzi Giulio Giovanni Cavalli Carlo Mariani Sofia Martin Suarez Davide Pacini 《Transplantation proceedings》2021,53(1):311-317
BackgroundThe occurrence of early graft failure (EGF) after heart transplantation (Htx) often requires a mechanical circulatory support (MCS) therapy. The aims of our study were to identify risk factors of mechanically supported severe EGF and evaluate their impact on both early and late outcomes.MethodsBetween January 2000 and December 2019, 499 consecutive adult patients underwent Htx at our institution. Severe EGF was defined as the need for extracorporeal life support (ECLS) within 24 hours after surgery. All available recipient and donor variables were retrospectively analyzed.ResultsOverall, EGF occurred in 58 (11.6%) patients. Post-Htx peripheral or central ECLS was necessary in 32 (6.4%) cases. Independent predictors of severe EGF were, in the recipient group, preoperative transpulmonary gradient (TPG) >12 mm Hg (odds ratio [OR] 4.1, P = .013), preoperative inotropic score >10 (OR 7.3, P = .0001), and pre-Htx ECLS support (OR 5.2, P = .015), while in the donors, a Eurotransplant donor score ≥17 (OR 8.5, P = .005). The absence of EGF was related with a better survival at 1 year and 5 years (94% and 85%, respectively) compared with EGF requiring ECLS population (36% and 28% at 1 year and 5 years, respectively; P < .001). A five-year conditional survival rate did not differ significantly (85% no EGF vs 83% EGF requiring ECLS).ConclusionBoth donor and recipient factors may influence EGF occurrence. Post-Htx ECLS may impact negatively early; however, patients weaned from ECLS eventually benefit from such a rescue treatment with outcomes comparable with Htx patients who did not suffer EGF. 相似文献
37.
Vittorio Scaravilli Silvia Scansani Alice Grasso Amedeo Guzzardella Marco Vicenzi Irene Rota Mario Nosotti Alberto Zanella Francesco Blasi Antonio Pesenti Giacomo Grasselli 《Transplantation proceedings》2021,53(1):260-264
Knowledge of preoperative right heart function of adult patients with cystic fibrosis (CF) awaiting lung transplant (LUTX) is limited. The echocardiography of adult patients with CF enlisted for LUTX was retrospectively analyzed and compared with standards and invasive analyses (right heart catheterization, multigated radionuclide ventriculography). We included 49 patients (reported as mean ± standard deviation; 29 ± 9 years of age; forced expiratory volume in first second of expiration, 31% ± 11% predicted; lung allocation score, 36 ± 5; invasive mean pulmonary artery pressure, 17 ± 5 mm Hg; multigated radionuclide ventriculography right ventricle [RV] ejection fraction, 50% ± 9%). Patients had increased RV end-diastolic area, RV wall thickness, and increased pulmonary artery acceleration time with subnormal tricuspid annular plane systolic excursion, tissue Doppler positive peak systolic velocity, and fraction area change. Subnormal tricuspid annular plane systolic excursion (< 23 mm), tissue Doppler positive peak systolic velocity (< 14 cm/s), and fraction area change (< 49%) had high sensitivity and negative predictive value in predicting impaired RV.ejection fractionA good correlation between echocardiographic estimated and invasively measured systolic pulmonary artery pressure was observed (R2 = 0.554, P < .001). Adults with CF awaiting LUTX have morphologic alterations of the right heart, with subclinical impairment of RV systolic function. Echocardiography may be used as a bedside, repeatable, and reliable noninvasive test to screen further deterioration in RV function while on the waiting list for LUTX. More prospective follow-up echocardiographic studies are necessary to confirm such a hypothesis. 相似文献
38.
Riccardo Schiavina Matteo Droghetti Giacomo Novara Lorenzo Bianchi Caterina Gaudiano Valeria Panebianco Marco Borghesi Pietro Piazza Federico Mineo Bianchi Marco Guerra Beniamino Corcioni Michelangelo Fiorentino Francesca Giunchi Paolo Verze Cristian Pultrone Rita Golfieri Angelo Porreca Vincenzo Mirone Eugenio Brunocilla 《Urologic oncology》2021,39(7):433.e1-433.e7
BackgroundWe aim to evaluate the impact of multiparametric magnetic resonance imaging and fusion-target biopsy for early reclassification of patients with low-risk Prostate Cancer in a randomized trial.Materials and methodsBetween 2015 and 2018, patients diagnosed with Prostate Cancer after random biopsy fulfilling PRIAS criteria were enrolled and centrally randomized (1:1 ratio) to study group or control group. Patients randomized to study group underwent multiparametric magnetic resonance imaging at 3 months from enrollment: patients with positive findings (PIRADS-v2>2) underwent fusion-target biopsy; patients with negative multiparametric magnetic resonance imaging or confirmed ISUP - Grade Group 1 at fusion-target biopsy were managed according to PRIAS schedule and 12-core random biopsy was performed at 12 months. Patients in control group underwent PRIAS protocol, including a confirmatory 12-core random biopsy at 12 months. Primary endpoint was a reduction of reclassification rate at 12-month random biopsy in study group at least 20% less than controls. Reclassification was defined as biopsy ISUP Grade Group 1 in >2 biopsy cores or disease upgrading.ResultsA total of 124 patients were randomized to study group (n = 62) or control group (n = 62). Around 21 of 62 patients (34%) in study group had a positive multiparametric magnetic resonance imaging, and underwent fusion-target biopsy, with 11 (17.7%) reclassifications. Considering the intention-to-treat population, reclassification rate at 12-month random biopsy was 6.5% for study group and 29% for control group, respectively (P < 0.001).ConclusionsThe early employment of multiparametric magnetic resonance imaging for active surveillance patients enrolled after random biopsy consents to significantly reduce reclassifications at 12-month random biopsy. 相似文献
39.
40.
F Venuta E A Rendina M Bufi G Della Rocca T De Giacomo M G Costa F Pugliese C Coccia A M Ciccone G F Coloni 《The Journal of thoracic and cardiovascular surgery》1999,118(1):107-114
OBJECTIVE: Retrograde pneumoplegia seems to improve early graft function in experimental and clinical lung transplantation. We evaluated the role of retrograde flushing in addition to antegrade pneumoplegia in clinical lung transplantation. METHODS: Fourteen patients undergoing lung transplantation were randomized into 2 groups: in group I we performed antegrade pulmonary artery flushing with alprostadil (prostaglandin E1) and modified Euro-Collins solution at the time of retrieval. In group II additional retrograde flushing through the pulmonary veins was performed at the back table, before reimplantation. Hemodynamic variables, mean airway pressure, and blood gas analysis were monitored at different time points. Postoperative volumetric monitoring was performed to assess extravascular lung water. The reimplantation response was assessed by a radiographic score; extubation time and intensive care unit stay were recorded. RESULTS: During retrograde flushing, blood and clots coming out from the pulmonary artery were observed; 2 lungs harvested from a donor with multiple bone fractures had fat emboli in the retrograde perfusate. Hemodynamic monitoring did not demonstrate any difference between the 2 groups. The ratio of arterial oxygen tension to inspired oxygen fraction, extravascular lung water, duration of intubation, and length of stay in the intensive care unit were improved in group II, but the differences did not reach statistical significance. Intrapulmonary shunt fraction was significantly improved in group II at each time point ( P =.02), as well as indexed alveolar-arterial oxygen tension gradient (P =.04), mean airway pressure (P =.04), and chest x-ray score ( P =.03). CONCLUSIONS: Preimplantation retrograde flushing is not detrimental and helps to improve early graft function. 相似文献