全文获取类型
收费全文 | 3181篇 |
免费 | 207篇 |
国内免费 | 11篇 |
专业分类
耳鼻咽喉 | 36篇 |
儿科学 | 58篇 |
妇产科学 | 100篇 |
基础医学 | 495篇 |
口腔科学 | 333篇 |
临床医学 | 235篇 |
内科学 | 644篇 |
皮肤病学 | 62篇 |
神经病学 | 206篇 |
特种医学 | 82篇 |
外科学 | 408篇 |
综合类 | 14篇 |
一般理论 | 3篇 |
预防医学 | 271篇 |
眼科学 | 74篇 |
药学 | 246篇 |
中国医学 | 19篇 |
肿瘤学 | 113篇 |
出版年
2023年 | 33篇 |
2022年 | 99篇 |
2021年 | 135篇 |
2020年 | 88篇 |
2019年 | 136篇 |
2018年 | 111篇 |
2017年 | 83篇 |
2016年 | 84篇 |
2015年 | 99篇 |
2014年 | 131篇 |
2013年 | 171篇 |
2012年 | 240篇 |
2011年 | 274篇 |
2010年 | 125篇 |
2009年 | 107篇 |
2008年 | 186篇 |
2007年 | 170篇 |
2006年 | 137篇 |
2005年 | 133篇 |
2004年 | 112篇 |
2003年 | 114篇 |
2002年 | 67篇 |
2001年 | 48篇 |
2000年 | 66篇 |
1999年 | 62篇 |
1998年 | 22篇 |
1997年 | 14篇 |
1996年 | 12篇 |
1995年 | 15篇 |
1994年 | 15篇 |
1993年 | 9篇 |
1992年 | 30篇 |
1991年 | 31篇 |
1990年 | 30篇 |
1989年 | 16篇 |
1988年 | 26篇 |
1987年 | 16篇 |
1986年 | 16篇 |
1985年 | 15篇 |
1984年 | 15篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1979年 | 14篇 |
1978年 | 5篇 |
1977年 | 7篇 |
1973年 | 9篇 |
1972年 | 6篇 |
1969年 | 6篇 |
1968年 | 5篇 |
1967年 | 4篇 |
排序方式: 共有3399条查询结果,搜索用时 15 毫秒
1.
2.
A. Montalto V. Piazza F. Albi R. Gherli C. Contento A. Palermo F. Musumeci 《Transplantation proceedings》2019,51(1):206-209
Background
Pump speed optimization in patients implanted with a ventricular assist device represents a major challenge during the follow-up period. We present our findings on whether combined invasive hemodynamic ramp tests and cardiopulmonary exercise testing (CPX) can help optimize patient management.Methods
Eighteen patients implanted with a HeartMate 3 (HM3) device underwent ramp tests with right heart catheterization (including central venous pressure [CVP], pulmonary artery pressure, pulmonary capillary wedge pressure [PCWP], and blood pressure) and echocardiography. Data were recorded at up to 4 speed settings. Speed changes were in steps of 200 revolutions/min (rpm). Evaluation of functional capacity by CPX was conducted according to the modified Bruce protocol.Results
Only 30% of patients had normal PCWPs at their original rpm settings. In going from lowest to highest speeds, cardiac output improved by 0.25 ± 0.35 L/min/step (total change, 1.28 ± 0.3 L/min), and PCWP decreased by 1.9 ± 0.73 mm Hg/step (total change, 6 ± 1.6 mm Hg). CVP and systolic blood pressure did not change significantly with rpm. The rpm assessment was adjusted based on test results to achieve CVPs and PCWPs as close to normal limits as possible, which was feasible in all patients. On CPX, all patients demonstrated good performance (peak VO2, 16.8 ± 3.5 mL/kg/min).Conclusion
Hemodynamic ramp testing provides an objective means of optimizing rpm, and has the potential to provide good exercise tolerance. 相似文献3.
4.
John Lennon Silva Cunha Amanda Almeida Leite Thamiris de Castro Abrantes Lorena Passoni Vervloet Thayn Melo de Lima Morais Gerson de Oliveira Paiva Neto Tatiana Nayara Librio Kimura Snia Maria Soares Ferreira Ricardo Luiz Cavalcanti de Albuquerque‐Júnior Aline Corrêa Abraho Mario Jos Romaach Bruno Augusto Benevenuto de Andrade Oslei Paes de Almeida Ciro Dantas Soares 《Journal of cutaneous pathology》2021,48(1):24-33
5.
Effect of nedocromil on bronchospasm induced by inhalation of substance P in asthmatic subjects 总被引:3,自引:0,他引:3
N Crimi F Palermo R Oliveri B Palermo C Vancheri R Polosa A Mistretta 《Clinical allergy》1988,18(4):375-382
Several studies have demonstrated that neuropeptides are present in peptidergic fibres of bronchial tissue. The aim of the present study was to evaluate in vivo the effect of nedocromil sodium (2 x 2 mg) on bronchospasm induced by inhalation of substance P. Six moderate asthmatic patients, mean age 25.17 years, were studied. Airway response was measured as FEV1 and the dose of substance P (using a dose range of 23-736 nmol) producing a 20% decrease in FEV1 (PD20) was calculated from the individual semilogarithmic dose-response curves. Patients were studied on 3 separate days in a randomized, double-blind manner. On the first day a baseline PD20 value was determined. On subsequent days substance P challenge was performed after pretreatment (20 min before challenge) with either placebo or nedocromil sodium. Student's paired t-test and Wilcoxon's test were used for statistical analysis. The results of this study demonstrated that inhalation of substance P causes a dose-dependent bronchoconstriction and that the bronchoconstriction induced by substance P can be prevented by pre-treatment with nedocromil sodium. 相似文献
6.
Marina H C G Magalh?es Cristiane Barbosa da Silveira Carla Ruffeil Moreira Marcelo Gusm?o Paraíso Cavalcanti 《Oral surgery, oral medicine, oral pathology, oral radiology, and endodontics》2007,103(6):836-842
Mandibulofacial dysostosis (Treacher Collins Syndrome) is an autosomal dominant genetic disorder that probably derives from inhibition of the facial structures from the first and second branchial arches. The facial pattern of the syndrome is a convex facial profile with a prominent nose above a retruded chin. The eyes are deformed by antimongoloid slant of the palpebral fissures and facial bones are hypoplastic. The alterations are caused by mutation in gene 5q32-33.1, which encodes the nucleolar phosphoprotein treacle. Computed tomography images are able to demonstrate craniofacial bones, allowing the morphological analysis of these bones in individuals with complex deformities. The purpose of this paper is to present the results of a clinical and computed tomography investigation of two patients with Treacher Collins syndrome. 相似文献
7.
Thiago Silva Torres Valeria Cavalcanti Rolla 《The international journal of tuberculosis and lung disease》2006,10(11):1302; author reply 1302-1302; author reply 1303
8.
Ana C Mendes M Madalena Caldeira Claudia Silva Shawn C Burgess Matthew E Merritt Filipe Gomes Cristina Barosa Teresa C Delgado Fatima Franco Pedro Monteiro Luis Providencia John G Jones 《Magnetic resonance in medicine》2006,56(5):1121-1125
Menthol glucuronide was isolated from the urine of a healthy 70-kg female subject following ingestion of 400 mg of peppermint oil and 6 g of 99% [U-(13)C]glucose. Glucuronide (13)C-excess enrichment levels were 4-6% and thus provided high signal-to-noise ratios (SNRs) for confident assignment of (13)C-(13)C spin-coupled multiplet components within each (13)C resonance by (13)C NMR. The [U-(13)C]glucuronide isotopomer derived via direct pathway conversion of [U-(13)C]glucose to [U-(13)C]UDP-glucose was resolved from [1,2,3-(13)C(3)]- and [1,2-(13)C(2)]glucuronide isotopomers derived via Cori cycle or indirect pathway metabolism of [U-(13)C]glucose. In a second study, a group of four overnight-fasted patients (63 +/- 10 kg) with severe heart failure were given peppermint oil and infused with [U-(13)C]glucose for 4 hr (14 mg/kg prime, 0.12 mg/kg/min constant infusion) resulting in a steady-state plasma [U-(13)C]glucose enrichment of 4.6% +/- 0.6%. Menthol glucuronide was harvested and glucuronide (13)C-isotopomers were analyzed by (13)C NMR. [U-(13)C]glucuronide enrichment was 0.6% +/- 0.1%, and the sum of [1,2,3-(13)C(3)] and [1,2-(13)C(2)]glucuronide enrichments was 0.9% +/- 0.2%. From these data, flux of plasma glucose to hepatic UDPG was estimated to be 15% +/- 4% that of endogenous glucose production (EGP), and the Cori cycle accounted for at least 32% +/- 10% of GP. 相似文献
9.
Nuno Fonseca Filomena Caetano José Santos Filipe Seixo Leonel Bernardino Isabel Silvestre Paula Cardoso Filomena Segurado Lopes Inês 《Revista portuguesa de cardiologia》2004,23(3):365-375
INTRODUCTION: In patients (pts) with atrial fibrillation (AF) of more than 48 hours' duration, electrical cardioversion (ECV) should only be performed after 3 weeks of effective anticoagulation. Transesophageal echocardiography (TEE) allows earlier ECV; however, despite exclusion of thrombi in the atrium and left atrial appendage (LAA), cases of thromboembolism related to ECV have been documented in AF. To define a low-risk group for cardioversion without previous anticoagulation, pts were selected for immediate ECV if no thrombi or dynamic spontaneous echo contrast (auto-contrast) were found after TEE and if LAA velocity was more than 0.25 m/sec. METHODS AND RESULTS: We performed TEE in 31 consecutive pts referred for ECV for AF of more than 48 hours' duration and without previous anticoagulation. After TEE the pts eligible for immediate ECV began anticoagulation with low molecular weight heparin (enoxaparin), subcutaneously in therapeutic doses, together with warfarin immediately before cardioversion. Enoxaparin was continued until an INR of over 2 was reached. Based on the TEE findings, the pts were divided in 2 groups: immediate ECV, group A, 20 pts with a mean age of 62 +/- 13 years, 6 female; and conventional therapy with warfarin before ECV, group B, 11 pts, mean age of 67 +/- 10 years (p < 0.05), 2 female. None of the pts in either group had mitral stenosis or previous episodes of thromboembolism. The mean transverse diameter of the left atrium in the 31 pts was 47 +/- 4.5 mm, without statistically significant differences between the 2 groups. Of the 11 pts in group B, 3 had a thrombus in the LAA, 6 dynamic spontaneous echo contrast and the remainder LAA velocities of less than 0.25 m/sec. ECV was achieved in all the pts, with no complications. Oral anticoagulation was maintained for at least a month. At one month, sinus rhythm was maintained in 75% of group A and 45% of group B (p < 0.01). CONCLUSION: In pts with AF of more than 48 hours' duration and no previous history of thromboembolism, the use of our exclusion criteria during TEE enabled stratification of a low-risk population for immediate ECV, which was accomplished effectively and safely in 2/3 of the pts. This strategy is associated with early symptomatic improvement, and may contribute to maintenance of sinus rhythm after one month, which was significantly better than in the pts who had prolonged therapy with warfarin before ECV, despite the differences found in age and left ventricular function. 相似文献