全文获取类型
收费全文 | 3039篇 |
免费 | 284篇 |
国内免费 | 22篇 |
专业分类
耳鼻咽喉 | 17篇 |
儿科学 | 120篇 |
妇产科学 | 103篇 |
基础医学 | 480篇 |
口腔科学 | 89篇 |
临床医学 | 345篇 |
内科学 | 571篇 |
皮肤病学 | 56篇 |
神经病学 | 231篇 |
特种医学 | 193篇 |
外科学 | 391篇 |
综合类 | 96篇 |
一般理论 | 4篇 |
预防医学 | 260篇 |
眼科学 | 36篇 |
药学 | 181篇 |
中国医学 | 3篇 |
肿瘤学 | 169篇 |
出版年
2022年 | 22篇 |
2021年 | 41篇 |
2020年 | 33篇 |
2019年 | 56篇 |
2018年 | 44篇 |
2017年 | 42篇 |
2016年 | 45篇 |
2015年 | 68篇 |
2014年 | 64篇 |
2013年 | 86篇 |
2012年 | 110篇 |
2011年 | 96篇 |
2010年 | 99篇 |
2009年 | 79篇 |
2008年 | 112篇 |
2007年 | 126篇 |
2006年 | 100篇 |
2005年 | 99篇 |
2004年 | 99篇 |
2003年 | 86篇 |
2002年 | 100篇 |
2001年 | 96篇 |
2000年 | 78篇 |
1999年 | 78篇 |
1998年 | 75篇 |
1997年 | 62篇 |
1996年 | 62篇 |
1995年 | 43篇 |
1994年 | 53篇 |
1993年 | 49篇 |
1992年 | 73篇 |
1991年 | 52篇 |
1990年 | 77篇 |
1989年 | 67篇 |
1988年 | 76篇 |
1987年 | 65篇 |
1986年 | 56篇 |
1985年 | 60篇 |
1984年 | 46篇 |
1983年 | 50篇 |
1982年 | 34篇 |
1981年 | 28篇 |
1980年 | 33篇 |
1979年 | 40篇 |
1978年 | 29篇 |
1977年 | 29篇 |
1976年 | 31篇 |
1972年 | 21篇 |
1970年 | 19篇 |
1969年 | 23篇 |
排序方式: 共有3345条查询结果,搜索用时 0 毫秒
91.
92.
Littera R Orrù N Caocci G Sanna M Mulargia M Piras E Vacca A Giardini C Orofino MG Visani G Bertaina A Giorgiani G Locatelli F Carcassi C La Nasa G 《British journal of haematology》2012,156(1):118-128
In a study conducted on 114 patients undergoing unrelated donor haematopoietic stem cell transplantation (HSCT) for thalassaemia, we observed that the lack of activating killer immunoglobulin-like receptors (KIRs) on donor natural killer (NK) cells significantly increased the risk of graft-versus-host disease (GvHD) [hazard risk (HR) 4.2, 95% confidence interval (CI) 1.7-10.1, P = 0.002] and transplantation-related mortality (HR 4.7, 95% CI 1.6-14.2, P = 0.01). The risk of GvHD furthermore increased when recipients heterozygous for HLA-C KIR ligand groups (C1/C2) were transplanted from donors completely lacking activating KIRs (HR 6.1, 95% CI 1.9-19.2, P = 0.002). We also found that the risk of rejection was highest when the recipient was homozygous for the C2 HLA-KIR ligand group and the donor carried two or more activating KIRs (HR 6.8, 95% CI 1.9-24.4, P = 0.005). By interpolating the number of donor activating KIRs with recipient HLA-C KIR ligands, we created an algorithm capable of stratifying patients according to the immunogenetic risk of complications following unrelated HSCT. In clinical practice, this predictive tool could serve as an important supplement to clinical judgement and decision-making. 相似文献
93.
Maria das Gra?as WS Coriolano Luciana R Belo Danielle Carneiro Amdore G Asano Paulo José AL Oliveira Douglas Monteiro da Silva Otávio G Lins 《Dysphagia》2012,27(4):550-555
Our goal was to study deglutition of Parkinson??s disease (PD) patients and normal controls (NC) using surface electromyography (sEMG). The study included 15 patients with idiopathic PD and 15 age-matched normal controls. Surface electromyography was collected over the suprahyoid muscle group. Conditions were the following: swallow at once 10 and 20?ml of water and 5 and 10?ml of yogurt of firm consistency, and freely drink 100?ml of water. During swallowing, durations of sEMG were significantly longer in PD patients than in normal controls but no significant differences of amplitudes were found. Eighty percent of the PD patients and 20?% of the NC needed more than one swallow to consume 20?ml of water, while 70?% of the PD patients and none of the NC needed more than one swallow to consume 5?ml of yogurt. PD patients took significantly more time and needed significantly more swallows to drink 100?ml of water than normal controls. We conclude that sEMG might be a simple and useful tool to study and monitor deglutition in PD patients. 相似文献
94.
95.
This pilot study compared oxygen consumption during arm crank and cycle ergometer tests in 15 women. The mean (SD) peak oxygen consumption was less with arm cranking (25 (5) ml.kg?1.min?1) than with cycling (40 (7) ml.kg?1.min?1), p < 0.0001. The mean (SD) anaerobic threshold was less with arm cranking (13 (2) ml.kg?1.min?1) than with cycling (20 (4) ml.kg?1.min?1), p < 0.0001. There was moderate correlation, r2 = 0.60, between the anaerobic thresholds determined by arm and leg exercise, p = 0.0007. This study suggests that arm crank cardiopulmonary exercise testing could be used for pre‐operative assessment in those unable to cycle. 相似文献
96.
GEMMA PELARGONIO MARIA L. NARDUCCI ELEONORA RUSSO MICHELA CASELLA PASQUALE SANTANGELI ROBERT CANBY AMIN AL‐AHMAD LARRY D. PRICE LUIGI DI BIASE CANDICE J. KWARK MARK HARWOOD FRANCESCO PERNA GIANLUIGI BENCARDINO CAROLINA IERARDI ENRICO M. TRECARICHI ENRICA SANTELLI MARIO TUMBARELLO PRASANT MOHANTY SHANE BAILEY JOHN DAVID BURKHARDT FULVIO BELLOCCI ANDREA NATALE ANTONIO DELLO RUSSO 《Journal of cardiovascular electrophysiology》2012,23(10):1103-1108
Transvenous Lead Extraction . Introduction: As the population ages, the number of elderly patients with implantable cardiac devices referred for transvenous lead extraction will dramatically increase in Western countries. The safety and effectiveness of lead extraction in elderly patients has not been well evaluated. We report the safety and effectiveness of transvenous lead extraction in octogenarians. Methods and Results: From January 2005 to January 2011, we reviewed data from consecutive patients ≥ 80 years referred to our institutions for transvenous lead extraction because of cardiac device infection or lead malfunction. Clinical characteristics, procedural features, and periprocedural major and minor complications were compared between octogenarians and younger patients. Out of 849 patients undergoing lead extraction in the participating institutions during the study period, 150 (18%) patients were octogenarians (mean age 84 years; range 80–96; 64% males). A significantly higher percentage of octogenarians presented with chronic renal failure (55% vs 26%; P < 0.001), history of malignancy (22% vs 6%; P < 0.001), and chronic obstructive pulmonary disease (46% vs 19%; P < 0.001). Complete lead extraction rates were similar in the 2 age groups (97% in octogenarians vs 96% in patients <80 years; P = 0.39). Periprocedural death occurred in 2 (1.3%) patients ≥80 years and in 5 (0.72%) patients <80 years (P = 0.45 for comparison). No differences in terms of other periprocedural major and minor complications were found between the 2 age groups. Conclusion: Despite presenting with a significantly higher rate of comorbidities, transvenous lead extraction can be performed safely and successfully in octogenarians. (J Cardiovasc Electrophysiol, Vol. 23 pp. 1103‐1108, October 2012) 相似文献
97.
98.
Anat Mirelman PhD Talia Heman MsPT Kira Yasinovsky BS Avner Thaler MD Tanya Gurevich MD Karen Marder MD Susan Bressman MD Anat Bar‐Shira PhD Avi Orr‐Urtreger MD PhD Nir Giladi MD Jeffrey M. Hausdorff PhD 《Movement disorders》2013,28(12):1683-1690
Patients with Parkinson's disease (PD) who carry the G2019S mutation (a glycine to serine substitution at amino acid 2019) in the leucine‐rich repeat kinase 2 (LRRK2) gene are generally believed to be clinically indistinguishable from patients with sporadic PD. There are, however, conflicting reports on the relationship between the mutation and the motor phenotype. We quantitatively compared gait and mobility in patients with PD carriers of the G2019S mutation to non‐carrier patients with PD to better understand the genotype‐phenotype relationship. Fifty patients with PD carriers of the G2019S LRRK2 mutation and 50 age, disease duration, and disease severity matched PD non‐carriers were studied. An accelerometer quantified gait under three walking conditions: usual‐walking, dual‐tasking, and fast‐walking. The Unified Parkinson's Disease Rating Scale classified patients into PD sub‐types and the Timed Up and Go quantified mobility and fall risk. In all three walking conditions, gait variability was larger and the walking pattern was less consistent among the PD mutation carriers (P < 0.016). The PD carriers also took longer to complete the Timed Up and Go (P = 0.011) and were more likely to report having fallen in the previous year (P = 0.018). 64% of the PD carriers were classified as belonging to the postural‐instability‐gait‐difficulty (PIGD) sub‐type compared to only 17% of the PD non‐carriers (P < 0.0001). Among patients with PD, the G2019S mutation in the LRRK2 gene is apparently associated with increased gait variability, an increased fall risk, and the PIGD sub‐type. Therapeutic approach specifically designed to delay gait disturbances and falls may be justified in patients who carry the G2019S mutation. © 2013 International Parkinson and Movement Disorder Society 相似文献
99.
Sage Hahn Scott Mackey Janna Cousijn John J. Foxe Andreas Heinz Robert Hester Kent Hutchinson Falk Kiefer Ozlem Korucuoglu Tristram Lett Chiang-Shan R. Li Edythe London Valentina Lorenzetti Luijten Maartje Reza Momenan Catherine Orr Martin Paulus Lianne Schmaal Rajita Sinha Zsuzsika Sjoerds Dan J. Stein Elliot Stein Ruth J. van Holst Dick Veltman Henrik Walter Reinout W. Wiers Murat Yucel Paul M. Thompson Patricia Conrod Nicholas Allgaier Hugh Garavan 《Human brain mapping》2022,43(1):555-565
To identify neuroimaging biomarkers of alcohol dependence (AD) from structural magnetic resonance imaging, it may be useful to develop classification models that are explicitly generalizable to unseen sites and populations. This problem was explored in a mega-analysis of previously published datasets from 2,034 AD and comparison participants spanning 27 sites curated by the ENIGMA Addiction Working Group. Data were grouped into a training set used for internal validation including 1,652 participants (692 AD, 24 sites), and a test set used for external validation with 382 participants (146 AD, 3 sites). An exploratory data analysis was first conducted, followed by an evolutionary search based feature selection to site generalizable and high performing subsets of brain measurements. Exploratory data analysis revealed that inclusion of case- and control-only sites led to the inadvertent learning of site-effects. Cross validation methods that do not properly account for site can drastically overestimate results. Evolutionary-based feature selection leveraging leave-one-site-out cross-validation, to combat unintentional learning, identified cortical thickness in the left superior frontal gyrus and right lateral orbitofrontal cortex, cortical surface area in the right transverse temporal gyrus, and left putamen volume as final features. Ridge regression restricted to these features yielded a test-set area under the receiver operating characteristic curve of 0.768. These findings evaluate strategies for handling multi-site data with varied underlying class distributions and identify potential biomarkers for individuals with current AD. 相似文献
100.
The circadian oscillators of genetically short-period and long-period Drosophila exhibit reciprocal behaviour in four distinct ways: (1) with respect to the dependence of period on temperature, (2) in the change of period during constant darkness after ten days of constant light, (3) in the change of period during the second ten days of darkness as compared with the period during the first ten days, and (4) in the period change resulting from exposure to low-intensity constant light. The homeostatic control of the dependence of period length on temperature is impaired in the mutants as compared with wild-type files. The normal Drosophila pacemaker may comprise two mutually coupled oscillators, whereas the mutants may represent a reduction in activity of one or the other constituent oscillator. 相似文献