全文获取类型
收费全文 | 22997篇 |
免费 | 1201篇 |
国内免费 | 254篇 |
专业分类
耳鼻咽喉 | 252篇 |
儿科学 | 479篇 |
妇产科学 | 672篇 |
基础医学 | 2625篇 |
口腔科学 | 524篇 |
临床医学 | 1696篇 |
内科学 | 6192篇 |
皮肤病学 | 398篇 |
神经病学 | 2475篇 |
特种医学 | 889篇 |
外科学 | 3664篇 |
综合类 | 46篇 |
一般理论 | 4篇 |
预防医学 | 917篇 |
眼科学 | 281篇 |
药学 | 1354篇 |
中国医学 | 48篇 |
肿瘤学 | 1936篇 |
出版年
2024年 | 23篇 |
2023年 | 187篇 |
2022年 | 402篇 |
2021年 | 717篇 |
2020年 | 446篇 |
2019年 | 525篇 |
2018年 | 688篇 |
2017年 | 559篇 |
2016年 | 643篇 |
2015年 | 714篇 |
2014年 | 930篇 |
2013年 | 1121篇 |
2012年 | 1770篇 |
2011年 | 1793篇 |
2010年 | 1015篇 |
2009年 | 996篇 |
2008年 | 1621篇 |
2007年 | 1602篇 |
2006年 | 1457篇 |
2005年 | 1397篇 |
2004年 | 1359篇 |
2003年 | 1217篇 |
2002年 | 1078篇 |
2001年 | 153篇 |
2000年 | 123篇 |
1999年 | 169篇 |
1998年 | 187篇 |
1997年 | 167篇 |
1996年 | 168篇 |
1995年 | 126篇 |
1994年 | 86篇 |
1993年 | 95篇 |
1992年 | 91篇 |
1991年 | 68篇 |
1990年 | 64篇 |
1989年 | 78篇 |
1988年 | 51篇 |
1987年 | 64篇 |
1986年 | 52篇 |
1985年 | 38篇 |
1984年 | 55篇 |
1983年 | 48篇 |
1982年 | 35篇 |
1981年 | 41篇 |
1980年 | 42篇 |
1979年 | 19篇 |
1978年 | 14篇 |
1977年 | 20篇 |
1976年 | 15篇 |
1974年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
Paolo Martinelli Giovanni Rizzo David Manners Caterina Tonon Fabio Pizza Claudia Testa Cesa Scaglione Bruno Barbiroli Raffaele Lodi 《Movement disorders》2007,22(8):1182-1185
The pathophysiology of essential tremor (ET) is unknown. PET and fMRI studies have revealed bilateral activation and (1)H-MRS studies metabolic abnormalities in the cerebellum and other functionally related brain structures in ET. Diffusion-weighted imaging (DWI) was used to search for evidence of tissue integrity abnormalities in these areas in ET patients and 10 matched controls by calculating water apparent diffusion coefficients (ADCs). Regions of interest included the left and right cerebellum, red nucleus, thalamus, caudate, putamen, pallidum, and frontal white matter. Histograms of ADCs were generated for all pixels in the infratentorial compartment and manually segmented areas corresponding to brainstem, vermis, and cerebellar hemispheres. ADC values were similar in all brain areas in patients and controls. Our study did not detect changes affecting the investigated brain regions in ET patients. These findings argue against major structural damage in the ET brain, although more subtle neurodegenerative changes cannot be ruled out. 相似文献
33.
Salvatore Serra Giuliana Brunetti Giovanni Vacca Carla Lobina Mauro A M Carai Gian Luigi Gessa Giancarlo Colombo 《Alcohol》2003,29(2):101-108
Results of a recent study have demonstrated that exposure to multiple ethanol concentrations and repeated ethanol deprivation periods in Indiana ethanol-preferring (P) rats resulted in the development of an alcohol deprivation effect (ADE; the temporary increase in voluntary ethanol intake after a period of deprivation from ethanol) characterized by consumption of intoxicating amounts of ethanol. The current study was designed to possibly extend these results to Sardinian alcohol-preferring (sP) rats, generated with the same selective program previously used for P rats. To this aim, ethanol-naive sP rats were exposed initially to the home cage four-bottle choice [10%, 20%, and 30% (vol./vol.) ethanol solutions and water] for eight consecutive weeks. Subsequently, rats were divided into two groups: The first group had continuous access to the four-bottle regimen (nondeprived rats), and the second group was exposed to five cycles of 14-day periods of deprivation from ethanol and 14-day periods of reexposure to the four-bottle regimen. An ADE developed after each deprivation period. However, the extra intake of ethanol was limited to the first hour of each reaccess period. Magnitude of ADE did not change with repeated periods of deprivation. However, a shift in preference toward the two highest concentrations of ethanol solutions was evident from the first reexposure to ethanol and was maintained throughout the study. These results provide further evidence on the heterogeneity of ethanol-drinking behavior among rat lines selectively bred for high ethanol preference and consumption. 相似文献
34.
Marco Cirillo Andrea Amaducci Emmanuel Villa Margherita Dalla Tomba Federico Brunelli Zen Mhagna Giovanni Troise Eugenio Quaini 《Journal of cardiothoracic surgery》2006,1(1):40-11
Background
Long-term morphofunctional outcome may vary widely in surgical anterior left ventricular wall restoration, suggesting variability in post-surgical remodeling similar to that observed following acute myocardial infarction. The aim of this pilot study was to demonstrate that surgical restoration obtained with a particular shape of endoventricular patch leads to steady morphofunctional ventricular improvement when geometry, volume and residual akinesia can be restored as normal as possible. 相似文献35.
36.
Claudio Babiloni Giuliano Binetti Emanuele Cassetta Gloria Dal Forno Claudio Del Percio Florinda Ferreri Raffaele Ferri Giovanni Frisoni Koichi Hirata Bartolo Lanuzza Carlo Miniussi Davide V Moretti Flavio Nobili Guido Rodriguez Gian Luca Romani Serenella Salinari Paolo M Rossini 《Clinical neurophysiology》2006,117(2):252-268
OBJECTIVE: The present study tested the hypothesis that cortical electroencephalographic (EEG) rhythms. change across normal elderly (Nold), mild cognitive impairment (MCI), and Alzheimer's disease (AD) subjects as a function of the global cognitive level. METHODS: Resting eyes-closed EEG data were recorded in 155 MCI, 193 mild AD, and 126 age-matched Nold subjects. EEG rhythms of interest were delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-10.5 Hz), alpha 2 (10.5-13 Hz), beta 1 (13-20 Hz), and beta 2 (20-30 Hz). EEG cortical sources were estimated by LORETA. RESULTS: Occipital delta and alpha 1 sources in parietal, occipital, temporal, and 'limbic' areas had an intermediate magnitude in MCI subjects compared to mild AD and Nold subjects. These five EEG sources presented both linear and nonlinear (linear, exponential, logarithmic, and power) correlations with the global cognitive level (as revealed by mini mental state examination score) across all subjects. CONCLUSIONS: Cortical EEG rhythms change in pathological aging as a function of the global cognitive level. SIGNIFICANCE: The present functional data on large populations support the 'transitional hypothesis' of a shadow zone across normality, pre-clinical stage of dementia (MCI), and AD. 相似文献
37.
38.
Antinori Andrea Cingolani Antonella Lorenzini Patrizia Giancola Maria Letizia Uccella Ilaria Bossolasco Simona Grisetti Susanna Moretti Francesca Vigo Beniamino Bongiovanni Marco Del Grosso Bruno Arcidiacono Maria Irene Fibbia Giovanni Carlo Mena Maurizio Finazzi Maria Grazia Guaraldi Giovanni Ammassari Adriana Monforte Antonella dArminio Cinque Paola De Luca Andrea 《Journal of neurovirology》2003,9(1):47-53
Human immunodeficiency virus (HIV)-associated progressive multifocal leukoencephalopathy (PML) remains a relevant clinical problem even in the era of highly active antiretroviral therapy (HAART). Aims of the study were to analyze clinical and treatment-related features and the survival probability of PML patients observed within the Italian Registry Investigative Neuro AIDS (IRINA) during a 29-month period of HAART. Intravenous drug use, the presence of focal signs, and the involvement of white matter at neuroradiology increased the risk of having PML. A reduced probability of PML was observed when meningeal signs were reported. Patients starting HAART at PML diagnosis and previously naïve for antiretrovirals showed significantly higher 1-year probability of survival (.58), compared to those continuing HAART (.24), or never receiving HAART (.00). Higher CD4 cell count were associated with a higher survival probability (.45). At multivariate analysis, a younger age, higher CD4, starting HAART at PML diagnosis, the absence of previous acquired immunodeficiency syndrome (AIDS)-defining events, and the absence of a severe neurologic impairment were all associated with a reduced hazard of death. The use of cidofovir showed a trend towards a reduced risk of death. 相似文献
39.
40.
Giovanni Romussi Brunella Parodi Cosimo Pizza Nunziatina De Tommasi 《Archiv der Pharmazie》1994,327(10):643-645
Constituents of Fagaceae (Cupuliferae), XIX: Triterpene Saponins and Acylated Flavonoids from Quercus robur L. var. stenocarpa Beck. In addition to four known glycosides from leaves of Quercus robur L. var. stenocarpa Beck. a new triterpene saponin has been isolted and identified as 28-β-d-glucopyranosyl ester of the 2α,3β,19α-trihydroxy-olean-12-ene-24,28-dioic acid ( I ). 相似文献