全文获取类型
收费全文 | 1045篇 |
免费 | 49篇 |
国内免费 | 4篇 |
专业分类
耳鼻咽喉 | 5篇 |
儿科学 | 17篇 |
妇产科学 | 29篇 |
基础医学 | 64篇 |
口腔科学 | 13篇 |
临床医学 | 61篇 |
内科学 | 224篇 |
皮肤病学 | 33篇 |
神经病学 | 231篇 |
特种医学 | 40篇 |
外科学 | 185篇 |
综合类 | 3篇 |
预防医学 | 54篇 |
眼科学 | 4篇 |
药学 | 67篇 |
肿瘤学 | 68篇 |
出版年
2023年 | 9篇 |
2022年 | 17篇 |
2021年 | 27篇 |
2020年 | 16篇 |
2019年 | 22篇 |
2018年 | 29篇 |
2017年 | 16篇 |
2016年 | 22篇 |
2015年 | 16篇 |
2014年 | 34篇 |
2013年 | 36篇 |
2012年 | 49篇 |
2011年 | 51篇 |
2010年 | 26篇 |
2009年 | 34篇 |
2008年 | 47篇 |
2007年 | 43篇 |
2006年 | 57篇 |
2005年 | 38篇 |
2004年 | 45篇 |
2003年 | 41篇 |
2002年 | 30篇 |
2001年 | 30篇 |
2000年 | 33篇 |
1999年 | 47篇 |
1998年 | 10篇 |
1997年 | 13篇 |
1996年 | 9篇 |
1995年 | 11篇 |
1994年 | 5篇 |
1993年 | 12篇 |
1992年 | 29篇 |
1991年 | 25篇 |
1990年 | 23篇 |
1989年 | 13篇 |
1988年 | 11篇 |
1987年 | 23篇 |
1986年 | 14篇 |
1985年 | 10篇 |
1984年 | 15篇 |
1983年 | 4篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1977年 | 5篇 |
1970年 | 4篇 |
1969年 | 5篇 |
1967年 | 6篇 |
1892年 | 3篇 |
排序方式: 共有1098条查询结果,搜索用时 15 毫秒
1.
S. Natoli V. Oliveira P. Calabresi L. F. Maia A. Pisani 《European journal of neurology》2020,27(9):1764-1773
The current coronavirus disease (COVID‐19) outbreak, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), has raised the possibility of potential neurotropic properties of this virus. Indeed, neurological sequelae of SARS‐CoV‐2 infection have already been reported and highlight the relevance of considering the neurological impact of coronavirus (CoV) from a translational perspective. Animal models of SARS and Middle East respiratory syndrome, caused by structurally similar CoVs during the 2002 and 2012 epidemics, have provided valuable data on nervous system involvement by CoVs and the potential for central nervous system spread of SARS‐CoV‐2. One key finding that may unify these pathogens is that all require angiotensin‐converting enzyme 2 as a cell entry receptor. The CoV spike glycoprotein, by which SARS‐CoV‐2 binds to cell membranes, binds angiotensin‐converting enzyme 2 with a higher affinity compared with SARS‐CoV. The expression of this receptor in neurons and endothelial cells hints that SARS‐CoV‐2 may have higher neuroinvasive potential compared with previous CoVs. However, it remains to be determined how such invasiveness might contribute to respiratory failure or cause direct neurological damage. Both direct and indirect mechanisms may be of relevance. Clinical heterogeneity potentially driven by differential host immune‐mediated responses will require extensive investigation. Development of disease models to anticipate emerging neurological complications and to explore mechanisms of direct or immune‐mediated pathogenicity in the short and medium term is therefore of great importance. In this brief review, we describe the current knowledge from models of previous CoV infections and discuss their potential relevance to COVID‐19. 相似文献
2.
M. Bialer A. Haj-Yehia N. Barzaghi F. Pisani E. Perucca 《European journal of clinical pharmacology》1990,38(3):289-291
Summary The pharmacokinetics of a single 400 mg oral dose of valnoctamide (VCD) has been investigated in seven healthy, adult, male volunteers. VCD was not biotransformed rapidly to its corresponding acid valnoctic acid (VCA), unlike its isomer valpromide (VPD). It had a mean residence time of 13.2 h and a terminal half-life of 9.3 h. Throughout the study, only low plasma levels of VCA could be detected. Thus, unlike VPD, which is a prodrug of the corresponding acid, (valproic acid, VPA). VCD appears to act as a drug in its own right, and it does not undergo similar hydrolysis. The pharmacokinetic difference may account for the different pharmacological activities of the two isomers. 相似文献
3.
筛检对肝癌死亡率影响的研究 总被引:5,自引:0,他引:5
5581名HBsAg阳性的男性随机分入周期性筛检组(A组,3712人)及对照组(B组,1869人)。A组(19155.4人年)共发生肝癌257例,B组(9785.5人年)为117例,两组的肝癌发生率分别为1342/10万与1196/10万;两组肝癌死亡分别为218与109例,肝癌死亡率分别为1138/10万与1114/10万。两组中Ⅰ期肝癌病例分别为29.6%与6.0%,差异有非常显著性意义。1、3、5年相对生存率A组为23.7%、7.0%、4.0%,B组为9.7%、4.0%、4.1%。用Poisson回归模型拟合显示,在调正年龄、初筛AFP及入列年份后,筛检对于肝癌的相对危险度为0.83,95%CI为0.68~1.03,有较弱的“保护”作用,Cox回归模型拟合结果显示当临床分期未引入模型时,筛检对于肝癌有显著的“保护”作用:危险率为0.6617,95%CI为0.5234~0.8365;而模型经调整后,危险率即接近“1”,95%CI为0.74~1.26。 相似文献
4.
R Montironi A Santinelli M Scarpelli A Braccischi E Pisani R Alberti 《Pathology, research and practice》1992,188(4-5):504-509
The study was done on cytologic material of 58 non-oxyphil follicular neoplasias of the thyroid, 32 of which were adenomas and 26 carcinomas. Three groups of nucleolar features were quantified using a routine microscope with an ocular micrometer: frequency-, size-, and margination-related features. Since value overlap was present between two categories for all the variables, stepwise discriminant analysis was applied. The following three features were selected by the computer for calculation of one canonical discriminant function: percentage of marginated nucleoli, percentage of nuclei with one nucleolus, mean major nucleolar diameter. The percentage of agreement between morphologic and computer classifications was 95%. Two follicular adenomas were allocated to the carcinoma category, whereas one follicular carcinoma was allocated to the adenoma category. Out of 58, 52 were diagnosed by the computer into one of the two diagnostic categories with a very high probability, i.e. P greater than 0.75, the remaining 6 being considered intermediate. 相似文献
5.
Résumé: La ?coxa pedis? correspond à l'?articulation talo-calcanéo-navicularis?. Structurée comme une énarthrose, il est possible
de lui définir une épiphyse représentée par la tête et le col du talus et une cotyle structurée comme une cavité ostéo-fibro-cartilagineuse,
à la constitution de laquelle concourent, comme éléments squelettiques, la surface articulaire postérieure du naviculaire
et les surfaces articulaires des petites (sustentaculum tali) et grandes apophyses du calcanéus qui forment l'articulation sous-talienne antérieure; parfois divisées entre elles par
un sillon, le plus souvent elles constituent une seule formation articulaire.
La surface articulaire comprise entre le naviculaire, le sustentaculum tali et la grande apophyse du calcanéus est complétée
par un fibro-cartilage gléno?dien renforcé superficiellement par le ligament calcanéo-naviculaire plantaire qui, prenant naissance
à la base et sur le contour antéromédial du sustentaculum tali, s'insère distalement sur le tubercule et le bord inféro-postérieur
du naviculaire. Ce ligament correspond au fond de la coxa pedis et sous-tend une véritable gléno?de, revêtue de cartilage,
en relation articulaire avec le versant inféro-médial de la tête du talus compris entre les versants du naviculaire et du
calcaneus.
De plus, la présence de corpuscules proprioceptifs dans le ligament calcanéo-naviculaire plantaire fait penser à une fonction
réceptrice cybernétique également de la coxa pedis.
Aux stades foetaux précoces (16e-17e semaine), les articulations talo-naviculaire et sous-talienne antérieure sont différenciées dans une unique structure articulaire
présentant des caractéristiques morphologiques d'énarthrose.
Dans un sens plus ample, ?coxa pedis? peut définir la signification fonctionnelle particulière d'une structure qui, de par
ses données anatomiques, évolutives et cliniques, peut être analogiquement comparée à l'articulation coxo-fémorale avec laquelle,
ainsi qu'avec le genou, elle s'intègre fonctionnellement dans la structure plus complexe du membre inférieur.
La différenciation énarthrosique proximale et distale au membre inférieur, avec le joint interposé représenté par le genou,
est une prémisse biomécanique aux mécanismes de rotation (plan orthogonal aux axes segmentaires du membre) indispensables
pour amorcer la stabilisation du membre dans la phase portante (cha?ne cinétique fermée); et, à la succession des mécanismes
intercurrents dans le plan frontal (translation latérale de la charge lors du démarrage de la phase portante) et dans le plan
sagittal (phase oscillante).
Une référence particulière est faite à la pathologie gléno?dienne dégénérative et au syndrome de déstabilisation péritalienne.
Récemment, une référence à la ?coxa pedis? (1999) a été faite dans l'édition mise à jour de l'Encyclopédie Médico-Chirurgicale
rédigée par Biga, Moulies et Mabit.
相似文献
6.
A restricted field of view (rFOV) approach for imaging a dynamic time series of volumes of limited spatial extent within a larger subject is described. The shorter readout with rFOV-MRI can be exploited to either limit image artifacts or increase spatial resolution. To accomplish rFOV imaging of a multislice volume for a dynamic series, an outer volume suppression (OVS) preparation that saturates signal external to a cylinder through the subject is followed by slice-selective excitation and a spiral readout. The pass- and stopband efficiencies of the OVS in an agar gel phantom were 97% (+/-1.5%) and 3% (+/-1%), respectively. Profiles of the temporal signal-to-noise ratio (SNR) were measured in a phantom and an adult brain. The rFOV sequence reduced distortions from off-resonance signal and T2*-induced blurring compared to a conventional sequence. Sequence utility is demonstrated for high-resolution rFOV functional MRI (fMRI) in the visual cortex. The rFOV sequence may prove to be useful for other multislice dynamic and high-resolution imaging applications. 相似文献
7.
V. Belcastro C. Costa F. Galletti F. Pisani P. Calabresi L. Parnetti 《European journal of neurology》2007,14(10):1176-1178
Levetiracetam (LEV) monotherapy was investigated in 25 patients with advanced Alzheimer's disease (AD) and new-onset epileptic seizures in a prospective open-label study. At a daily dose of 1000–1500 mg, 72% were seizure-free for at least one year; 16% discontinued for untolerability; 8% were unresponsive; 4% were lost to follow-up. These results suggest the need for controlled studies to confirm if LEV can be a first-choice drug in AD. 相似文献
8.
Paolo Calabresi Emesto Fedele Antonio Pisani Giovanni Fontana Nicola B. Mercuri Giorgio Bernardi Maurizio Raiteri 《The European journal of neuroscience》1995,7(9):1889-1894
Using a corticostriatal slice preparation, we have recently shown that tetanic stimulation of the corticostriatal pathway produces long-term depression (LTD) of striatal excitatory synaptic transmission. In the present study we have analysed the relationship between LTD and the striatal release of different endogenous transmitters. Samples of perfusate were collected via a small cannula placed just above the surface of the striatal slice close to the recording electrode, and were analysed by HPLC. The high-frequency stimulation (100 Hz, three trains, 3 s duration, 20 s intervals) used to induce LTD caused a significant but transient increase in the release of both excitatory (aspartate and glutamate) and inhibitory (glycine and GABA) amino acid transmitters. Tetanic stimulation also produced a significant, but transient increase in the release of endogenous dopamine. We conclude that the tetanic stimulation of the corticostriatal pathway is able to induce a large but transient release of excitatory amino acids and of dopamine, whose participation in the induction of striatal LTD has been demonstrated previously. Moreover, the maintenance of this form of synaptic plasticity does not seem to require a sustained change in transmitter release. 相似文献
9.
Authors injected a 1.5-2 cc Gax-Collagen into the tongue of 13 rats in order to examine the reactivity of the tissues around the graft and its attitude and duration. The research had practical purposes as the material is mainly used in E.N.T. for reconstructing the vocal cords. The animals have been sacrificed from 1 day to 9 months and the tongue subjected to the ordinary histologic methods. Our conclusions are as follows: a) a moderate inflammatory reaction following the introduction of the foreign body, then it attenuates and disappears at the third month; b) the implant is well tolerated, does not cause structural alterations in the surrounding tissues, in particular in the musculature where it is placed; c) a neovascularization appears, it lessens over the time, keeping itself only at the edge of the graft; d) in the formed fissures, fibroblasts, traces of collagen and neocollagen are present. All these conditions allow for taking root and the persistence of the implant. It is remarkable that the spherical form of the Gax-Collagen does not modify even if it has been implanted into a muscular organ and therefore subjected to severe and continuous mechanical stress. 相似文献
10.
Regional brain distribution of [18F]GBR 13119, a dopamine uptake inhibitor, in CD-1 and C57BL/6 mice
M R Kilbourn M S Haka G K Mulholland P S Sherman T Pisani 《European journal of pharmacology》1989,166(2):331-334
We have examined the regional brain distribution of [18F]GBR 13119 (18F: beta +, T1/2 = 110 min), a dopamine uptake inhibitor, in CD-1 and C57BL/6 mice. High levels of binding are observed in the striatum of both species, with striatum/cerebellum ratios of 3-4 at 60 min after injection of the radiotracer. Striatum radioactivity and striatum/cerebellum ratios are more than 50% reduced in C57BL/6 mice treated chronically with the neurotoxin MPTP. We conclude mice are an appropriate model for the in vivo study of the dopamine uptake system, and that [18F]GBR 13119 may be a suitable in vivo marker for degeneration of striatal dopaminergic neurons. 相似文献