全文获取类型
收费全文 | 208篇 |
免费 | 11篇 |
专业分类
耳鼻咽喉 | 3篇 |
儿科学 | 3篇 |
妇产科学 | 2篇 |
基础医学 | 42篇 |
口腔科学 | 1篇 |
临床医学 | 22篇 |
内科学 | 41篇 |
皮肤病学 | 2篇 |
神经病学 | 38篇 |
特种医学 | 3篇 |
外科学 | 21篇 |
预防医学 | 22篇 |
眼科学 | 4篇 |
药学 | 6篇 |
肿瘤学 | 9篇 |
出版年
2022年 | 4篇 |
2021年 | 7篇 |
2020年 | 3篇 |
2019年 | 11篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 8篇 |
2014年 | 7篇 |
2013年 | 24篇 |
2012年 | 22篇 |
2011年 | 20篇 |
2010年 | 12篇 |
2009年 | 8篇 |
2008年 | 10篇 |
2007年 | 9篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 8篇 |
2002年 | 7篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1993年 | 2篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
排序方式: 共有219条查询结果,搜索用时 15 毫秒
1.
2.
Select types of supporting cell in the inner ear express aquaporin-4 water channel protein 总被引:14,自引:0,他引:14
Yutaka Takumi Erlend Arnulf Nagelhus Jo Eidet Atsushi Matsubara Shin-ichi Usami Hideichi Shinkawa Søren Nielsen Ole Petter Ottersen 《The European journal of neuroscience》1998,10(12):3584-3595
Aquaporins (AQPs) confer a high water permeability on cell membranes and play important parts in secretory and absorptive epithelia in kidney and other organs. Here we investigate whether AQPs are expressed in the sensory epithelia of the inner ear, where a precise volume regulation is crucial. By use of specific antibodies it was found that the inner ear contains AQP1 and 4 while being devoid of detectable levels of AQP2, 3 or 5. Immunofluorescence and postembedding immunogold labelling revealed a strictly non-epithelial distribution of AQP1, confirming previous data. In contrast, AQP4 protein and mRNA (visualized by in situ hybridization) were concentrated in select types of supporting cell, including Hensen's cells and inner sulcus cells. Immunogold particles signalling AQP4 were confined to the basolateral plasma membrane of Hensen's cells and to the basal plasma membrane of Claudius cells and inner sulcus cells. AQP4 was also found in supporting cells of the vestibular end organs, but was absent from transitional epithelial cells and dark cells. Strong labelling for AQP4 and AQP4-mRNA was associated with the central part of the cochlear and vestibular nerves. Hair cells were consistently unlabelled. Our findings indicate that AQP4 may facilitate osmotically driven water fluxes in the sensory epithelia of the inner ear and thus contribute to the volume and ion homeostasis at these sites. 相似文献
3.
Nianhui Zhang Jon Laake Erlend Nagelhus Jon Storm-Mathisen Ole Petter Ottersen 《Anatomy and embryology》1991,184(3):213-223
Summary The cellular and subcellular localization of glutamine, a major glutamate precursor, was studied by means of an antiserum raised against glutaraldehydefixed glutamine. Ultrathin sections from the cerebellar cortex of rat and baboon (Papio anubis) were incubated sequentially in the primary antiserum and in a secondary antibody coupled to colloidal gold particles. The labelling intensity was quantified by computer-aided calculation of gold particle densities. High levels of immunoreactivity occurred in glial cells (Bergmann fibres, astrocytes, and oligodendrocytes), intermediate levels in cell bodies and processes of granule cells, and low levels in terminals of presumed GABAergic or glutamatergic fibres (terminals of basket and Golgi cells, and of parallel, mossy, and climbing fibres). The labelling intensity of Purkinje cells showed some variation, but never exceeded that in glial cells. Within the nerve fibre terminals, the glutamine-like immunoreactivity showed some preference for mitochondria, but was otherwise evenly distributed. The predominant glial localization of glutamine was also obvious in light microscopic preparations processed according to the postembedding peroxidase-antiperoxidase procedure. Gold particle densities over different types of profile in glutamine immunolabelled sections were compared with particle densities over the corresponding types of profiles in neighbouring sections labelled with an antiserum to glutaraldehyde-fixed glutamate. The glutamate/glutamine ratio, expressed arbitrarily by the ratio between the respective gold particle densities, varied by a factor of about 6, with the highest ratio in the putative glutamatergic mossy and parallel fibre terminals, and the lowest ratio in glial elements. The remaining tissue components displayed intermediate ratios. The present study provides direct morphological evidence for the existence in the brain of distinct compartments with differing glutamate/glutamine ratios.This paper is dedicated to Professor Fred Walberg on the occasion of his 70th birthdayOn leave of absence from Department of Anatomy, Capital Institute of Medicine, You An Men Street, Beijing, China 相似文献
4.
Jensen J Brennesvik EO Bergersen H Oseland H Jebens E Brørs O 《Pflügers Archiv : European journal of physiology》2002,444(1-2):213-219
In the present study, the density of cell surface beta-adrenergic receptors was determined in different skeletal muscles using the hydrophilic ligand [3H]CGP 12177. The density of beta-adrenergic receptors was highest in the slow-twitch soleus muscle (32.8+/-0.9 fmol mg dw(-1)) and lowest in the fast-twitch glycolytic white gastrocnemius (10.4+/-0.5 fmol mg dw(-1)) beta-Adrenoceptor density correlated closely with the percentage of type-I fibres (r=0.979; P<0.0001) and inversely with the percentage of type-IIB fibres (r=696; P<0.03). Incubation with isoprenaline (10 microM) for 30 min decreased the density of beta-adrenergic receptors in the cell surface from 32.9+/-0.8 to 19.3+/-0.7 fmol mg dw(-1) in the soleus and from 16.8+/-1.0 to 12.0+/-0.7 fmol mg dw(-1) in the epitrochlearis. Internalisation appeared rapid (half-time less than 5 min). To study externalisation of beta-adrenergic receptors, soleus strips were incubated 30 min with 10 microM isoprenaline and then transferred to buffer without agonist. The first incubation reduced the density to approximately 50%, the subsequent incubation without agonist increased cell surface receptor density to approximately 80% of the initial density after 1 h. No further increase was observed over the next 2 h, suggesting that some of the receptors had been degraded. Insulin or contractile activity did not influence rate of externalisation. 相似文献
5.
Wahlin BE Yri OE Kimby E Holte H Delabie J Smeland EB Sundström C Christensson B Sander B 《British journal of haematology》2012,156(2):225-233
The prognostic value of grading follicular lymphoma has been debated since the 1980s. There is consensus that World Health Organization (WHO) grades 1 and 2 are indolent, but not whether grades 3A or 3B are aggressive. We retrospectively reviewed the follicular lymphoma diagnoses according to the 2008 WHO classification in all diagnostic specimens from a population-based cohort of 505 patients with a median follow-up time of 10·0years (range, 4·6-16·0). After excluding 43 patients with concomitant diffuse large B-cell lymphoma, 345 remained with grade 1-2, 94 with grade 3A, and 23 with grade 3B follicular lymphoma. Grades 1-2 and 3A seemed equally indolent, with indistinguishable clinical courses, even in patients receiving anthracyclines. Compared with grades 1-3A and independently of clinical factors, grade 3B correlated with higher mortality (P=0·008), but outcome was improved after upfront anthracycline-containing therapy (P=0·015). In contrast to grade 1-3A patients, grade 3B patients experienced no relapses or deaths beyond 5years of follow-up. Furthermore, patients with grade 3B were predominantly male and seldom presented with bone-marrow involvement. We conclude that follicular lymphoma grade 1-3A is indolent and incurable with conventional therapy. Grade 3B appears to be an aggressive but curable disease. 相似文献
6.
Bjørn K. Erikstein Harald Holte Stein Kvaløy Kristin B. Andersson Harald B. Steen Einar Hannisdal Erlend B. Smeland 《British journal of haematology》1993,83(3):392-398
Summary. Several studies have shown that cell cycle related parameters including DNA synthesis and activation antigen expression can predict patient survival in lymphoma patients. In this study of 69 malignant B cell lymphomas we have examined the cell surface expression of several cell interaction and activation molecules by flow cytometry. Expression of CD18 (integrin β2 chain) was found to correlate strongly with patient survival (median follow up 50 months) even when adjusting for other important prognostic factors ( P = 0.0001). The percentage of cells positive for CDw75 proved important both as a single parameter and in the multivariate analysis. Histology, classified as low versus high grade malignancy, bulky versus not bulky disease and high versus low thymidine incorporation, was also found to correlate with prognosis in this study. 相似文献
7.
Heidi M. Haraldsen Bård Erlend Solstad Andreas Ivarsson Hallgeir Halvari Frank E. Abrahamsen 《Scandinavian journal of medicine & science in sports》2020,30(4):754-765
The present study examined whether there were different growth profiles in basic need frustration in elite junior performers over a nine-month period. Subsequently, we examined whether the identified growth profiles differed in their levels of perfectionistic strivings and evaluative concerns measured at baseline and, additionally, whether they were associated with higher or lower levels of anxiety and perceived performance level in the end of the period. A sample of 259 (Mage = 17.31; SDage = 0.97) elite junior performers from sports and performing arts completed an online questionnaire to report their self-ratings of the study variables. The analyses were conducted using growth mixture modeling in Mplus 8.0. Two main contrasting growth profiles were identified in each of the basic need frustration. Perfectionistic strivings were overall higher than evaluative concerns, but did not differ between the growth profiles. Conversely, evaluative concerns differed significantly between the identified growth profiles. Higher levels of evaluative concerns were associated with the most maladaptive growth profiles. Indeed, elite junior performers, who experienced moderate and increasing levels of competence and autonomy frustration, reported higher levels of anxiety and lower levels of perceived performance level than those who reported low and decreasing levels of competence and autonomy frustration. Based on these findings, evaluative concerns and basic need frustration appear to play key roles in the development of maladaptive motivational processes over time. 相似文献
8.
Mia C. Hikke Stine Braaen Stephane Villoing Kjartan Hodneland Corinne Geertsema Lisa Verhagen Petter Frost Just M. Vlak Espen Rimstad Gorben P. Pijlman 《Vaccine》2014
Salmonid alphavirus (SAV; also known as Salmon pancreas disease virus; family Togaviridae) causes pancreas disease and sleeping disease in Atlantic salmon and rainbow trout, respectively, and poses a major burden to the aquaculture industry. SAV infection in vivo is temperature-restricted and progeny virus is only produced at low temperatures (10–15 °C). Using engineered SAV replicons we show that viral RNA replication is not temperature-restricted suggesting that the viral structural proteins determine low-temperature dependency. The processing/trafficking of SAV glycoproteins E1 and E2 as a function of temperature was investigated via baculovirus vectors in Sf9 insect cells and by transfection of CHSE-214 fish cells with DNA constructs expressing E1 and E2. We identified SAV E2 as the temperature determinant by demonstrating that membrane trafficking and surface expression of E2 occurs only at low temperature and only in the presence of E1. Finally, a vaccination-challenge model in Atlantic salmon demonstrates the biological significance of our findings and shows that SAV replicon DNA vaccines encoding E2 elicit protective immunity only when E1 is co-expressed. This is the first study that identifies E2 as the critical determinant of SAV low-temperature dependent virion formation and defines the prerequisites for induction of a potent immune response in Atlantic salmon by DNA vaccination. 相似文献
9.
Stephen Hewitt Sjur Humerfelt Torgeir T. Søvik Erlend T Aasheim Hilde Risstad Jon Kristinsson Tom Mala 《Obesity surgery》2014,24(5):705-711
Background
Obesity is associated with reduced pulmonary function. We evaluated pulmonary function and status of asthma and obstructive sleep apnoea syndrome (OSAS) before and 5 years after bariatric surgery.Methods
Spirometry was performed at baseline and 5 years postoperatively. Information of asthma and OSAS were recorded. Of 113 patients included, 101 had undergone gastric bypass, 10 duodenal switch and 2 sleeve gastrectomy.Results
Eighty (71 %) patients were women, mean preoperative age was 40 years and preoperative weight was 133 kg in women and 158 kg in men. Five years postoperatively, weight reduction was 31 % (42 kg; p?<?0.001) in women and 24 % (38 kg; p?<?0.001) in men. Forced expiratory volume in 1 s (FEV1) increased 4.1 % (116 ml; p?<?0.001) in women and 6.7 % (238 ml; p?=?0.003) in men. Forced vital capacity (FVC) increased 5.8 % (209 ml; p?<?0.001) in women and 7.6 % (349 ml; p?<?0.001) in men. Gender and weight loss were independently associated with the improvements in FEV1 and FVC. At follow-up, FEV1 had increased 36 % of the difference towards the estimated normal FEV1, and there was a corresponding 70 % recovery of FVC. These improvements occurred despite an expected decline in pulmonary function by age during the study period. Of the asthmatics and OSAS patients, 48 and 80 %, respectively, were without symptoms 5 years postoperatively.Conclusions
Pulmonary function measured with spirometry was significantly improved 5 years after bariatric surgery, despite an expected age-related decline during this period. Symptoms of asthma and OSAS also improved. 相似文献10.
Human and mouse cortical astrocytes differ in aquaporin‐4 polarization toward microvessels
下载免费PDF全文
![点击此处可从《Glia》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Vigdis Andersen Eidsvaag Rune Enger Hans‐Arne Hansson Per Kristian Eide Erlend A. Nagelhus 《Glia》2017,65(6):964-973
Aquaporin‐4 (AQP4), the predominant water channel in the brain, is expressed in astrocytes and ependymal cells. In rodents AQP4 is highly polarized to perivascular astrocytic endfeet and loss of AQP4 polarization is associated with disease. The present study was undertaken to compare the expression pattern of AQP4 in human and mouse cortical astrocytes. Cortical tissue specimens were sampled from 11 individuals undergoing neurosurgery wherein brain tissue was removed as part of the procedure, and compared with cortical tissue from 5 adult wild‐type mice processed similarly. The tissue samples were immersion‐fixed and prepared for AQP4 immunogold electron microscopy, allowing quantitative assessment of AQP4's subcellular distribution. In mouse we found that AQP4 water channels were prominently clustered around vessels, being 5 to 10‐fold more abundant in astrocytic endfoot membranes facing the capillary endothelium than in parenchymal astrocytic membranes. In contrast, AQP4 was markedly less polarized in human astrocytes, being only two to three‐fold enriched in astrocytic endfoot membranes adjacent to capillaries. The lower degree of AQP4 polarization in human subjects (1/3 of that in mice) was mainly due to higher AQP4 expression in parenchymal astrocytic membranes. We conclude that there are hitherto unrecognized species differences in AQP4 polarization toward microvessels in the cerebral cortex. 相似文献