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1.
Luis Gandía Baldomero Lara Julita S. Imperial Mercedes Villarroya Almudena Albillos Rosario Maroto A. G. García Baldomero M. Olivera 《Pflügers Archiv : European journal of physiology》1997,435(1):55-64
The characteristics of the binding sites for the Conus magus toxins ω-conotoxin MVIIC and ω-conotoxin MVIID, as well as their effects on K+-evoked 45Ca2+ entry and whole-cell Ba2+ currents (I
Ba), and K+-evoked catecholamine secretion have been studied in bovine adrenal chromaffin cells. Binding of [125I] ω-conotoxin GVIA to bovine adrenal medullary membranes was displaced by ω-conotoxins GVIA, MVIIC and MVIID with IC50 values of around 0.1, 4 and 100 nM, respectively. The reverse was true for the binding of [125I] ω-conotoxin MVIIC, which was displaced by ω-conotoxins MVIIC, MVIID and GVIA with IC50 values of around 30, 80 and 1.200 nM, respectively. The sites recognized by ω-conotoxins MVIIC and MVIID in bovine brain
exhibited higher affinities (IC50 values of around 1 nM). Both ω-conotoxin MVIIC and MVIID blocked I
Ba by 70–80%; the higher the [Ba2+]o of the extracellular solution the lower the blockade induced by ω-conotoxin MVIIC. This was not the case for ω-conotoxin
MVIID; high Ba2+ (10 mM) slowed down the development of blockade but the maximum blockade achieved was similar to that obtained in 2 mM Ba2+. A further difference between the two toxins concerns their reversibility; washout of ω-conotoxin MVIIC did not reverse the
blockade of I
Ba while in the case of ω-conotoxin MVIID a partial, quick recovery of current was produced. This component was irreversibly
blocked by ω-conotoxin GVIA, suggesting that it is associated with N-type Ca2+ channels. Blockade of K+-evoked 45Ca2+ entry produced results which paralleled those obtained by measuring I
Ba. Thus, 1 μM of each of ω-conotoxin GVIA and MVIIA inhibited Ca2+ uptake by 25%, while 1 μM of each of ω-conotoxin MVIIC and MVIID caused a 70% blockade. K+-evoked catecholamine secretory responses were not reduced by ω-conotoxin GVIA (1 μM). In contrast, at 1 μM both ω-conotoxin
MVIIC and MVIID reduced the exocytotic response by 70%. These data strengthen the previously established conclusion that Q-type
Ca2+ channels that contribute to the regulation of secretion and are sensitive to ω-conotoxins MVIIC and MVIID are present in
bovine chromaffin cells. These channels, however, seem to possess binding sites for ω-conotoxins MVIIC and MVIID whose characteristics
differ considerably from those described to occur in the brain; they might represent a subset of Q-type Ca2+ channels or an entirely new subtype of voltage-dependent high-threshold Ca2+ channel.
Received: 16 April 1997 / Received after revision: 10 July 1997 / Accepted: 23 July 1997 相似文献
2.
3.
Isaac S. Gomes-Filho Julita Maria F. Coelho Samilly S. Miranda Simone S. Cruz Soraya C. Trindade Eneida M.M. Cerqueira Johelle S. Passos-Soares Maria da Conceição N. Costa Maria Isabel P. Vianna Ana Cláudia M.G. Figueiredo Alexandre Marcelo Hintz Amanda F. Coelho Luiz Carlos S. Passos Maurício L. Barreto Frank Scannapieco 《Journal of periodontology》2020,91(11):1444-1452
4.
Marek Pawlikowski Maria Jaranowska Hanna Pisarek Robert Kubiak Julita Fuss-Chmielewska Katarzyna Winczyk 《Archives of Medical Science》2015,11(6):1314-1317
Introduction
In normal conditions follicle-stimulating hormone receptors (FSHR) are expressed in the ovary and the testis. They can also be expressed in gonadal tumors. However, recently we have found FSHR immunostaining in pituitary adenomas, adrenal tumors and neuroendocrine tumors (carcinoids). The aim of this study was to determine whether the same occurs in thyroid tumors.Material and methods
Thirty-six samples of surgically excised thyroids were examined. Follicle-stimulating hormone receptors immunostaining was performed on paraffin sections using the rabbit anti-human FSHR polyclonal antibody raised against a 1-190 amino acid sequence from the human FSHR (sc-13935, Santa Cruz).Results
Normal thyroid follicles do not show immunopositivity for FSHR. The same concerns the majority of benign lesions, diagnosed as hyperplasia nodularis or thyroid adenomas. However, positive FSHR immunostaining in some follicles was observed. In all but one thyroid cancer (15 papillary, 10 follicular cancers and one case of anaplastic thyroid cancer) 10–100% of tumor cells exhibit positive FSHR immunostaining. In about 40% of samples FSHR immunoreactivity can be observed also in the endothelia of intrathyroidal blood vessels. This immunopositivity was more frequent in the samples of thyroid cancers (13/27) than in benign lesions (2/9).Conclusions
Ectopic positive FSHR immunostaining is also present in thyroid cancers, and, to a lesser degree, in benign lesions but not in the normal thyroid epithelium. 相似文献5.
6.
Lafuente MP Villegas-Pérez MP Mayor S Aguilera ME Miralles de Imperial J Vidal-Sanz M 《Experimental eye research》2002,74(2):181-189
The purpose of this study was to investigate the dose-response effects of topically administered brimonidine (BMD) on retinal ganglion cell (RGC) survival, short and long periods of time after transient retinal ischemia. In adult Sprague-Dawley rats, RGCs were retrogradely labeled with the fluorescent tracer fluorogold (FG) applied to both superior colliculi. Seven days later, the left ophthalmic vessels were ligated for 90 min. One hr prior to retinal ischemia, two 5 microl drops of saline alone or saline containing 0.0001, 0.001, 0.01 or 0.1% BMD were instilled on the left eye. Rats were processed 7, 14 or 21 days later and densities of surviving RGCs were estimated by counting FG-labeled RGCs in 12 standard regions of each retina. The following have been found. (1) Seven days after 90 min of transient ischemia there is loss of approximately 46% of the RGC population. (2) topical pre-treatment with BMD prevents ischemia-induced RGC death in a dose-dependent manner. Administration of 0.0001% BMD resulted in the loss of approximately 37% of the RGC population and had no significant neuroprotective effects. Administration of higher concentrations of BMD (0.001 or 0.01%) resulted in the survival of 76 or 90%, respectively, of the RGC population, and 0.1% BMD fully prevented RGC death in the first 7 days after ischemia. (3) Between 7 and 21 days after ischemia there was an additional slow cell loss of approximately 25% of the RGC population. Pre-treatment with 0.1% BMD also reduced significantly this slow cell death. These results indicate that the neuroprotective effects of BMD, when administered topically, are dose-dependent and that the 0.1% concentration achieves optimal neuroprotective effects against the early loss of RGCs. Furthermore, this concentration is also effective to diminish the protracted loss of RGCs that occurs with time after transient ischemia. 相似文献
7.
In view of neuroprotective effects of neurotrophins and neurotrophic factors on the damaged nervous tissue clinical attempts have been made to use these proteins in the treatment of neurodegenerative diseases. However, the attempts were unsuccessful. We discuss the main causes of this failure and outline a new clinical prospect due to the growing understanding of the mechanisms underlying neurotrophin activity in the nervous system. A special emphasis has been laid on advances in the research aimed at optimization of pharmacodynamics of neurotrophins, and at development of new delivery systems that would not only supplement the nervous system with required neurotrophins locally, but also regulate their quantity and time span of their delivery. An alternative method of physical exercise allowing to upregulate neurotrophins and their receptors is also discussed. 相似文献
8.
Background: Encephalocraniocutaneous lipomatosis (ECCL) is a relatively new, nonhereditary, but congenital, neurocutaneous
syndrome with unilateral cutaneous tumors and ipsilateral ophthalmologic and neurologic malformations. The syndrome is rare,
with only 25 cases reported since first communication in 1970. The primary clinical features noted for almost all cases are
as follows: (1) unilateral porencephalic cysts with cortical atrophy, (2) ipsilateral lipomatous hamartoma of the scalp, eyelids,
and outer globe of the eye, (3) cranial asymmetry, (4) marked developmental delay and mental retardation, (5) seizures, and
(6) spasticity of the contralateral limbs. Objective: We discuss underlying pathophysiology, diagnostic difficulties, differential
diagnosis, and therapeutic possibilities of the syndrome. Conclusions: The syndrome seems to be more frequent than it was
thought. ECCL may remain unrecognized, as some patients may not represent the full clinical spectrum of the disease. Periodic
neurologic and cardiologic assessment with echocardiography and electrocardiography should be carried out in all patients
with ECCL because of a possible progressive disease course. 相似文献
9.
Exercise increases mRNA levels for adhesion molecules N-CAM and L1 correlating with BDNF response 总被引:2,自引:0,他引:2
Macias M Fehr S Dwornik A Sulejczak D Wiater M Czarkowska-Bauch J Skup M Schachner M 《Neuroreport》2002,13(18):2527-2530
In situ hybridization was used to evaluate whether long-term moderate locomotor exercise, which up-regulates BDNF and TrkB levels in the spinal gray matter of the adult rat, similarly influences the expression of the cell adhesion molecules N-CAM and L1. Exercise doubled the level of N-CAM mRNA hybridization signal in the lumbar spinal gray. The increase in L1 mRNA was less consistent. N-CAM mRNA levels slightly increased in the white matter. BDNF mRNA levels also increased in cells of the ventral horn and the white matter due to the exercise. These results suggest that exercise-induced rearrangements of the spinal network involve N-CAM, L1 and BDNF, crucial in different aspects of synaptic plasticity and synapse formation. 相似文献
10.