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排序方式: 共有177条查询结果,搜索用时 15 毫秒
31.
32.
Felice Petraglia Antonio Alberto de Micheroux Pasquale Florio Michela Salvatori Andrea Gallinelli Vito Cela Marco Antonio Palumbo Andrea Riccardo Genazzani 《The Journal of steroid biochemistry and molecular biology》1995,53(1-6):227-231
Human placenta produces a large variety of bioactive substances with endocrine and neural competence: pituitary and gonadal hormones, hypothalamic-like releasing or inhibiting hormones, growth factors, cytokines and neuropeptides. The most recent findings indicate that locally produced hormones regulate the secretion of other placental hormones supporting a paracrine/autocrine regulation. In placental endocrinology, a particular relevance is played by steroid hormones. In fact, a specific gonadotropin-releasing hormone (GnRH)-human chorionic gonadotropin (hCG) regulation of placental steroidogenesis has been proposed as a placental internal regulatory system acting on steroids production from human placenta. In addition, activin and inhibin have been proposed as further regulatory substances of the synthesis and secretion of steroids; the addition of activin A to placental culture augments GnRH, hCG and progesterone, and this effect can be significantly reduced by the addition of inhibins. Finally, a steroid-steroid interaction is suggested by the evidence that placental estrogen has a positive role in the regulation of progesterone biosynthesis. Other steroid-protein interactions have been observed in human placenta. In fact, recent data indicate that progesterone inhibits placental corticotropin-releasing factor (CRF) and estrogens act on placental conversion of cortisol to cortisone, activating cortisol secretion by the fetal adrenal and enhancing fetal adrenal function with advancing gestation. 相似文献
33.
Retinopathy of prematurity (ROP) is a vasoproliferative disorder that occurs in premature infants and may lead to permanent visual impairment. We investigated both the possible protective role of N-acetyl cysteine (NAC) for preventing ROP and the role of IGF-1 in the disorder. Forty-five newborn rats were divided into three groups. Group 1 was raised in room air as controls. Group 2 was exposed to 60% oxygen for 14 days after birth, then transferred to room air. Group 3 was exposed to the same conditions as group 2, but received intraperitoneal injections of NAC on postnatal days 7–17. After 35 days, both eyes of all rats were processed for histology. Some sections were stained with hematoxylin and eosin to assess structural changes and other sections were immunostained to determine the location of IGF-1. Frozen sections also were prepared and stained for adenosine triphosphatase to detect retinal blood vessels. Compared to the controls, more blood vessels, many of which were abnormal, and increased IGF-1 expression were observed in group 2. In group 3, abnormal blood vessels and IGF-1 expression were less evident. NAC appeared to be an effective vascular-protective agent for ROP by decreasing IGF-1 expression. 相似文献
34.
P Inaudi V De Leo M De Leo G Verzetti N D'Antona A R Genazzani 《Bollettino della Società italiana di biologia sperimentale》1983,59(12):1861-1867
The present study points out that the CHRONIC RENAL FAILURE (CRF) represents a situation of decreased adrenal function: at least for delta 5 Steroids which are markedly reduced when compared with normal subjects. Peripheral plasma levels of Pregnenolone (delta 5 P) ranged in CRF between 190 and 860 pg/ml; Dehydroepiandrosterone-sulphate (DHA-S) 0.1-2.2 ng/ml and Dehydroepiandrosterone (DHA) 200-3100 pg/ml. Cortisol was in the normal range or slightly elevated (70-175 ng/ml). A significant correlation between basal concentration and the time of dialysis was observed. It is interesting to notice how the phase levels of delta 5 P, DHA-S and DHA are reduced ad from the beginning of the haemodialysis treatment and that during such a treatment a further progressive decrease occurs reaching concentrations with are similar to those found in pre-puberty. This phenomenon appears to be the evidence of a progressive metabolic involution of the adrenal gland due to the exhaustion of enzymatic activities and of receptorial structures. Furthermore, these results suggest speculation on interrelationship between adrenal and gonadal activity in these patients. 相似文献
35.
D Scavo F Facchinetti C Barletta F Petraglia R Buzzetti M Monaco C Giovannini R Genazzani 《Hormones et métabolisme》1987,19(5):204-207
In order to clarify the possible interaction between endogenous opioids and glucose homeostasis in obesity we studied Beta-Endorphin (B-Ep), ACTH, cortisol and insulin plasma levels in response to an oral glucose tolerance test (OGTT) in 8 females suffering from uncomplicated obesity and in 6 healthy volunteers of normal weight. Results were evaluated in terms of secretion areas subtracted from basal value. Basal glucose, insulin and B-Ep levels were significantly higher in the obese patients compared to controls, cortisol levels and ACTH were not statistically different between obese and normal subjects. During OGTT total areas of insulin secretion were significantly higher in the obese patients; cortisol, ACTH, B-Ep plasma levels did not change in controls, whereas obese patients showed a response to B-Ep which reached a peak at 60 minutes. The area of B-Ep response to OGTT in obese patients was significantly higher than in controls. On the basis of these results we may suggest that the opioid system belongs to the chain of neuroendocrine and metabolic events responsible for the origin and the growth of overweight. But the possibility exists that obesity itself can enhance the B-Ep secretion above all through overeating. In this regard it is to stress that glucose ingestion induces in obese patients, differently from normal subjects, insulin hypersecretion and the B-Ep secretion, possibly from gastro-enteric tract and/or pancreatic isles. 相似文献
36.
Simultaneous circadian variations of plasma ACTH, beta-lipotropin, beta-endorphin and cortisol 总被引:1,自引:0,他引:1
F Petraglia F Facchinetti D Parrini G Micieli S De Luca A R Genazzani 《Hormone research》1983,17(3):147-152
The major objective of this study was to investigate the analogy existing between the typical circadian periodicity of ACTH and that recently described of beta-lipotropin (beta-LPH) and beta-endorphin (beta-EP) plasma levels. The determination of their concentrations, plus cortisol, has been performed on the same plasma samples of 6 healthy volunteers. All hormones were measured by radioimmunoassay. Those of beta-LPH and beta-EP were preceded by a purification of plasma through silicic acid extraction and Sephadex G-75 gel filtration. The highest values (mean +/- SEM) were found in the morning (ACTH: 10.3 +/- 0.9; beta-LPH; 6.3 +/- 0.7; beta-EP: 6.5 +/- 0.5 fmol/ml; cortisol: 378 +/- 30 pmol/ml) and the lowest values in the evening (ACTH: 6:1 +/- 0.7; beta-LPH: 3.3 +/- 0.4; beta-EP: 3.7 +/- 0.6 fmol/ml; cortisol: 130 +/- 23 pmol/ml). Statistical analysis using the Fourier method led to the evidence of a concomitant circadian secretory pattern of the three proopiocortin-related peptides. These results strongly suggest that the phasic secretion of ACTH, beta-LPH and beta-EP underlies a common central control. 相似文献
37.
Central ACTH deficit in degenerative and vascular dementia 总被引:1,自引:0,他引:1
F Facchinetti G Nappi F Petraglia E Martignoni E Sinforiani A R Genazzani 《Life sciences》1984,35(16):1691-1697
Cerebrospinal fluid (CSF) concentrations of ACTH, beta-lipotropin (beta-LPH) and beta-endorphin (beta-EP) were measured in 15 patients affected by dementia, who underwent also a brain computerized tomography (CT), and in 13 age-matched healthy volunteers. ACTH CSF levels of patients (4.0 +/- 2.4 fmol/ml, M +/- SD) were significantly lower than in controls (9.8 +/- 5.0, P less than 0.01) the lowest values being found in Alzheimer type of dementia (ATD: 3.1 +/- 2.5) and in patients with radiological evidence of cortical atrophy (2.5 +/- 1.2), independently of the probable origin of dementia. Although beta-LPH and beta-EP levels of patients fell within normal range, they were lower in ATD than in dementia sustained on a vascular origin. There was no variation of either peptides concentration in relation to CT findings. These data indicate the ACTH impairment as typical of dementia, supporting in humans the positive role of this peptide on learning and mnesic functions. Moreover, the maintained CSF levels of both beta-LPH and beta-EP in the dementia sustained on a vascular origin, while lower values were found in ATD, could represent a differentiation between vascular and degenerative diseases of the Central Nervous System (CNS). 相似文献
38.
F Facchinetti S Bernasconi F Petraglia C Marcellini L Iughetti A R Genazzani 《Hormones et métabolisme》1988,20(6):348-351
Plasma B-Endorphin (B-EP), Growth Hormone (GH) and cortisol response to 100 mcg/m2 b.s., i.v. clonidine (an alpha 2-adrenergic agonist) were evaluated in 17 normal weight children (8 prepubertal and 9 pubertal) and in 15 children with simple exogenous obesity (7 prepubertal and 8 pubertal, weight excess ranging from 29% to 97%). All the hormones were measured by radioimmunoassay either directly in the plasma (GH and cortisol) or after extraction and chromatography (B-EP). Obese prepubertal and pubertal children showed basal B-EP levels significantly higher than in controls and no differences were found in GH and cortisol levels. While in controls clonidine stimulated a significant release of plasma GH and B-EP in obese patients, irrespective of pubertal development, no changes were found. Cortisol levels decreased in both groups. These data suggest an impaired adrenergic control of GH and B-EP secretion in children with simple exogenous obesity. 相似文献
39.
Conserved sequences in enzymes of the UDP-GlcNAc/MurNAc family are essential in hamster UDP-GlcNAc:dolichol-P GlcNAc-1-P transferase 总被引:1,自引:0,他引:1
The UDP-GlcNAc/MurNAc family of eukaryotic and prokaryotic enzymes use
UDP-GlcNAc or UDP-MurNAc-pentapeptide as donors, dolichol-P or polyprenol-P
as acceptors, and generate sugar-P-P-polyisoprenols. A series of six
conserved sequences, designated A through F and ranging from 5 to 13 amino
acid residues, has been identified in this family. To determine whether
these conserved sequences are required for enzyme function, various
mutations were examined in hamster UDP- GlcNAc:dolichol-P GlcNAc-1-P
transferase (GPT). Scramble mutations of sequences B-F, generated by
scrambling the residues within each sequence, demonstrated that each is
important in GPT. While E and F scrambles appeared to prevent stable
expression of GPT, scrambling of B- D resulted in GPT mutants that could be
stably expressed and bound tunicamycin, but lacked enzymatic activity.
Further, the C and D scramble mutants had an unexpected sorting defect.
Replacement of sequences B-F with prokaryotic counterparts from either the
B.subtilis mraY or E.coli rfe genes also affected GPT by preventing
expression of the mutant protein (B, F) or inhibiting its enzymatic
activity (C-E). For the C-E replacements, no acquisition of acceptor
activity for polyprenol-P, the fully unsaturated natural bacterial
acceptor, was detected. These studies show that the conserved sequences of
the UDP- GlcNAc/MurNAc family are important, and that the eukaryotic and
prokaryotic counterparts are not freely interchangeable. Since several
mutants were efficiently expressed and bound tunicamycin, yet lacked
enzymatic activity, the data are consistent with these sequences having a
direct role in product formation.
相似文献
40.
JB Parentes-Vieira PV Lopes-Costa CG Pires AR dos Santos JD Pereira-Filho BB da Silva 《International Seminars in Surgical Oncology : ISSO》2007,4(1):22