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1.
Oxytocin treatment in rats induces long-lasting antistress and growth promoting effects. This study investigated whether prolyl-leucyl-glycinamide (PLG) (the c-terminal tripeptide of oxytocin) or tocinoic acid (the ring structure of oxytocin) could induce some of these effects in male rats. For this purpose, PLG (2 or 10 mg/kg, s.c.) or tocinoic acid (1 mg/kg, s.c.) was administered to rats once a day for 3 or 5 days. Blood pressure, heart rate, spontaneous motor activity, nociceptive thresholds, and the survival of ischaemic musculocutaneous flaps were measured. In addition, endogenous oxytocin levels and plasma levels of some hormones known to be influenced by oxytocin were determined. PLG (2 mg/kg, s.c., but not 10 mg/kg, s.c.) decreased diastolic blood pressure (p<0.05) and locomotor activity (p<0.05). PLG (10 mg/kg, s.c.) decreased gastrin (p<0.05) and endogenous oxytocin levels in plasma (p<0.01). Tocinoic acid decreased locomotor activity (p<0.05), but did not affect any of the other parameters measured. In conclusion, this study showed that both PLG and tocinoic acid decrease locomotor activity. In addition, PLG also induced some other effects similar to those induced by oxytocin treatment but when administered in high doses it decreased oxytocin levels.  相似文献   
2.
Plasma levels of somatostatin like immunoreactivity (SLI), below referred to as somatostatin levels, were measured in peripheral plasma of conscious dogs. Basal somatostatin levels averaged 49 +/- 10 pM. Somatostatin as well as gastrin and insulin plasma levels were measured before and after feeding with and without prior atropinization. During the first 10 min after feeding somatostatin levels fell from 49 +/- 10 to 23 +/- 9 pM, whereas gastrin and insulin levels rose from 9 +/- 2 and 140 +/- 14 pM to 48 +/- 11 and 370 +/- 91 pM respectively. Atropine 0.01 or 0.1 mg/kg did not inhibit these responses. After the initial decrease, somatostatin level rose again and peaked at around 60 min after feeding (110 +/- 24 pM). This secondary rise was completely abolished by atropine in both doses tried. Gastrin and insulin levels remained elevated throughout the experiments with and without atropine. It is suggested that gastrin release and HCl secretion are inhibited by a tonic outflow of gastric somatostatin during basal conditions. The process of feeding induces an atropine resistant, vagally mediated decrease in somatostatin release from the gastrointestinal tract and this decreased output of somatostatin facilitates initiation of meal-related endocrine and exocrine gastric secretions.  相似文献   
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4.
Blood samples were collected in peripheral venous blood of seven lactating sows, when their piglets were suckling. In four of the experiments samples were also taken when the sows were fed a meal. Gastrin, insulin, somatostatin and VIP levels were measured by radioimmunoassay. Insulin levels increased by approximately 100% for about 10 min in response to suckling, in some experiments even before the suckling occurred, i.e. when the sows saw, heard and smelled their piglets. In four of the sows suckling caused a biphasic twofold increase in gastrin levels - one immediate peak which lasted for a few min and a second peak of longer duration (about 30-60 min), whereas gastrin levels remained unchanged in three animals. Somatostatin levels usually reflected gastrin levels in a reciprocal way. Thus, a biphasic decrease of somatostatin levels occurred in the high gastrin responders. In contrast, somatostatin levels increased in the experiments, in which gastrin levels did not change. Immediate and short-lasting (a few minutes long) increases of VIP levels were also induced by suckling. Large litters and long suckling periods appeared to be related to greater changes of the levels of all the peptides measured. Feeding influenced insulin, gastrin and somatostatin levels in the same way as did suckling from both a qualitative and a quantitative point of view. In contrast, VIP levels were not increased by feeding. The possible functional effects of the suckling-induced release of gastrointestinal hormones and possible mechanisms of their release are discussed.  相似文献   
5.
Recent evidence suggests a regulatory role in the nervous system for somatomedins. The present study, using a somatomedin radioreceptorassay which primarily detects insulin-like growth factors 1 and 2, shows that somatomedins are widely distributed throughout the nervous system of the cat. Whilst somatomedins were present in all CNS regions, the highest concentration occurred in the hypothalamus followed by cerebral cortex. In the spinal cord, the dorsal roots contained twice the concentration found in the ventral roots. Activity was also present in the sympathetic ganglia, vagus nerve and sciatic nerves. Following electrical stimulation of the brachial and sciatic nerves somatomedins were released into perfusates from extirpated cut limbs. These findings suggest that somatomedins may be neuroregulatory hormones.  相似文献   
6.
The aim of the present study was to investigate whether amperozide, an antipsychotic drug which possesses anti-aggressive and anxiolytic-like properties, stimulates the secretion of oxytocin and if so, by which receptor mechanism. For this purpose, female or male Sprague Dawley rats were given amperozide (0.5, 2.5 and 5.0 mg/kg IP), ritanserin (5.0 mg/kg), raclopride (2.0 mg/kg) and prazosin (1.0 mg/kg) and were subsequently decapitated for collection of blood (30 and 120 min) after injection. Oxytocin levels were measured with radioimmunoassay. Amperozide 2.5 and 5 mg/kg increased plasma levels of oxytocin significantly (P<0.05 and <0.001). The effect appeared maximal about 30 min after injection of the drug and oxytocin levels were almost back to basal within 120 min. Similar effects were obtained in female and male rats as well as in animals that were freely fed or food deprived for 24 h. CSF levels of oxytocin were also increased. Ritanserin, a 5-HT2-receptor antagonist but not the D2 receptor antagonist raclopride or the 1-adrenoceptor antagonist prazosin stimulated oxytocin release. In addition, clozapine, a neuroleptic with potent HT2-antagonistic properties, was a potent releaser of oxytocin, whereas haloperidol was without effect. A possible role for oxytocin in the behavioural effects of amperozide and clozapine remains to be explored.  相似文献   
7.
We measured the cord levels of gastrin, somatostatin and oxytocin with radioimmunoassay in plasma collected from the umbilical artery after vaginal delivery and after elective cesarean section. Maternal venous samples after the two labour modalities were also assayed for the same hormones. Fetal gastrin, somatostatin and oxytocin levels were significantly higher after vaginal delivery than after elective cesarean section. Independently of labour type, the fetal gastrin and somatostatin levels were always higher than the maternal levels. We suggest that the observed high levels of gastrin, somatostatin and oxytocin could be due to a stress-related stimulation of the oxytocin- as well as of the gastric gastrin- and somatostatin-producing cells, occurring particularly during vaginal delivery. The significant inverse correlation found between fetal pH and the recorded hormone levels is consistent with this hypothesis.  相似文献   
8.
OBJECTIVES: Fibromyalgia syndrome (FMS) is a chronic pain disorder, where 90% of the patients struck by the disorder are women. The neuropeptide oxytocin is known to have antinociceptive and analgesic, as well as anxiolytic and antidepressant effects, which makes this neuropeptide of interest in fibromyalgia research. The aim of this study was to assess oxytocin concentrations in female FMS patients with different hormonal status and in depressed and non-depressed patients and relate oxytocin concentrations to adverse symptoms as pain, stress, depression, anxiety and to the positive item happiness. METHODS: Thirty-nine patients and 30 controls registered these symptoms daily during 28 days and blood samples for the assessment of oxytocin were drawn twice in all patients and controls. Besides the daily ratings, depression was also estimated with the self-rating instrument Beck Depression Inventory (BDI). RESULTS: Depressed patients according to the BDI differed significantly with low levels of oxytocin compared to the non-depressed patients and the controls. Low levels of oxytocin were also seen in high scoring pain, stress and depression patients according to the daily ratings; however, these subgroups were small. A negative correlation was found between the scored symptoms depression and anxiety and oxytocin concentration, and a positive correlation between the item happiness and oxytocin. The oxytocin concentration did not differ between the hormonally different subgroups of patients or controls. CONCLUSION: The results suggest that the neuropeptide oxytocin may, together with other neuropeptides and neurotransmitters, play a role in the integration of the stress axes, monoaminergic systems and the pain processing peptides in the pathophysiologic mechanisms responsible for the symptoms in the FMS.  相似文献   
9.
The aim of the present study was to investigate whether low-dose oral contraceptives affect oxytocin concentrations in plasma. Twenty women participated in an open cross-over study. Six consecutive blood samples were drawn twice, with a 4-week interval, in the luteal phase of the menstrual cycle when the women were/were not taking oral contraceptives. Plasma levels of oxytocin were analysed with a radio-immunoassay specific for oxytocin. A significant increase in oxytocin concentrations was observed following ingestion of oral contraceptives (p less than 0.02). Women with the highest oxytocin levels during a normal menstrual cycle increased their levels the most when on oral contraceptives. Analysis with high performance liquid chromatography demonstrated that immunoreactive oxytocin found in plasma, whether with or without oral contraceptives, co-eluted with synthetic oxytocin standard. An interesting possibility could be that the mental side effects and effects on glucose metabolism occurring after treatment with oral contraceptives might be related to elevated oxytocin levels, since metabolic and CNS effects of oxytocin are known.  相似文献   
10.
Release of GI hormones in mother and infant by sensory stimulation   总被引:3,自引:0,他引:3  
It is well established that sensory stimulation is of great importance for the growth of and for the physiological and psychological development of infants. Supplementary sensory stimulation such as non-nutritive sucking and tactile stimulation has been shown to increase the growth rate and the maturation of premature infants. In human neonates non-nutritive sucking has a vagally mediated influence on the levels of some gastrointestinal hormones. In animal experiments afferent electrical stimulations of the sciatic nerves at low intensity leads to an activation of the vagal nerves and to a consequent release of vagally controlled gastrointestinal hormones such as gastrin and cholecystokinin. We therefore assume that both non-nutritive sucking and tactile stimulation trigger the activity of sensory nerves which leads to a release of vagally regulated gut hormones. Since gut hormones stimulate gastrointestinal motor and secretory activity and the growth of the gastrointestinal tract, and enhance the glucose-induced insulin release, they may contribute to the beneficial effects on maturation and growth caused by sensory stimulation. In the breast-feeding situation, the sucking of the child elicits similar reflexes in the mother leading to an activation of the maternal gut endocrine system and a consequent increase in energy uptake. These data indicate that many types of neurogenic reflexes induced in mother-infant interactions are of importance for the energy economy of both mother and child.  相似文献   
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