全文获取类型
收费全文 | 63篇 |
免费 | 0篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 4篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 4篇 |
2012年 | 4篇 |
2011年 | 3篇 |
2010年 | 2篇 |
2009年 | 2篇 |
2007年 | 2篇 |
2005年 | 3篇 |
2003年 | 2篇 |
2002年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1995年 | 1篇 |
1991年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1977年 | 1篇 |
1971年 | 1篇 |
1970年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有63条查询结果,搜索用时 156 毫秒
21.
22.
Plasma Physics Reports - The results of experimental studies on the fabrication of preforms of high aperture numerical quartz fiberoptic light guides (with a high fluorine content (up to 7 wt %)... 相似文献
23.
An original behavioral test was used to study the effect of opioid substances on the thresholds of nociceptive responses to
pain stimuli—a series of electric impulses applied to nerve endings of the caudal fin—in the common carp (Cyprinus carpio). The substances tested included tramadol (μ-agonist of opioid receptors), DADLE (δ-agonist), and U-50488 (κ-agonist) injected
intramuscularly in concentrations 10–100 nmol/g of body weight. Raised thresholds of sensitivity to the pain stimulus were
observed in the studied fish 5 to 15 min after the injection. The degree of analgesia and the rate of its increase varied
depending on the dose. The total duration of analgesia was 40 to 90 min and depended on the concentration of the injected
substance. It was observed in some experiments that the analgesic effect of tramadol (the most efficient of the analgesics
used) could last longer than 4 h. The analgesic effect of opioids was not detected in experiments where they were applied
together with naloxone, an antagonist of opioids. Decreased motor response to pain stimuli after injections of analgesics
was not caused by the immobilization of the animal, because the tested fish individuals released into an aquarium demonstrated
normal swimming and their usual behavior. We concluded that the systems of opioid nociceptive regulation function similarly
in fish and land vertebrates. This regulation can play an important role in defense behavior and in other behaviors in fish. 相似文献
24.
Plasma Physics Reports - Modeling of the pulse-periodic high-pressure cesium discharge on the basis of the radiative gas dynamic equations is executed. Calculation results of radial profiles of the... 相似文献
25.
Kevin CR Kerr Sharon M Birks Mikhail V Kalyakin Yaroslav A Red'kin Eugeny A Koblik Paul DN Hebert 《Frontiers in zoology》2009,6(1):1-13
Background
Many fish species experience long periods of fasting in nature often associated with seasonal reductions in water temperature and prey availability or spawning migrations. During periods of nutrient restriction, changes in metabolism occur to provide cellular energy via catabolic processes. Muscle is particularly affected by prolonged fasting as myofibrillar proteins act as a major energy source. To investigate the mechanisms of metabolic reorganisation with fasting and refeeding in a saltwater stage of Atlantic salmon (Salmo salar L.) we analysed the expression of genes involved in myogenesis, growth signalling, lipid biosynthesis and myofibrillar protein degradation and synthesis pathways using qPCR.Results
Hierarchical clustering of gene expression data revealed three clusters. The first cluster comprised genes involved in lipid metabolism and triacylglycerol synthesis (ALDOB, DGAT1 and LPL) which had peak expression 3-14d after refeeding. The second cluster comprised ADIPOQ, MLC2, IGF-I and TALDO1, with peak expression 14-32d after refeeding. Cluster III contained genes strongly down regulated as an initial response to feeding and included the ubiquitin ligases MuRF1 and MAFbx, myogenic regulatory factors and some metabolic genes.Conclusion
Early responses to refeeding in fasted salmon included the synthesis of triacylglycerols and activation of the adipogenic differentiation program. Inhibition of MuRF1 and MAFbx respectively may result in decreased degradation and concomitant increased production of myofibrillar proteins. Both of these processes preceded any increase in expression of myogenic regulatory factors and IGF-I. These responses could be a necessary strategy for an animal adapted to long periods of food deprivation whereby energy reserves are replenished prior to the resumption of myogenesis. 相似文献26.
The dependence of the breeding success of the eagle owl on the population dynamics of rodents, which are a staple of its diet in Mordovia, was traced. At peak numbers of rodents, large clutches and a high survival rate of fledglings were observed in the breeding pairs; after a year of depression of rodent populations, in the following year, the pairs do not nest at all or their breeding success is reduced to a minimum due to the death of the clutches. In 52% of the cases, the nesting pairs laid three eggs; in 31%, two eggs; in 9%, four eggs; in 4%, one egg or five eggs. The average clutch size was 2.78 ± 0.17. The average number of chicks grown from a successful nest was 2.41 ± 0.27. The nests in Mordovia were located at a distance of 1.1–3.7 km from residential areas. 相似文献
27.
The pathways of fluorescent chromophores introduction into the cholesterol molecule are reviewed and physicochemical, optical properties and biological identity of fluorescent cholesterol derivatives (FCD) to the natural analogues are briefly characterized. Methods of the FCD incorporation into biological objects are discussed. The main part of the review is devoted to the use of FCD to investigate the model and biological membranes, blood plasma lipoproteins and their interactions with cells. The first attempts of the FCD application in the study of sterol-carrier proteins are discussed. 相似文献
28.
Biophysics - Numerous species of the genus Aloe have attracted the attention of researchers because of their different biological benefits and their capacity to act as antioxidants. This paper... 相似文献
29.
30.