首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   51篇
  免费   3篇
  国内免费   7篇
  2023年   1篇
  2022年   1篇
  2021年   2篇
  2020年   2篇
  2019年   2篇
  2018年   4篇
  2017年   2篇
  2015年   3篇
  2014年   3篇
  2013年   5篇
  2012年   1篇
  2011年   1篇
  2010年   2篇
  2009年   2篇
  2008年   1篇
  2007年   3篇
  2006年   2篇
  2003年   3篇
  2002年   1篇
  2001年   2篇
  2000年   1篇
  1998年   1篇
  1997年   3篇
  1995年   1篇
  1991年   1篇
  1990年   3篇
  1988年   1篇
  1987年   2篇
  1984年   3篇
  1979年   1篇
  1971年   1篇
排序方式: 共有61条查询结果,搜索用时 687 毫秒
11.
Since Korean mistletoe (Viscum album) has been used for alleviating metabolic diseases, it may also prevent the impairment of energy, glucose, lipid, and bone metabolisms in an estrogen-deficient animal model. We determined that long-term consumption of Korean mistletoe water extract (KME) can alleviate menopausal symptoms such as hot flush, increased abdominal fat mass, dyslipidemia, hyperglycemia, and decreased bone mineral density in ovariectomized (OVX) rats fed a high-fat diet, and explored the mechanisms of the effects. OVX rats were divided into four groups and fed high-fat diets supplemented with either 0.6% dextrin (control), 0.2% lyophilized KME + 0.4% dextrin (KME-L), or 0.6% lyophilized KME (KME-H). Sham rats were fed with the high-fat diets with 0.6% dextrin as a normal-control without estrogen deficiency. After eight weeks, OVX rats exhibited impaired energy, glucose and lipid metabolism, and decreased uterine and bone masses. KME-L did not alleviate energy dysfunction. However, KME-H lowered serum levels of total-, LDL-cholesterol, and triglycerides and elevated serum HDL-cholesterol levels in OVX rats with dyslipidemia, to similar levels as normal-control rats. Furthermore, KME-H improved HOMA-IR, an indicator of insulin resistance, in OVX rats. Surprisingly, KME-H fed rats had greater lean mass in the abdomen and leg without differences in fat mass but neither dosage of KME altered bone mineral density in the lumbar spine and femur. The increased lean mass was related to greater phosphorylation of mTOR and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) in the quadriceps muscles. Hepatic triglyceride contents were lowered with KME-H in OVX rats by increasing carnitine palmitoyltransferase-1 (CPT-1) expression and decreasing fatty acid synthase (FAS) and sterol regulatory element-binding protein-1c (SREBP-1c) expression. In conclusion, KME may be useful for preventing some menopausal symptoms such as hot flushes, dyslipidemia, hepatic steatosis, and loss of muscle mass in post-menopausal women.  相似文献   
12.
Soil-buried seeds of barnyardgrass ( Echinochloa crus-galli var. crus-galli ) germinated from April to June in three intermittent flushes. The later two flushes of germination occurred after heavy rainfall. Carbon dioxide concentration in soil air transiently increased to 30 dm3 m–3 after the rainfall, probably due to the increase in soil temperature and water potential. Germination of exhumed seeds was stimulated by exposure to CO2 at 30 dm3 m–3. Fluctuating temperature, light, water, ethylene, and nitrate are known to promote seed germination in many species. However, of these environmental factors, within ranges found in the field, only CO2 was effective in enhancing the germination of barnyardgrass seeds. We conclude that soil CO2 is responsible for causing intermittent flushes of germination. Detection of vegetation gaps may be explained by the responsiveness of buried seeds to CO2.  相似文献   
13.
It is generally known that the effect of the periodic boundary conditions using cubic boxes manifests itself as the underestimation for the self-diffusion coefficient and the difference between the experimental value and the simulation is proportional to the reciprocal of system size. Rather than the cubic boxes, the effect of the rectangular boxes, which has been normally ignored, however, exhibits some distinct features, according to the hydrodynamics theory on molecular diffusion. In particular, the diffusion coefficient along the direction of the short side length of the box is always larger than that along the larger side length. What’s unusual is that some components or even all three components of the diffusion coefficient may exceed that of an infinite system. Through the comparisons of the flow patterns excited by the diffusing particles, we find that the positive and negative corrections are linked to the local and global vortex of fluid, respectively. It appears that the box shape affects the diffusion by modifying the flow pattern. The theoretical predictions are further tested by molecular dynamics simulations.  相似文献   
14.
15.
Using periodic boundary conditions and external electric potential field, we have simulated an ion current flow through a flexible nanopore using cations and an explicit extended simple point charge (SPC/E) water with molecular dynamics simulation. The simulation voltages range goes beyond the usual ionic channel measurements ( ± 1 V) and yields useful information about density profiles, current density distribution and current–voltage (IV) characteristics.  相似文献   
16.
洗胃法与剖胃法在四种蛙食性分析中的对比   总被引:1,自引:0,他引:1  
在动物的食性研究中,剖胃法因要杀死动物,会产生一系列的生态学影响和伦理学问题,在国际上招致了越来越多的反对,而在我国仍广泛使用。尽管洗胃法已用于食性研究,它的效果却从来没有研究过。我们应用洗胃法研究了浙江宁波郭巨镇四种蛙(黑斑蛙、泽蛙、金线蛙和中华蟾蜍)的食性,并与剖胃法所获得的食性结果进行比较。结果显示:尽管洗胃法在四种蛙胃内食物量的总洗出率(在94.50%以上)和食物个体数的洗出率上(均大于93.46%)略低于剖胃法,但胃内未洗出的与洗出的平均食物个体大小间无差异(所有P>0.3061),两种方法获得的四种蛙的平均食物量和食物个体数也无差异(对食物量所有P>0.8680,对食物个体数所有P>0.7923)。结果表明,洗胃法是比较精确的,在动物的食性研究中,应广泛地推广洗胃法,摒弃剖胃法  相似文献   
17.
The reliability of three methods (microbial C and mineral-N flush by fumigation-incubation, and ATP) for measuring soil microbial biomass was assessed on two silt-loam soils of different P fertility status under grazed perennial pastures. The mineral-N flush and ATP methods provided a reasonably reliable index of microbial biomass, but the fumigation-incubation procedure for CO2-C flush, using preincubated samples and an unfumigated 0–10 day control, was inappropriate for these soils. The numbers of bacteria (direct microscopy) and the percentage metabolically active were also measured. Generally, in both soils, total microbial biomass and the numbers, mass and metabolic activity of bacteria were influenced more by temporal factors in samples taken monthly than by the fertility status. Temporal fluctuations were greater in the high-fertility (Waikanae) soil, but no consistent seasonal trends in mineral-N flush and ATP values were apparent. In both soils, numbers and biomass of bacteria were at a minimum in spring. Values of two biomass indices (mineral-N flush and ATP contents) were similar in the high- and low-fertility (Pomare) soil, and comprised similar percentages of organic-matter contents. The percentages of metabolically active bacteria, however, tended to be higher in Pomare than in Waikanae soil, and, therefore, did not reflect soil fertility status. Methodological and field aspects of these results are discussed.  相似文献   
18.
A set of independent N(O, ρ2) recursive residuals is obtained for a model proposed by GLEESON and McGILCHRIST (1980) to describe spatial dependence among observations on a rectangular lattice. These residuals can be used to test model adequacy in a similar fashion to Box-Jenkins techniques for time series models.  相似文献   
19.
The objective of this study was to compare the concentrations of inflammatory cytokines in uterine flush and serum from healthy postpartum dairy cows and cows with clinical or subclinical endometritis. Clinical endometritis was diagnosed by observation of vaginal discharges (>50% pus) and subclinical endometritis was diagnosed by evaluation of uterine cytology (neutrophils >18%) at 4 weeks postpartum. Uterine flush was obtained from 48 cows at 4, 6, and 8 weeks postpartum for evaluation of tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, IL-8, and IL-10 concentrations. Serum samples were obtained from 34 cows just after calving and at 1, 2, 4, 6, and 8 weeks postpartum for evaluation of TNF-α, IL-1β, and IL-6 concentrations. Concentrations of TNF-α, IL-6, and IL-10 were greater (P < 0.05) in cows with clinical endometritis than in cows with subclinical endometritis and healthy controls, whereas concentrations of IL-8 in both cows with clinical and subclinical endometritis were greater (P < 0.005) than in controls. Overall, IL-6 and IL-10 concentrations decreased during the postpartum period. IL-1β concentrations in cows with clinical endometritis decreased (P < 0.0005) during the postpartum, whereas concentrations in cows with subclinical endometritis and controls did not change significantly with time; at 4 weeks postpartum, concentrations were greater (P < 0.0001) in cows with clinical endometritis. There were no significant effects of group, sampling time, or interaction on serum cytokine concentrations. In conclusion, cows with endometritis have greater inflammatory cytokine concentrations in uterine flush than healthy cows, but no differences were observed in serum.  相似文献   
20.
BACKGROUND AND AIMS: Plants have the ability to compensate for damage caused by herbivores. This is important to plant growth, because a plant cannot always avoid damage, even if it has developed defence mechanisms against herbivores. In previous work, we elucidated the herbivory-induced compensatory response of Quercus (at both the individual shoot and whole sapling levels) in both low- and high-nutrient conditions throughout one growing season. In this study, we determine how the compensatory growth of Quercus serrata saplings is achieved at different nutrient levels. METHODS: Quercus serrata saplings were grown under controlled conditions. Length, number of leaves and percentage of leaf area lost on all extension units (EUs) were measured. KEY RESULTS: Both the probability of flushing and the length of subsequent EUs significantly increased with an increase in the length of the parent EU. The probability of flushing increased with an increase in leaf damage of the parent EU, but the length of subsequent EUs decreased. This indicates that EU growth is fundamentally regulated at the individual EU level. The probabilities of a second and third flush were significantly higher in plants in high-nutrient soil than those in low-nutrient soil. The subsequent EUs of damaged saplings were also significantly longer at high-nutrient conditions. CONCLUSIONS: An increase in the probability of flushes in response to herbivore damage is important for damaged saplings to produce new EUs; further, shortening the length of EUs helps to effectively reproduce foliage lost by herbivory. The probability of flushing also varied according to soil nutrient levels, suggesting that the compensatory growth of individual EUs in response to local damage levels is affected by the nutrients available to the whole sapling.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号