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   32篇
  免费   1篇
林业   2篇
  10篇
综合类   2篇
农作物   4篇
水产渔业   4篇
畜牧兽医   9篇
植物保护   2篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2017年   2篇
  2016年   2篇
  2015年   1篇
  2014年   3篇
  2013年   2篇
  2012年   3篇
  2009年   3篇
  2008年   3篇
  2007年   1篇
  2006年   2篇
  2004年   1篇
  2003年   3篇
  2002年   1篇
  2000年   1篇
  1997年   1篇
  1981年   1篇
排序方式: 共有33条查询结果,搜索用时 31 毫秒
11.
Preclinical or clinical trials for muscular dystrophies have met with modest success, mainly because of inefficient delivery of viral vectors or donor cells to dystrophic muscles. We report here that intra-arterial delivery of wild-type mesoangioblasts, a class of vessel-associated stem cells, corrects morphologically and functionally the dystrophic phenotype of virtually all downstream muscles in adult immunocompetent alpha-sarcoglycan (alpha-SG) null mice, a model organism for limb-girdle muscular dystrophy. When mesoangioblasts isolated from juvenile dystrophic mice and transduced with a lentiviral vector expressing alpha-SG were injected into the femoral artery of dystrophic mice, they reconstituted skeletal muscle in a manner similar to that seen in wild-type cells. The success of this protocol was mainly due to widespread distribution of donor stem cells through the capillary network, a distinct advantage of this strategy over previous approaches.  相似文献   
12.
Heat shock proteins play a crucial role in cellular development, proliferation, differentiation and apoptosis. Heat shock protein 90 (HSP90) has been localised in the human endometrium, where its immunoexpression changes during the menstrual cycle. Similar studies have not been done for the equid species, so the present study aimed to describe endometrial HSP90 immunoexpression in mare endometrium. Endometrial biopsies were formalin-fixed and paraffin-embedded, and sections were stained with haematoxylin–eosin in preparation for HSP90 immunohistochemistry. Immunostaining and morphometric analyses were performed on the epithelial lining, endometrial glands and connective stroma during oestrus, dioestrus phase and anoestrus period (n = 7 per phase or period). Immunoexpression was localised in the basal region of the epithelial cells lining the lumen. Immunoexpression was greater during oestrus than during either dioestrus or anoestrus. During anoestrus, there was little immunostaining in the endometrium, suggesting that HSP90 is involved in the functional modulation of sex steroid receptors in cyclic mares. Indeed, the function of HSP90 as a chaperone in the folding of proteins, such as steroid receptors, might explain the greater intensity of immunostaining during the oestrus and dioestrus phases, compared the anoestrus period. We conclude that, in the mare, HSP90 plays a role in endometrial function and that further studies are needed to test whether it is important in pathological conditions as endometritis.  相似文献   
13.
  1. In the south‐eastern Pacific Ocean, few studies of whale sharks (Rhincodon typus) exist. In Peru, the northern coast has been identified as the area with the highest presence of whale sharks, yet their ecology in this area is poorly defined.
  2. This study predicts the spatial distribution of whale sharks off coastal northern Peru (03°00′S–04°30′S) during La Niña and El Niño seasonal conditions, utilizing maximum entropy modelling. Between 2009 and 2018 (except for 2011), 347 whale sharks were geo‐referenced in northern Peru with greatest data recordings in the austral summer and spring during La Niña events.
  3. Depth was the most important predictive variable for spatial distribution of whale sharks, followed by chlorophyll‐a. Sharks were predicted in shallower coastal waters in which chlorophyll‐a values are higher.
  4. Habitat suitability was higher in the northern coastal part of the study area. Spring presents the most suitable environmental conditions for whale sharks, both during La Niña and El Niño conditions. The probability of whale shark presence in the north of Peru increases at higher chlorophyll‐a and sea surface temperature values. Therefore, whale sharks appear to aggregate seasonally in northern Peru, potentially exploiting rich foraging grounds.
  5. In these areas of high suitability, whale sharks are susceptible to fisheries, bycatch, ship collisions, unmanaged tourism, and pollution; thus, management actions should focus in these areas.
  6. This study represents a first step to understand the distribution and habitat suitability of whale shark in Peruvian waters. Further studies should identify suitable habitat for whale sharks in offshore areas. Also, these should focus on the connectivity of these aggregations with other localities in the south‐eastern Pacific in order to contribute to regional strategies for the conservation of this iconic species in this particular region.
  相似文献   
14.
Various studies have been carried out on wheat flour to understand protein and starch changes when subjected to mixing and temperature constraints, but structural changes of proteins and starch at the typical moisture levels of a dough system are not fully understood. The aim of this research was to improve our understanding of (micro)structural changes at the mesoscopic level, through empirical rheology, microscopy (light and scanning electron microscopy), sequential protein extractions, and glutenin macropolymer wet weight along the mixing, heating, and cooling stages of the Mixolab assay. Studies were performed on three wheat flours with different protein contents. The rheological analysis allowed identifying the role of the proteins and the relationship between the protein content and different primary and secondary parameters obtained from the recorded curves. The progressive heating and mixing stages during the Mixolab assay resulted in a dynamic de‐ and restructuring of proteins involving interactions between the flour proteins from water soluble to SDS soluble to SDS insoluble and vice versa. The microstructure analysis with light, polarized, and scanning electron microscopy revealed the changes that proteins and starch molecules underwent during mixing, heating, and cooling. Qualitatively, the starch structural changes, swelling, and gelatinization observed by microscopic techniques showed some parallels with protein (and glutenin) content of the respective flour. Nevertheless, this tentative finding needs further confirmation by studying flour samples with large differences in glutenin content.  相似文献   
15.
In the absence of breeding strategy, natural spawning constitutes the breeding ground for fish farmers to empirically manage their commercial broodstock. In this context, we used six microsatellite markers to characterize the genetic pattern of six commercial seabream broodfish tanks having a common history spanning four generations. The progeny of one tank single‐day mass‐spawning event, reared in two different environments, was used to estimate the genetic parameters for body weight. Limited genetic differentiation was observed among broodfish groups. A panel of nine loci allowed us to unambiguously assign 95.4% of the offspring (1692) and identify 37 parents (65% of the total broodfish). The limited effective population size (Ne = 15.3) was due to the elevated variance of parental contributions and to broodfish failing to contribute to the progeny. The fluctuation of the allele frequency highlighted the risks of genetic drift and reduction in the heterozygosity in the next generations. Heritability for body weight was moderate at commercial size (0.40 ± 0.10) and the high genetic correlation at later stages laid the groundwork for precocious selection criteria for growth. The discussion opens on the opportunity to use mass spawning for selective breeding.  相似文献   
16.
To analyze the relationship between the management of three forest stand plantations and soil quality in the Dimapur district of the Northeastern Himalayan region,India,three forest soil profiles,covered by different species stands,at three depths were tested for 13 physical and chemical variables.Only four of these variables(electric conductivity,bulk density exchangeable Mg and available P)were included in a minimum data set,after using a varimax rotation algorithm in a principal component analysis,and subsequently used to calculate a soil quality index(SQI).Results showed higher SQIs in the surface layers(0–20 cm depth)than in the deeper ones.Average weighed SQI varied significantly(P<0.05)through the three considered forest sites,with the lowest value at site FS3.These findings reveal that the approach used here is suitable for preliminary screening of the impact of a forestry species on soil,to aid in species selection and improve soil health for afforestation and reforestation projects.  相似文献   
17.
The increasing incidence of candidiasis has drawn the attention of scientists and clinicians attempting to improve methods of studying Candida yeasts. PCR amplification followed by agarose gel electrophoresis (PCR-AGE) and the manual method (morphological characteristics, biochemical profiles and culturing on CHROMagar-Candida) and VITEK 2 automated method were used to test a total of 30 fungal strains from dog sources. The strains were obtained from cases of dermatitis, otitis externa and from the ears, oral mucosa, vaginal mucosa, prepuce and perianal region of clinically normal dogs. After identification as Candida yeasts by the manual method, the strains were analyzed using both VITEK and PCR-AGE methods. Isolates of C. parapsilosis ATCC 22019, C. krusei ATCC 6258 and C. albicans ATCC 10231 were included as controls. The universal primers ITS1, ITS3 and ITS4 were used in two independent PCR reactions. Of 30 yeast isolates, 3 isolates (Saccharomyces cerevisiae, C. rugosa and C. parapsilosis) that were incompletely identified by the manual method were identified with the PCR-AGE and VITEK methods. The results revealed a 96.7% and 86.7% concurrent identification between the PCR-AGE and VITEK methods versus the manual method, respectively. PCR-AGE showed a greater level of concordance with the manual method, besides being faster and more sensitive than the other methods examined, and is therefore indicated for routine diagnostic testing of Candida spp. strains from veterinary sources.  相似文献   
18.
19.
20.
The average content of some classes of antioxidants is generally higher in cherry tomatoes than in normal-sized berries. The aim of this work was to assess the nutritional value of cherry tomato (cv. Naomi F1) by investigating the compositional pattern of berries harvested at different ripening stages and evaluating, in particular, all of the main antioxidants (carotenoids, ascorbic acid, phenolic compounds, and alpha-tocopherol) and the antioxidant activity of the water-soluble and water-insoluble fractions. Results confirmed the relatively high level of carotenoids in cherry tomato but showed that not all biologically active compounds necessarily increase in tomatoes picked at later stages of ripeness. Cherry tomatoes harvested at full ripeness exhibited the highest level of carotenoids and antioxidant activity in the water-insoluble fraction. On the other hand, no significant differences in ascorbic acid content were observed at different ripening stages, whereas the main phenolics content and the antioxidant activity of water-soluble fraction showed slight, but significant, decreases at later stages of ripeness.  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