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   89篇
  免费   3篇
林业   10篇
农学   2篇
  11篇
综合类   6篇
农作物   5篇
水产渔业   13篇
畜牧兽医   36篇
园艺   1篇
植物保护   8篇
  2022年   2篇
  2021年   4篇
  2020年   2篇
  2018年   3篇
  2017年   2篇
  2016年   3篇
  2015年   3篇
  2014年   7篇
  2013年   3篇
  2012年   3篇
  2011年   12篇
  2010年   2篇
  2009年   2篇
  2008年   5篇
  2007年   5篇
  2006年   6篇
  2005年   2篇
  2004年   6篇
  2003年   3篇
  2002年   7篇
  2001年   5篇
  2000年   1篇
  1999年   2篇
  1997年   1篇
  1979年   1篇
排序方式: 共有92条查询结果,搜索用时 15 毫秒
51.
Anthocyanin synthesis began in the skin of ‘Olympia’ (Vitis labruscana Bailey) grape when the berry growth reached a late stage in the second sigmoid growth-curve. During berry development, shikimate NADP oxidoreductase (SORase, EC.1.1.1.25), phenylalanine ammonia-lyase (PAL, EC.4.3.1.5), and chalcone flavanone isomerase (CHFI, EC.5.5.1.6) were investigated in the skin. These enzyme activities were high during early development of the young berry, but rapidly decreased thereafter, and were activated again when rapid anthocyanin synthesis subsequently occurred. When PAL from the young berry was analyzed by isoelectricfocusing polyacrylamide gel electrophoresis (IEF-PAGE), it showed a single activity band with a pI value of approximately 5.4, whereas PAL from the ripe berry showed two activity bands with pIs of 5.4 and 6.5. Thus, SORase, PAL, and CHFI seem to be involved in anthocyanin accumulation simultaneously, and newly synthesized isozyme of PAL may play a key role in pigment formation in ‘Olympia’ skin. The function of these enzyme activities in young berry is also discussed in this text.  相似文献   
52.
53.
The double-chambered right ventricle (DCRV) is a rare congenital cardiac disease in dogs, and its detailed epidemiological and morphological features are not clearly understood. By investigating the profile, clinical signs, and characteristics of examination findings of eleven dogs with DCRV by means of a retrospective study, we attempted to clarify the epidemiology and morphology of the condition. The study group consisted of nine males and two females. Breeds included Pug (n=3), Miniature Dachshund (n=1), French Bull-dog (n=1), Shiba (n=1), and Retrievers (n=5). The attachment site of the anomalous muscular bundle was continuous with the cardiac apex in nine dogs, and it was attached to the right ventricle free wall in the other two dogs. In dogs with DCRV, at least one of the following conditions was present concurrently: congenital or acquired tricuspid valve regurgitation (TR), ventricular septal defect, and atrial septal defect. Also, the pressure difference between the two chambers increased over time, and progressive right-sided heart failure was observed. In summary, DCRV occurs in small breeds of dog as well as in large breeds of dog and it may be more prevalent in males. The existence of two types of DCRV in dogs was established. Dog with DCRVs will have a high incidence of concurrent cardiac abnormalities. Concurrent TR may be either congenital or acquired. DCRV is a congenital disorder, but the clinical condition progresses as the dog develops.  相似文献   
54.
We previously reported that growth hormone (GH) pulses were negatively associated with neuropeptide Y (NPY) profiles in cerebrospinal fluid (CSF) of the third ventricle of Shiba goats. In addition, while most GH pulses were coincident with GH-releasing hormone (GHRH) pulses, there was no correlation between GH and somatostatin (SRIF) levels. The present study was performed to elucidate the relationship between GH pulses and these neuropeptide levels in CSF when estradiol (1.0 mg/head) was subcutaneously administered to ovariectomized goats. CSF and plasma samples were collected every 15 min for 18 h (from 6 h before to 12 h after injection). GH levels in peripheral blood and GHRH, SRIF and NPY levels in CSF were measured by radioimmunoassay. Pulse/trough characteristics and correlations were assessed by the ULTRA algorithm and cross-correlation analysis. Before estradiol was injected, significant coincidence was found between GHRH pulses and GH pulses, and negative coincidence was found between NPY troughs and GH pulses. Six to 12 h after estradiol injection, the amplitude and area under the curve (AUC) of the GH pulses were markedly increased. The duration and AUC of the GHRH pulses in the CSF were also increased, and stronger synchrony of GHRH with GH was observed. In contrast, the baseline of NPY was significantly decreased, and the negative correlation between the GH pulses and NPY troughs disappeared. The parameters of SRIF troughs were not clearly changed. These observations suggest that estrogen enhances the pattern of secretion of GH in the goat via enhancement of GHRH pulses and decrease of NPY levels.  相似文献   
55.
In dairy cows, retained fetal membranes (RFM) affect reproductive performance. The aim of this study was to examine the leukocyte counts and the gene expression of tumour necrosis factor α (TNFα), interleukin 1β (IL‐1β), IL‐8, and IL‐10 in polymorphonuclear leukocytes (PMNs) and peripheral blood mononuclear cells (PBMCs) in cows with (n = 5) or without (n = 5) RFM during the peripartum period. The lymphocyte counts in RFM cows were higher than those in control cows throughout the experiment (p < .05). The expression of IL‐8 in PMNs of control cows was higher (p < .05) compared with that of RFM cows postpartum. In cows with RFM, IL‐1β expression was higher (p < .05) in PMNs at 6 weeks postpartum whereas the expression of IL‐1β was lower (p < .05) in PBMCs at 4 weeks postpartum. The expression of IL‐10 in PBMCs of control cows was higher (p < .05) than that of RFM cows at 2 weeks prepartum and 4 weeks postpartum. Taken together, our data indicate that changes of gene expression of pro‐ and anti‐inflammatory cytokines in RFM cows might be associated with the delayed placental separation and development of uterine inflammation in RFM cows.  相似文献   
56.
57.
Arabesque greenling Pleurogrammus azonus form schools of 30,000–60,000 individuals to feed on mesozooplankton near the sea surface. The fish need to be close to the surface where mesozooplankton production occurs, but the food is not sufficiently dense there for the fish to grow optimally while avoiding predation by sea birds. Arabesque greenling use a unique method to optimize their feeding conditions while avoiding staying on the sea surface. When the school swims upward, water is pushed downward. Upward swimming of a school of 30,000 individuals generates a downward stream of about 0.8–1.1 m/s, resulting in a convergent flow near the surface. This convergence concentrates the mesozooplankton on the sea surface and transports them into deeper layers with a strong vortex about 3.0 m in diameter and 10–20 m long. Thus, schooling of this fish induces vortex flows that provide a rich feeding environment.  相似文献   
58.
To survey endophytic actinomycetes as potential biocontrol agents against fungal diseases of rhododendron, young plants of rhododendron were surface-sterilized for use as an isolation source. Nine, six and two isolates, with distinguishing characteristics based on the macroscopic appearance of colonies, were obtained from roots, stems and leaves, respectively, suggesting that various species of actinomycetes grow in the respective organs of this plant as symbionts or parasites. On an agar medium, only isolate R-5 commonly formed a clear growth-inhibition zone against two major fungal pathogens of rhododendron, Phytophthora cinnamomi and Pestalotiopsis sydowiana, indicating that this isolate can produce antifungal material(s). Acetone extracts of a liquid culture of R-5 had a broad antimicrobial spectrum against Gram-positive bacteria, yeast and filamentous fungi. Isolate R-5 was identified as a Streptomyces sp. based on morphological, physiological and chemotaxonomical characteristics. The present results indicate that isolate R-5 is a suitable candidate for the biocontrol of diseases of rhododendron. Received 25 March 2000/ Accepted in revised form 18 May 2000  相似文献   
59.
60.
To investigate the relationships between trace elements concentrations in hair and atrial fibrillation (AF) in horses, concentrations of nineteen trace elements were detected in hair using the particle induced X-ray emission (PIXE) method. The horses were assigned to either control (n=22, no abnormalities) or AF groups (n=5) based on electrocardiograph findings. The mean concentrations of Ca and Zn in the hair of the AF group were significantly higher than those in the control group. The Zn/Cu ratio of the hair in the AF group (29.8 +/- 5.5) was significantly higher than that in the control group (23.4 +/- 2.2, P<0.05). The results of the present study suggest that there is a relationship between elevated concentrations of Ca and Zn in hair and AF.  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