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   52篇
  免费   3篇
林业   12篇
农学   4篇
  6篇
综合类   6篇
农作物   1篇
水产渔业   7篇
畜牧兽医   11篇
园艺   3篇
植物保护   5篇
  2023年   2篇
  2022年   1篇
  2020年   2篇
  2018年   2篇
  2017年   1篇
  2014年   2篇
  2013年   1篇
  2012年   3篇
  2011年   4篇
  2010年   2篇
  2009年   2篇
  2008年   1篇
  2006年   4篇
  2005年   4篇
  2004年   4篇
  2003年   1篇
  2002年   4篇
  2001年   4篇
  1999年   4篇
  1998年   1篇
  1995年   1篇
  1989年   1篇
  1988年   1篇
  1983年   1篇
  1982年   1篇
  1979年   1篇
排序方式: 共有55条查询结果,搜索用时 296 毫秒
21.
The storage of ripe tomatoes in low-O(2) conditions with and without CO(2) promotes γ-aminobutyric acid (GABA) accumulation. The activities of glutamate decarboxylase (GAD) and α-ketoglutarate-dependent GABA transaminase (GABA-TK) were higher and lower, respectively, following storage under hypoxic (2.4 or 3.5% O(2)) or adjusted aerobic (11% O(2)) conditions compared to the activities in air for 7 days at 25 °C. GAD activity was consistent with the expression level of mRNA for GAD. The GABA concentration in tomatoes stored under hypoxic conditions and adjusted aerobic conditions was 60-90% higher than that when they are stored in air on the same day. These results demonstrate that upregulation of GAD activity and downregulation of GABA-TK activity cause GABA accumulation in tomatoes stored under low-O(2) conditions. Meanwhile, the effect of CO(2) on GABA accumulation is probably minimal.  相似文献   
22.
Variations of the vascular bundle system in Asian rice cultivars   总被引:3,自引:0,他引:3  
Summary The capacity of vascular bundle system transporting assimilates from source to sink is one of the limiting factors for rice (Oryza sativa L.) yield. Genetic variation in vascular bundle system should be investigated for improvement of transporting efficiency. A total of 531 Asian rice cultivars were studied for vascular bundles in the peduncle and its relation to spike morphology. A few difference was detected for the number of primary rachis branches of the spike among the cultivars from various countries. However, the number of vascular bundles significantly differed among the cultivars; those from Nepal, Bangladesh and India bore more vascular bundles than those from Japan. Therefore, the ratio of vascular bundles to rachis branches (V/R ratio) was nearly 1.0 in cultivars from Japan, while those from Nepal, Bangladesh and India ranged from 1.3 to 2.2. Chinese and Indonesian cultivars incuded two types of high and low V/R ratios. Cultivars with high V/R ratio showed positive reactions to the phenol solution, while those with low V/R ratio were negative reactions, suggesting that the former cultivars are of Indica type and the latter of Japonica type. It was concluded that the relationship between vascular bundles and rachis branches differentiated among the ecotypes of Asian cultivated rice.  相似文献   
23.
A defect in Klotho gene expression in mice accelerates the degeneration of multiple age-sensitive traits. Here, we show that overexpression of Klotho in mice extends life span. Klotho protein functions as a circulating hormone that binds to a cell-surface receptor and represses intracellular signals of insulin and insulin-like growth factor 1 (IGF1), an evolutionarily conserved mechanism for extending life span. Alleviation of aging-like phenotypes in Klotho-deficient mice was observed by perturbing insulin and IGF1 signaling, suggesting that Klotho-mediated inhibition of insulin and IGF1 signaling contributes to its anti-aging properties. Klotho protein may function as an anti-aging hormone in mammals.  相似文献   
24.
Two cytologic variants of γδ T cell lymphoma are described. Case 1 represented a giant cell variant found in a 5-year-old Holstein cow, which had large tumor masses in the pelvic cavity. This variant consisted of very large lymphoid cells with round to oval nuclei, medium-sized nucleoli and abundant cytoplasm. Case 2 was an aborted 7-month-old female Holstein fetus, which represented an immature cell variant. Most of the neoplastic lesions were located in the skin and pleural and peritoneal submesothelial tissues. The neoplastic tissues were composed of homogeneous growth of lymphoma cells characterized by inconspicuous nucleoli and finely dispersed chromatin. Both cases demonstrated CD3, CD8 and WC1 immunoreactivity. The current study revealed that there are 4 cytologic variants (common, giant cell, hypergranular and immature cell) in bovine γδ T cell lymphomas.  相似文献   
25.
A mass propagation scheme for Lilium plants using a shake culture technique has been developed. According to the scheme, about 1.2 × 1010 of L. speciosum or 3.2 × 1012 of L. auratum bulbs can theoretically be obtained in one year from one medium sized bulb. The scheme involves 4 steps: (1) establishment of aseptic production of bulblets; (2) the stimulation of bulb-scale production by high K and their rapid growth in shake cultures; (3) bulblet production; (4) the establishment of bulblets in soil.  相似文献   
26.
Wood is generally used as the interior material in museum storage rooms. Recently, however, the effects of volatile organic compounds (VOCs) from wood on artifacts has become a topic of great concern. The VOCs from four species of wood (western red cedar, spruce, kiri, and sugi) and their effects on artifact materials (two types of metal, seven types of pigment) were investigated using a deterioration-accelerating test, gas chromatography-mass spectrometry, X-ray diffraction analysis, and X-ray photoelectron spectroscopy. The results suggested that the influences on artifact materials varied greatly with wood species, and depended on specific components such as hinokitiol or acetic acid rather than the amount of total volatile organic compounds (TVOCs). It is a very serious problem that of the four species of wood, western red cedar (rich in hinokitiol), which has been recommended as an interior material for museum storage rooms, showed the heaviest deterioration on metal samples, and only this type of wood discolored enpaku (white lead) and rokushou (malachite, verdigris). In such storage rooms, museum artifacts should be carefully monitored. When selecting an interior material for a storage room or studying methods of preventing deterioration, it is very important to consider fully the characteristics of wood VOCs, not only the amount of TVOC.Part of this paper was presented at the 24th (Tokyo, June 2002) and 25th (Kyoto, June 2003) Annual Meeting of the Japan Society for the Conservation of Cultural Property  相似文献   
27.
28.
The Japanese eight-barbel loach Lefua echigonia, which is a freshwater fish native to Japan, is distributed from the Tohoku to Kinki districts and is divided into six regional populations according to mtDNA analysis. In this study, we investigated L. echigonia collected from several locations in Yamagata Prefecture and neighboring prefectures using mtDNA control region sequences and confirmed the spatial distribution pattern among the new regional population (Yamagata population). The new population was limited to the Mogami river system in the inland area of Yamagata Prefecture and is distinguished from other regional populations by high sequence divergences.  相似文献   
29.
The excellent flavor of Wagyu is becoming increasingly popular all over the world. However, the popularity of Wagyu has encouraged competition for authentic Japanese Wagyu, resulting in the appearance of inauthentic Wagyu beef. To ward off this export competition, Japanese Wagyu producers need to improve and differentiate their value‐added beef. As hardly any past studies focus on the consumption of Japanese Wagyu in Hong Kong, this paper uses a choice experiment to examine the valuation of beef by Hong Kong consumers in terms of country of origin. Data from 250 Hong Kong consumers obtained through a web questionnaire were used to analyze the beef preferences. In addition to the beef's country of origin, its marbling level, the Japanese Wagyu label and reference point effects were considered. The results indicate that Hong Kong consumers place a significant premium on Japanese Wagyu over Australian or American Wagyu. That premium is greater among consumers who have seen the Japanese Wagyu label. Reference price effects were also statistically confirmed. To promote Japanese Wagyu beef consumption, therefore, it is important to make the consumer aware of the advantages of Japanese Wagyu.  相似文献   
30.
进行了臂形草内生菌特异DNA片段的克隆及分子鉴定方法的研究。从5个臂形草品种分离的5个内生菌纯培养特中,提取基因组DNA,通过140条随机引物的RAPD分析,引物OPAK10扩增出1条约500bp的共有PCR谱带。此DNA片段命名为BE1。对BE1进行分离、纯化,经点杂交证实BE1为臂形草内生菌特异DNA片段。进一步将BE1片段进行回收、克隆和DNA序列分析。BE1在基因库中进行序列分析,未发现相关同源片段。臂形草内生菌特异DNA片段的获得,为建立一种准确、快速检测臂形草内生菌及特异内生菌方法奠定了分子生物学基础。  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