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   86篇
  免费   0篇
基础科学   1篇
  9篇
综合类   5篇
水产渔业   2篇
畜牧兽医   59篇
植物保护   10篇
  2022年   10篇
  2021年   6篇
  2017年   1篇
  2016年   4篇
  2015年   9篇
  2014年   10篇
  2013年   7篇
  2012年   1篇
  2011年   3篇
  2010年   1篇
  2009年   4篇
  2008年   2篇
  2007年   3篇
  2006年   5篇
  2005年   2篇
  2003年   1篇
  2002年   6篇
  2001年   2篇
  2000年   3篇
  1993年   1篇
  1992年   1篇
  1990年   1篇
  1963年   1篇
  1959年   1篇
  1957年   1篇
排序方式: 共有86条查询结果,搜索用时 15 毫秒
61.
A cardiac mass (3 × 5 × 3 cm) was detected at the base between the right auricular wall and right vena cava of a slaughtered 6-month-old female mixed-breed pig during a meat inspection. The tumor comprised infiltrative prominent interweaving fascicles of Schwann cells with Verocay bodies. Moreover, the ganglion cells were scattered or aggregated throughout the neoplastic tissue. The ganglion and Schwann cells had neither cellular atypism nor mitosis. On the basis of the bearing site as well as the morphological and immunohistochemical features, this is the first case of a cardiac ganglioneuroma in a pig.  相似文献   
62.
pp. 881–889
In order to understand the influences of nitrogen and silicate fertilizer application on anther length and percentage of the sterility of the rice plant, we investigated by field experiment in Hokkaido Kamikawa Agric. Exp. Stn. (Brown Lowland soil) and by air-conditioned room experiment.
  The results are summarized as follows.
1) Application of silicate fertilizer decreased percentage of sterility. Compared with basal application, topdressing of silicate fertilizer was more effective in increasing carbohydrate content and anther length, decreasing percentage of sterility.
2) The anther length was negatively correlated to percentage of sterility and was positively correlated to carbohydrate content in the rice plant. Similar regression curves were plotted between the field experiment and the air-conditioned room experiment.
3) Silicate content in rice plants was increased at the flag leaf stage by applying both basal and topdressing silicate fertilizer. Furthermore, silicate content was correlated to carbohydrate content. Nitrogen content was negatively correlated to carbohydrate content.
4) Protein content in polished rice was decreased by silicate fertilizer application.  相似文献   
63.
64.
Puberty is associated with an increase in gonadotropin secretion as a result of an increase in gonadotropin-releasing hormone (GnRH) secretion. Kisspeptin is considered to play a key role in puberty onset in many mammalian species, including rodents, ruminants and primates. The present study aimed to determine if changes in hypothalamic expression of the KISS1 gene, encoding kisspeptin, are associated with the onset of puberty in pigs. The animals (n=4 in each group) were perfused with 4% paraformaldehyde at 0, 1, 2, 3 and 4 months old, as prepubertal stages, and at 5 months old, as the peripubertal stage, following each blood sampling. KISS1 gene expressions in coronal sections of brains were visualized by in situ hybridization. Plasma luteinizing hormone (LH) was measured by radioimmunoassay. KISS1 mRNA signals were observed in the arcuate nucleus (ARC) at all ages examined without any significant difference in the number of KISS1-expressing cells, indicating that the KISS1 gene is constantly expressed in the ARC throughout pubertal development in pigs. The plasma LH concentration was the highest in 0-month-old piglets and significantly decreased in the 1- and 2 month-old groups (P<0.05), suggesting a developing negative feedback mechanism affecting gonadotropin release during the prepubertal period. Considering the potent stimulating effect of kisspeptin on gonadotropin release in prepubertal pigs, kisspeptin secretion rather than kisspeptin synthesis may be responsible for the onset of puberty in pigs.  相似文献   
65.
66.
To analyze the regulation of hrp expression and to detect and identify hrp-dependent secretion proteins of plant-pathogenic bacteria, an appropriate hrp-inducing medium is indispensable. In this study, two efficient hrp-inducing media for Xanthomonas oryzae pv. oryzae were designed by assaying the expression of a hrcU (the first gene of the hrpC operon) and a gus (β-glucuronidase) fusion gene. We modified XVM2, which is a hrp-inducing medium for X. campestris pv. vesicatoria, by adding 0.01% xylose in place of fructose and sucrose (0.18 and 0.34%, respectively) as a sugar source. The resulting medium induced approximately 15-fold more GUS activity from transformants containing a hrcU::gus gene than did XVM2. Moreover, a methionine-containing synthetic medium with 0.18% xylose as a sugar source was able to induce much stronger expression of HrcU::GUS, with GUS activity approximately 100-fold greater than that in XVM2. Induction depended on a regulator, HrpXo, and the PIP (plant-inducible-promoter) box, suggesting that HrcU::GUS was expressed in a hrp-dependent manner. The induction of operons hrpA to hrpF in XOM2 was also confirmed. These results suggest that both media, especially XOM2, are highly efficient hrp-inducing media for X. oryzae pv. oryzae. Received 7 October 2002/ Accepted in revised form 22 November 2002  相似文献   
67.
The property of hydrophilic polymers capable absorbing huge volumes of water led to many practical applications of these new materials in arid regions for improving the water retention in sandy soils. Effects of four carboxymethylcelluloses (CMC), mixed at various rates with the sandy soil, on the water-holding capacity and hydraulic conductivity (KS ) when leached with distilled water (simulating rain), tap water, and saline water were evaluated. The maximum water absorption of CMCs ranged between 80 and 100 kg ? kg-1 of polymer; however, the absorbent swelling capacity decreased significantly with increasing the salt concentration in the solution. The water absorption capacity of CMCs decreased significantly when incorporated in the sandy soil compared to that of the absorbent alone. Application of CMC increased significantly the available water content up to 3 ± 0.5 times. All soils treated with CMCs showed a significant lower in KS compared to the control soil. Meanwhile, KS was found increased with increasing the salt concentration in the leaching solution. This understanding of characteristics of the absorbents and the interactions among absorbents, soil, and irrigation water quality would be of help in water management of sandy soil.  相似文献   
68.
The present study investigated severe fever with thrombocytopenia syndrome virus (SFTSV) infection in raccoons in Wakayama Prefecture from 2007 to 2019. To perform surveillance, an enzyme-linked immunosorbent assay (ELISA) was established, and the sensitivity and specificity of the ELISA were 100% in comparison with a 50% focus-reduction neutralization assay. Using the established ELISA, we performed serosurveillance of SFTSV infection in 2,299 raccoons in Tanabe region, Wakayama Prefecture from 2007 to 2019. The first anti-SFTSV-positive raccoon was captured in October 2009. The seroprevalence of SFTSV infection was <10% between April 2009 and March 2013, 23.9% between April 2013 and March 2014, 37.5% between April, 2014 and March 2015, and over 50% from April 2015. Next, we performed detection of SFTSV genes in sera of raccoons captured in Wakayama Prefecture after April 2013. The results indicated that 2.4% of raccoons were positive for SFTSV genes and that the frequency of SFTSV infection among raccoons between January and March (0.7%) was lower than that between April and June (3.4%). In addition, virus genes were detected from many specimens, including sera and feces of two raccoons, and viral antigens were detected in lymphoid cells in lymphoid follicles in the colon by immunohistochemical staining. In conclusion, SFTSV had recently invaded the area and had rapidly spread among wild animals. The first patient in this area was reported in June 2014, indicating that raccoons are good sentinels for assessing the risk of SFTSV in humans.  相似文献   
69.
The present study established techniques to induce pseudopregnancy, in vitro oocyte cultures from pronuclear to 2- to 4-cell stages, and embryo transfer in musk shrews, a reflex ovulator. Offspring were subsequently obtained by transferring in vivo-developed or in vitro-cultured embryos. Female musk shrews received human chronic gonadotropin (hCG), with or without mating stimuli, from vasectomized males to produce pseudopregnant recipients. Embryos at the 2- to 4-cell stage were collected 44–48 h after mating. Another set of embryos was collected 26–27 h after mating and then cultured for 20 h from the pronuclear to 2- to 4-cell stages. Subsequently, embryos were transferred into the oviducts of pseudopregnant recipients 24 or 48 h after the induction of pseudopregnancy. Offsprings were successfully obtained from recipients that received hCG 24 h before embryo transfer, regardless of mating stimuli. These techniques may be valuable for producing transgenic musk shrews.  相似文献   
70.
Previously, we classified Pseudomonas syringae strains into at least three groups (I, II and U) by comparing DNA homology at the hrp cluster and its neighboring regions (Inoue and Takikawa 1999). However, heterogeneous strains remained in the undetermined group (group U). We further classify group U, using pvs. syringae and coronafaciens as references. Comparison of restriction sites for regions of each pathovar revealed distinct differences. By using probes from the two pathovars, comparisons of DNA homology at the regions separated two additional distinct groups (III and IV) from group U. Therefore, P. syringae strains are classified into at least five groups. Received 4 November 1999/ Accepted in revised form 27 January 2000  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