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   84篇
  免费   6篇
林业   6篇
农学   2篇
  12篇
综合类   10篇
农作物   6篇
水产渔业   4篇
畜牧兽医   45篇
园艺   4篇
植物保护   1篇
  2022年   1篇
  2021年   2篇
  2019年   3篇
  2018年   2篇
  2017年   4篇
  2016年   4篇
  2014年   1篇
  2013年   7篇
  2012年   10篇
  2011年   6篇
  2010年   8篇
  2009年   6篇
  2008年   2篇
  2007年   10篇
  2006年   5篇
  2005年   3篇
  2003年   2篇
  2002年   1篇
  2001年   2篇
  2000年   1篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1992年   2篇
  1991年   1篇
  1984年   2篇
  1965年   1篇
排序方式: 共有90条查询结果,搜索用时 15 毫秒
61.
This study was undertaken to examine the developmental capacity of reconstituted mouse embryos, and the influences of nucleus and cytoplasm on the development of these embryos following reciprocal pronuclear transplantation between in vitro 2-cell blocked and nonblocked embryos. Karyoplast containing pronuclei was transferred into the perivitelline space of the enucleated zygote and fused to cytoplasm with electrofusion. Maximum fusion rate was obtained when a field strength of 1.5 kV/cm was used. The fusion rates were high (86.2 +/- 3.2 to 90.6 +/- 2.0%) regardless of the strains of donor nucleus and recipient cytoplasm. Developmental rates of reconstituted embryos to the blastocyst stage, which were similar to that of the F1 (C57BL/6J x CBA) control were high when F1 embryos were used as the cytoplasm recipients (88.8 +/- 1.5 and 91.9 +/- 2.0%). When ICR embryos were used as the recipient cytoplasm, developmental rates were significantly reduced (71.5 +/- 2.9 and 54.1 +/- 3.2%), and affected by the source of nucleus. There were no significant differences in the cell number of embryos that developed to blastocysts and in the developmental rates to live young among the embryos reconstituted with different nuclei and cytoplasm, and the ICR control. The results of this study show that the development of reconstituted embryos is hardly affected by nuclear transplantation and electrofusion procedures. It is indicated that the recipient cytoplasm, rather than the donor nucleus, has the greater influence on the in vitro development of the reconstituted embryos to the blastocyst stage.  相似文献   
62.

Background  

The co-existing, sibling species Mus booduga and Mus terricolor show a difference in site-preference for burrows. The former build them in flat portion of the fields while the latter make burrows in earthen mounds raised for holding water in cultivated fields. In northern India which experiences great variation in climatic condition between summer and winter, M. booduga burrows have an average depth of 41 cm, as against 30 cm in southern India with less climatic fluctuation.  相似文献   
63.
Skin ulcers, scoliosis, and dropsy-like scale edema were observed in laboratory-maintained zebrafish. Affected fish had multifocal granulomas not only in internal organs such as the liver, intestine, genital organs, kidney, muscle, and spleen but also in the fin, epithelium, gills, and sclera of the eyes. Large numbers of acid-fast-rod-shaped bacteria were observed within the necrotic centers of well-demarcated, multifocal granulomas with Gram's stain and Ziehl-Neelson's stain. The size of the Mycobacterium spp. was 1-2 microm x 2-3 microm with a double-layered cell wall, based upon electron-microscopical features. Definitive diagnosis of these outbreaks was obtained by culture on selective media followed by PCR-restriction fragment length polymorphism analysis (PRA) of the rpoB gene for species identification. The amplified 360-bp products of the rpoB gene of mycobacteria isolated from zebrafish were digested with MspI restriction enzyme, which revealed unique band patterns matching those of Mycobacterium abscessus and Mycobacterium chelonae which are responsible for skin and soft tissue infection caused by rapidly growing mycobacteria in humans. This is the first documentation of the precise identification of zoonotic non-tuberculous mycobacteria isolated from laboratory-maintained zebrafish by the PRA of the rpoB gene; this study thus provides a great deal of useful epidemiological information and reduces the likelihood that epizootics will occur.  相似文献   
64.
A 17 kDa antimicrobial protein was isolated from growth medium containing the filamentous fungus Aspergillus oryzae by extracting the supernatants from the culture media, ion exchange chromatography on CM-sepharose, and C18 reverse-phase high-performance liquid chromatography. This antimicrobial protein, which we considered to be an extracellular antimicrobial protein from A. oryzae (exAP-AO17), possessed antimicrobial activity but lacked hemolytic activity. The exAP-AO17 protein strongly inhibited pathogenic microbial strains, including pathogenic fungi, Fusarium moniliform var. subglutinans and Colletotrichum coccodes, and showed antibacterial activity against bacteria, including E. coli O157 and Staphylococcus aureus. To confirm that the protein acts as a regulation factor for extracellular secretion, we examined growth under varying conditions of N sources, C sources, ions, ambient pH, and stress. Various culture conditions were found to induce characteristic changes in the expression of protein synthesis as analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Highly basic polypeptides were regulated by suppressing the ambient pH under acidic conditions and strongly induced under alkaline conditions, thus confirming that pH regulation is physiologically relevant. The expression of exAP-AO17 was upregulated by heat shock upon growth in the presence of NaCl. Automated Edman degradation showed that the N-terminal sequence of exAP-AO17 was NH 2-GLPGPAGAVGFAGKDQNM-. ExAP-AO17 showed partial sequence homology with a collagen belonging to the animal source. These results suggest that exAP-AO17 is an excellent candidate as a lead compound for the development of novel oral or other types of anti-infective agents.  相似文献   
65.
To investigate the physico‐chemical and sensory properties of striploin muscles, 90 Hanwoo carcasses (QG 1+) were randomly selected within six maturity levels (4 to 9 according to age in months). Results demonstrated that the protein contents at maturity levels 4 and 5 were significantly higher than 9. No significant difference in fat, moisture and collagen contents were found at different maturity levels (P > 0.05). The quantity of collagen type I and ratio of type I to III were observed at higher maturity levels; collagen type III showed significantly high levels (P > 0.05) at low maturity and decreased with increase in maturity levels. Warner‐Bratzler shear force (WBSF) was significantly lower in groups 4 to 6, whereas water holding capacity (WHC) was significantly higher than maturity level 8 and 9 groups (P < 0.05). There were no significant differences in cooking loss among the maturity level groups (P > 0.05). Color properties, L* values of striploin muscle from maturity level 4 were significantly different from level 9 (P < 0.05). Sensory evaluation at level 4‐6 groups had significantly higher tenderness and overall likeness scores than level 9 (P < 0.05). The maturity levels were significantly correlated with age, fat, protein content, WHC, WBSF, cooking loss, CIE L* values and sensory properties like tenderness, juiciness, flavor‐likeness and overall likeness.  相似文献   
66.
A three‐year‐old intact female Old English sheepdog was presented for evaluation of infertility. A uterine biopsy was performed during dioestrus, and the microscopic appearance was inconsistent with progesterone stimulation; the glands were sparse, simple and failed to show coiling, while the glandular epithelium was cuboidal instead of columnar. There was very little evidence of glandular activity. Due to the inappropriate appearance of the glands for the stage of the cycle, immunohistochemistry for progesterone receptors was performed. No progesterone receptor‐positive immunoreactivity was identified in the endometrial luminal epithelium, glandular epithelium or stroma. Weak intranuclear immunoreactivity was identified within the smooth muscle cells of the myometrium. The absence of progesterone receptors within the endometrial glands is the most likely explanation for the abnormal appearance of the endometrium and for this bitch's infertility. To our knowledge, this is the first report of endometrial progesterone receptor absence in a bitch.  相似文献   
67.
Human amniotic membrane-derived mesenchymal stem cells (hAM-MSCs) are capable of differentiating into several lineages and possess immunomodulatory properties. In this study, we investigated the soluble factor-mediated immunomodulatory effects of hAM-MSCs. Mitogen-induced peripheral blood mononuclear cell (PBMC) proliferation was suppressed by hAM-MSCs in a dose-dependent manner as well as hAM-MSC culture supernatant. Moreover, interferon-gamma and interleukin (IL)-17 production significantly decreased from PBMC, whereas IL-10 from PBMCs and transforming growth factor beta (TGF-β) production from hAM-MSCs significantly increased in co-cultures of hAM-MSCs and PBMCs. Production of several MSC factors, including hepatocyte growth factor (HGF), TGF-β, prostaglandin E2 (PGE2), and indoleamine 2, 3 dioxygenase (IDO), increased significantly in hAM-MSCs co-cultured with PBMCs. These results indicate that the immunomodulatory effects of hAM-MSCs may be associated with soluble factors (TGF-β, HGF, PGE2, and IDO), suggesting that hAM-MSCs may have potential clinical use in regenerative medicine.  相似文献   
68.
From black spots on winter mushroom (Flammulina velutipes), fluorescent bacteria were repeatedly isolated during surveys at places of production in the years 2009–2010 in Korea. From these lesions three bacterial strains (designated CHM13, CHM16, CHM17) were isolated which, following inoculation of mushroom stipes and caps, yielded characteristic black spots and sunken lesions, which developed into a severe black rot. Results of Gram stain and biochemical tests preliminarily identified these isolates as Pseudomonas tolaasii. This was confirmed by pathogenicity to winter mushroom, physiological and biochemical properties, analysis of the 16S rRNA and rpoB gene sequences, fatty acids profile, specific and sensitive PCR assays and, lipopeptide detection. This is the first report of the isolation of Pseudomonas tolaasii from cultivated winter mushroom in Korea.  相似文献   
69.
70.
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