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   189篇
  免费   1篇
  国内免费   1篇
林业   4篇
农学   9篇
  26篇
综合类   4篇
农作物   7篇
水产渔业   11篇
畜牧兽医   110篇
植物保护   20篇
  2022年   9篇
  2021年   13篇
  2020年   3篇
  2019年   1篇
  2018年   3篇
  2017年   1篇
  2016年   3篇
  2015年   21篇
  2014年   14篇
  2013年   12篇
  2012年   8篇
  2011年   7篇
  2010年   3篇
  2009年   9篇
  2008年   8篇
  2007年   6篇
  2006年   15篇
  2005年   9篇
  2004年   8篇
  2003年   10篇
  2002年   12篇
  2001年   2篇
  2000年   7篇
  1999年   1篇
  1998年   3篇
  1996年   1篇
  1990年   1篇
  1961年   1篇
排序方式: 共有191条查询结果,搜索用时 15 毫秒
111.
112.
113.
Marine bacteria have not been examined as extensively as land bacteria. We screened carotenoids from orange or red pigments-producing marine bacteria belonging to rare or novel species. The new acyclic carotenoids with a C30 aglycone, diapolycopenedioc acid xylosylesters A–C and methyl 5-glucosyl-5,6-dihydro-apo-4,4′-lycopenoate, were isolated from the novel Gram-negative bacterium Rubritalea squalenifaciens, which belongs to phylum Verrucomicrobia, as well as the low-GC Gram-positive bacterium Planococcus maritimus strain iso-3 belonging to the class Bacilli, phylum Firmicutes, respectively. The rare monocyclic C40 carotenoids, (3R)-saproxanthin and (3R,2′S)-myxol, were isolated from novel species of Gram-negative bacteria belonging to the family Flavobacteriaceae, phylum Bacteroidetes. In this review, we report the structures and antioxidant activities of these carotenoids, and consider relationships between bacterial phyla and carotenoid structures.  相似文献   
114.
ABSTRACT: Nucleoplasmin, first isolated from Xenopus laevis eggs, promotes nucleosome assembly. Hereby, we have purified a nucleoplasmin-like protein from carp ( Cyprinus carpio ) eggs using ion exchange and subsequent gel filtration columns. The protein was recognized by a polyclonal antiserum against Xenopus laevis nucleoplasmin and had an amino acid composition similar to other member of the nucleoplasmin family proteins. Partial amino acid sequences from the cyanogen bromide (CNBr)-cleaved fragments showed high homology with Xenopus nucleoplasmin. The protein was also found to form an oligomeric complex and to be phosphorylated. Moreover, this protein promoted sperm nuclear decondensation as well as that of nucleoplasmin from Xenopus laevis eggs. These results suggest that the fish protein isolated here is a member of nucleoplasmin family.  相似文献   
115.
最近,一株无毒力的新城疫病毒(NDV)在鸡体内繁殖时,变成了强毒株,但致今尚未能证实,经鸡体传代的野生水禽新城疫病毒是否也具有变成速发型毒株的能力,为了通过实验证明从水禽中分离的非致病型NDV可以转变为速发型病毒,我们通过在鸡体内传播鹅源性无毒力株,经气囊接种连续传代9次,随后再在鸡脑内传代5次,结果显示,该病毒的毒力变得很强,致死率可达100%,通过致病性试验证实,其具有典型的速发型病毒特征;融合蛋白裂解位点的序列分析表明,原始的分离株含有无毒力型毒株共有的裂解序列;E-R-Q-E-R/L,而通过鸡体反复传代后,该序列变为致癞 性毒株共有的序列:K-R-Q-K-R/F,这些结果表明,野生水禽中自然存在的无毒力毒株,具有无毒力株相应的序列,但当其在鸡群中传播时,则具有变成高致病性病毒的能力,同时研究表明,鸡体提供了该病毒从非致病型向致病型转变的选择机制。  相似文献   
116.
Difficulty in airway management during anesthesia was noted in a 10-year-old, castrated, male Pekingese dog and a 13-year-old male French Bulldog. They showed strong resistance during tracheal tube insertion through the subglottic lumen. Therefore, the airway was secured by using a small endotracheal tube or supraglottic airway device. Computed tomography scan revealed a markedly narrower vertical dimension of the cricoid cartilage compared to that seen in common brachycephalic breeds. Posterior glottis was relatively more accessible for translaryngeal intubation in the present cases. Our findings showed that brachycephalic airway syndrome may be associated with narrow cricoid cartilage. To the best of our knowledge, this is the first clinical case report of airway management during anesthesia in dogs with narrow cricoid cartilage.  相似文献   
117.
118.
To clarify a postprandial glucose suppression effect of diacylated anthocyanin with alpha-glucosidase (AGH) inhibitory activity, a single oral administration study of it in male 8-week-old Sprague-Dawley rats was performed. The diacylated anthocyanin used in this study was peonidin 3-O-[2-O-(6-O-E-feruloyl-beta-D-glucopyranosyl)-6-O-E-caffeoyl-beta-D-glucopyranoside]-5-O-beta-D-glucopyranoside isolated from storage roots of the purple sweet potato (Ipomoea batatas cv. Ayamurasaki), which showed a potent maltase inhibitory activity with an IC(50) value of 200 microM preferable to sucrase inhibition. When the diacylated anthocyanin (100 mg/kg) was administered following maltose (2 g/kg), a maximal blood glucose level (BGL) at 30 min was significantly decreased by 16.5% (P < 0.01) compared to vehicle. A minimum 10 mg/kg dose of the anthocyanin was necessary for the suppression of glycemic rise, and the ED(20) (69 mg/kg) was estimated to be approximately 30-fold lower than that of the therapeutic drug acarbose (ED(20) = 2.2 mg/kg). A reduction of serum insulin secretion was also observed corresponding to the decrease in BGL. No significant change in BGL was observed when sucrose or glucose was ingested, suggesting that the anti-hyperglycemic effect of the anthocyanin was achieved by maltase inhibition, not by sucrase or glucose transport inhibition at the intestinal membrane.  相似文献   
119.
大豆Kunitz型胰蛋白抑制剂现已报告有6个电泳形态,Tia,Tib,Tic,Tia-s,Tib-f一一个最慢的电泳移动形态。Tia,Tib,Tic的活性已被报道。Tia和Tic有相似的活性,Tib的活性低于前两者。本文使用DEAE-cellulose层析化纯化了Tia和Tia-s蛋白和测定比较了这两个形态的活性。  相似文献   
120.
Pathogenicity of a fowl adenovirus (FAV), JM1/1 strain of serotype 1 derived from gizzard erosions of a broiler chicken, was examined to specific pathogen-free (SPF) chickens pre-treated with infectious bursal disease viruses (IBDVs) or cyclophosphamide (CY). Virulent IBDVs, classical type, were inoculated orally at 3 days of age of SPF chickens. CY was treated subcutaneously for 3 days after hatch. FAV was given orally at 30 days of age. At 40 days of age, all chickens were bled and autopsied for serology and gross observation. Gizzard lesions were ranked by the scores depending on their severities. IBDV- or CY-treated chickens showed significantly higher gizzard lesion scores than non treated birds. There were no gross lesions in any other organs except for bursal atrophy. Serologically, antibody production against FAV was highly suppressed by IBDV infection or CY treatment.  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