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   200篇
  免费   5篇
  国内免费   2篇
林业   15篇
农学   2篇
  26篇
综合类   9篇
农作物   2篇
水产渔业   19篇
畜牧兽医   98篇
园艺   3篇
植物保护   33篇
  2024年   1篇
  2022年   7篇
  2021年   16篇
  2019年   1篇
  2018年   2篇
  2017年   7篇
  2016年   4篇
  2015年   7篇
  2014年   10篇
  2013年   9篇
  2012年   12篇
  2011年   14篇
  2010年   6篇
  2009年   4篇
  2008年   12篇
  2007年   14篇
  2006年   9篇
  2005年   9篇
  2004年   22篇
  2003年   12篇
  2002年   16篇
  2001年   6篇
  2000年   4篇
  1998年   1篇
  1996年   1篇
  1995年   1篇
排序方式: 共有207条查询结果,搜索用时 46 毫秒
61.
A male Holstein-Friesian calf was born with multiple, cauliflower-like, pale pink cutaneous masses on the head and limbs. On histopathological examination, the cutaneous masses were diagnosed as congenital cutaneous fibropapillomatosis. Those lesions involved focal proliferation of sebaceous gland in the dermis. There were no histological findings to suggest bovine papillomavirus infection, such as the presence of intranuclear inclusion bodies, large keratohyalin granules, and koilocytosis. Furthermore, papillomaviral antigens and DNA were not detected by immunohistochemistry and polymerase chain reaction, respectively. These results suggested that there was no association between these cutaneous lesions and bovine papillomavirus infection, and the lesions were considered as harmartomatous changes.  相似文献   
62.
We observed the effects of a commercial microbiological additive (MA) on the beef manure composting process and investigated the changes in its physical and chemical components and microbial populations in the composting process. When beef manure compost was inoculated with the MA, its temperature rapidly increased at the beginning of the process, and after the first turning, the ammonia emission from the compost pile and nitrate production decreased quicker than that in the composting process without the MA. During the composting process, the manure inoculated with MA showed a larger numbers of mesophilic and thermophilic aerobes, and a smaller number of thermophilic anaerobes than in the process without the MA. These results suggested that mesophilic aerobes increased in number and metabolized ammonia by assimilation rather than nitrification to accelerate the temperature elevation in the composting process with the MA.  相似文献   
63.
64.
The therapeutic efficacy of atovaquone against Babesia gibsoni was examined in three dogs experimentally infected with B. gibsoni isolated from naturally infected dogs in Aomori Prefecture, Japan. Once parasitemia reached 10%, atovaquone was administered orally (30 mg/kg twice daily for 7 days). Within 2 days of atovaquone treatment, the parasite disappeared from blood smears without any clinical side effects. Anemia and thrombocytopenia were significantly improved in all the dogs. However, a polymerase chain reaction assay revealed that a B. gibsoni marker gene was intermittently present in peripheral blood after atovaquone therapy, indicating that the organism had not been eliminated, and parasites reappeared in blood smears 33 days after the last treatment. To investigate the change in sensitivity against atovaquone, an in vitro sensitivity test was performed using peripheral blood obtained from an untreated dog that was infected with the original parasite isolate, and from two of the experimentally infected and atovaquone-treated animals (blood was collected at the time of the post-treatment recurrence of the B. gibsoni infection). Atovaquone was added to the culture medium to final concentrations of 0.1, 1, 10, 100, and 1000 nM. For the untreated parasites, complete growth inhibition occurred at 1000 nM of atovaquone, whereas the recurrent parasites were inhibited by only 39.52 +/- 8.34% and 31.31 +/- 8.14% at this concentration after 48 h of incubation. Thus, the recurring parasites were less sensitive to atovaquone than the untreated originally isolated parasites.  相似文献   
65.
Stress interferes with reproduction, adversely influencing implantation and fetal growth, and sometimes even leading to abortion. Here, we attempted to evaluate the early gestational effects of uncomfortable sound on pregnant mice and their offspring. Ten-week-old pregnant Jcl:ICR mice were exposed to sound (100 dB, random frequency between 9-34 kHz) for 8 hours on the 3(rd), 5(th) and 7(th) gestational days (GD). The effects of general anesthesia were also investigated, with or without acoustic stress. All groups were examined on the 18(th) GD for fetal growth. Fetal weight, number of ossified sacrococcygeal vertebrae and placental weight were all significantly reduced (P<0.0001) when stress was induced on the 7(th) GD, but not on the 3(rd) or 5(th) GD. This intra-uterine growth retardation (IUGR) was significantly inhibited by general anesthesia (P<0.0001), although general anesthesia alone induced significant IUGR (P<0.0001) when compared with control mice. This suggests that acoustic exposure indirectly exerts an effect on fetal growth, possibly via a psycho-maternal pathway. We also found that analysis of the number of ossified sacrococcygeal vertebrae is the most sensitive tool for the study of IUGR.  相似文献   
66.
We determined nearly the complete sequences of the 16S ribosomal RNA gene (rDNA) for Japanese strains of R. solanacearum. The comparison of 1471 nucleotide positions separated the Japanese strains into two groups, group 1 with biovars 1, 2, 3 and 4 strains which belonged to race 1, and group 2 with biovar 2 strains corresponding to race 3. Group 1 strains all had identical sequences, and strains representing the four biovars within the group did not differ from each other. Group 2 strains had characteristic nucleotides which differed at seven positions from group 1 strains. Comparative analysis of Japanese and foreign strains based on 16S rDNA sequences showed that Japanese group 1 was closely related to Asian and Australian biovars 3, 4 and 5, and belonged to the known division 1. Japanese group 2 was homogeneous to Indonesian biovars 2 and N2 in subdivision 2b. Since the differences in the nucleotides corresponded to restriction sites for the AluI, RFLP analysis of PCR-amplified 16S rDNA efficiently differentiated not only Japanese group 1 from group 2, but also differentiated three types of foreign strains which differed in biovar and geographic origin. Received 26 July 1999/ Accepted in revised form 19 November 1999  相似文献   
67.
68.
The superior capability of cognitive experts largely depends on quick automatic processes. To reveal their neural bases, we used functional magnetic resonance imaging to study brain activity of professional and amateur players in a board game named shogi. We found two activations specific to professionals: one in the precuneus of the parietal lobe during perception of board patterns, and the other in the caudate nucleus of the basal ganglia during quick generation of the best next move. Activities at these two sites covaried in relevant tasks. These results suggest that the precuneus-caudate circuit implements the automatic, yet complicated, processes of board-pattern perception and next-move generation in board game experts.  相似文献   
69.
70.
Antioxidative activities of volatile extracts from six teas (one green tea, one oolong tea, one roasted green tea, and three black teas) were investigated using an aldehyde/carboxylic acid assay and a conjugated diene assay. The samples were tested at levels of 20, 50, 100, and 200 micrograms/mL of dichloromethane. The results obtained from the two assays were consistent. All extracts except roasted green tea exhibited dose-dependent inhibitory activity in the aldehyde/carboxylic acid assay. A volatile extract from green tea exhibited the most potent activity in both assays among the six extracts. It inhibited hexanal oxidation by almost 100% over 40 days at the level of 200 micrograms/mL. The extract from oolong tea inhibited hexanal oxidation by 50% in 15 days. In the case of the extract from roasted green tea, the lowest antioxidative activity was obtained at the level of 200 micrograms/mL, suggesting that the extract from roasted green tea contained some pro-oxidants. The extracts from the three black teas showed slight anti- or proactivities in both assays. The major volatile constituents of green tea and roasted green tea extracts, which exhibited significant antioxidative activities, were analyzed using gas chromatography-mass spectrometry. The major volatile chemicals with possible antioxidative activity identified were alkyl compounds with double bond(s), such as 3,7-dimethyl-1,6-octadien-3-ol (8.04 mg/kg), in the extract from green tea and heterocyclic compounds, such as furfural (7.67 mg/kg), in the extract from roasted green tea. Benzyl alcohol, which was proved to be an antioxidant, was identified both in a green tea extract (4.67 mg/kg) and in a roasted tea extract (1.35 mg/kg).  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