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   35篇
  免费   4篇
农学   1篇
  1篇
综合类   10篇
农作物   2篇
水产渔业   5篇
畜牧兽医   17篇
园艺   2篇
植物保护   1篇
  2023年   2篇
  2021年   1篇
  2020年   4篇
  2019年   2篇
  2018年   2篇
  2017年   2篇
  2015年   2篇
  2014年   1篇
  2013年   2篇
  2011年   2篇
  2008年   3篇
  2007年   1篇
  2005年   2篇
  2003年   2篇
  2001年   3篇
  1998年   1篇
  1997年   2篇
  1983年   1篇
  1970年   2篇
  1967年   1篇
  1963年   1篇
排序方式: 共有39条查询结果,搜索用时 15 毫秒
1.
Primary pulmonary neoplasia is relatively uncommon in cats and generally has a poor prognosis. In this multicenter, retrospective study of 57 cats with pulmonary neoplasia, the most frequent presenting signs were anorexia/inappetence (39%) and cough (37%). The pulmonary tumors were considered to be incidental findings in 9% cats. In computed tomographic (CT) images, primary pulmonary tumors appeared as a pulmonary mass in 55 (96%) cats and as a disseminated pulmonary lesion without a defined mass in two (4%) cats. Most pulmonary tumors were in the caudal lobes, with 28 (49%) in the right caudal lobe and 17 (30%) in the left caudal lobe. CT features associated with pulmonary tumors included mass in contact with visceral pleura (96%), irregular margins (83%), well‐defined borders (79%), bronchial compression (74%), gas‐containing cavities (63%), foci of mineral attenuation (56%), and bronchial invasion (19%). The mean (range) maximal dimension of the pulmonary masses was 3.5 cm (1.1–11.5 cm). Additional foci of pulmonary disease compatible with metastasis were observed in 53% cats. Pleural fluid was evident in 30% cats and pulmonary thrombosis in 12% cats. The histologic diagnoses were 47 (82%) adenocarcinomas, six (11%) tumors of bronchial origin, three (5%) adenosquamous cell carcinomas, and one (2%) squamous cell carcinoma. In this series, adenocarcinoma was the predominant tumor type, but shared many features with less common tumor types. No associations were identified between tumor type and CT features. Prevalence of suspected intrapulmonary metastasis was higher than in previous radiographic studies of cats with lung tumors.  相似文献   
2.
3.
Fifty-four isolates of various fish-pathogenic and saprophytic fungi were characterized in terms of their susceptibility to three antibiotics (penicillin, streptomycin and oxolinic acid), three fungicides (malachite green, hydrogen peroxide and sodium chloride) and three disinfectants (an iodophore, sodium hypochlorite and a solution of peracetic acid and hydrogen peroxide). Aphanomyces invaderis, the fungus associated with the Asian fish disease epizootic ulcerative syndrome (EUS); other Aphanomyces isolates from the similar conditions redspot disease (RSD) and mycotic granulomatosis (MG); and the crayfish plague fungus, Aphanomyces astaci, were more sensitive to most of the chemical agents than the other fungi tested. Two compounds currently being considered for use in aquaculture, hydrogen peroxide and Proxitane 0510, are shown here to have some potential for fungicidal treatments and disinfection, respectively. The implications of this study with respect to the isolation, treatment and control of A. invaderis are discussed.  相似文献   
4.
Pathogenicity and cultural experiments described here provide futher evidence that a distinct species of Aphanomyces is responsible for much of the characteristic pathology of epizootic ulceration syndrome (EUS). Zoospores from 58 fungal isolates were injected intramuscularly in snakehead fish, Channa striata (Bloch). These fungi comprised: Aphanomyces strains isolated from EUS-affected fish; saprophytic Aphanomyces , Achlya and Saprolegnia spp. from infected waters; and further saprolegniaceous fungi involved in other diseases of aquatic animals. Only the Aphanomyces strains isolated from fish affected by EUS, Australian red spot disease (already considered synonymous with EUS) or mycotic granulomatosis described from Japan were able to grow invasively through the fish muscle and produce the distinctive EUS lesions. In contrast to Aphanomyces astaci Schikora, the EUS- Aphanomyces was shown to be unable to infect noble crayfish, Astacus astacus L. The snakehead-pathogenic strains were further distinguished from all the other fungi under comparison by their characteristic temperature-growth profile and inability to grow on certain selective fungal media.  相似文献   
5.
Despite the recent advances in single-molecule manipulation techniques, purely mechanical approaches cannot detect subtle conformational changes in the biologically important regime of weak forces. We developed a hybrid scheme combining force and fluorescence that allowed us to examine the effect of subpiconewton forces on the nanometer scale motion of the Holliday junction (HJ) at 100-hertz bandwidth. The HJ is an exquisitely sensitive force sensor whose force response is amplified with an increase in its arm lengths, demonstrating a lever-arm effect at the nanometer-length scale. Mechanical interrogation of the HJ in three different directions helped elucidate the structures of the transient species populated during its conformational changes. This method of mapping two-dimensional reaction landscapes at low forces is readily applicable to other nucleic acid systems and their interactions with proteins and enzymes.  相似文献   
6.
7.
The compressibilities of three lunar samples were studied at room temperature from 0 to 40 kilobars. The samples were a fine-grained vesicular crystalline rock (type A), a microbreccia (type C), and fines (type D). All samples were porous. The microbreccia and fines were quite compressible at all pressures; the compressibility of the crystalline rock was somewhat less, being 8.4 megabar(-1) at 1 atmosphere and 1.5 megabar(-1) at 35 kilobars. Some porosity appeared to remain in the samples at all pressures. Thus the pressure-volume data derived from these samples may be representative of porous surface and near-surface material in the vicinity of the Apollo 11 landing site but may not be representative of lunar material at depth.  相似文献   
8.
9.
Feline and primate immunodeficiency viruses (FIVs, SIVs, and HIV) are transmitted via direct contact (e.g. fighting, sexual contact, and mother–offspring transmission). This dynamic likely poses a behavioral barrier to cross-species transmission in the wild. Recently, several host intracellular anti-viral proteins that contribute to species-specificity of primate lentiviruses have been identified revealing adaptive mechanisms that further limit spread of lentiviruses between species. Consistent with these inter-species transmission barriers, phylogenetic evidence supports the prediction that FIV transmission is an exceedingly rare event between free-ranging cat species, though it has occurred occasionally in captive settings. Recently we documented that puma and bobcats in Southern California share an FIV strain, providing an opportunity to evaluate evolution of both viral strains and host intracellular restriction proteins. These studies are facilitated by the availability of the 2× cat genome sequence annotation. In addition, concurrent viral and host genetic analyses have been used to track patterns of migration of the host species and barriers to transmission of the virus within the African lion. These studies illustrate the utility of FIV as a model to discover the variables necessary for establishment and control of lentiviral infections in new species.  相似文献   
10.
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