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   1076篇
  免费   56篇
  国内免费   1篇
林业   29篇
农学   45篇
基础科学   3篇
  100篇
综合类   264篇
农作物   125篇
水产渔业   87篇
畜牧兽医   422篇
园艺   11篇
植物保护   47篇
  2023年   4篇
  2022年   15篇
  2021年   31篇
  2020年   11篇
  2019年   14篇
  2018年   21篇
  2017年   14篇
  2016年   27篇
  2015年   17篇
  2014年   29篇
  2013年   51篇
  2012年   69篇
  2011年   73篇
  2010年   40篇
  2009年   41篇
  2008年   83篇
  2007年   86篇
  2006年   88篇
  2005年   70篇
  2004年   49篇
  2003年   47篇
  2002年   49篇
  2001年   38篇
  2000年   27篇
  1999年   14篇
  1998年   8篇
  1997年   11篇
  1996年   3篇
  1995年   5篇
  1994年   5篇
  1993年   7篇
  1992年   7篇
  1990年   9篇
  1989年   3篇
  1988年   4篇
  1987年   4篇
  1986年   6篇
  1985年   8篇
  1984年   5篇
  1983年   6篇
  1980年   3篇
  1978年   4篇
  1977年   2篇
  1976年   2篇
  1975年   3篇
  1974年   3篇
  1973年   4篇
  1971年   2篇
  1970年   3篇
  1969年   2篇
排序方式: 共有1133条查询结果,搜索用时 0 毫秒
121.
122.
123.
124.
125.
An 8-year-old female African wild dog (Lycaon pictus) from a zoo in Gyeonggi province, Republic of Korea presented with a 3.0 x 2.0 x 2.5 cm in size, smooth-surfaced, solitary pedunculated mass protruding into the uterine lumen. Microscopically, the mass was covered with epithelium, contained endometrial gland tissue, and was dilated in the vascularised stroma. Within the mass, there was extensive diffuse haemorrhage with several blood vessels apparently plugged with fibrin. At the base of the mass, the spaces lined with epithelium near the attachment of the stalk were interpreted to be glandular structures. There were segments of cuboidal epithelium found on the surface of the mass, which was similar to the lining the uterus. A diagnosis of an endometrial polyp was made based on the gross and histology findings. This is the first case report of a spontaneous endometrial polyp in an African wild dog.  相似文献   
126.
127.
128.
129.
Supercritical fluid (SCF) impregnation is a promising preservative treatment method for wood. In order to commercialize the sub- and supercritical CO2 biocide treatment, better understanding of the fluid phase and its effect on treatment results have to be demonstrated and developed. Preservative treatability under super- and subcritical fluid conditions was evaluated using radiata pine sapwood, and treating characteristics in relation to different fluid phases and treatability were discussed. Various treatment conditions resulted in varying biocide retentions and distributions. Higher pressure conditions enhanced biocide retentions resulting from increasing biocide input in the applied saturation method. Subcritical CO2 condition produced higher biocide retentions and little retention gradients from face to core. Subcritical CO2 treatment has a couple of benefits such as investment costs and energy consumption compared with supercritical CO2.  相似文献   
130.
Rotaviruses are important human and animal pathogens with high impact on public health and livestock industry. There is little evidence about the cross-species pathogenicity and extra-intestinal infections of animal and human reassortant rotaviruses, particularly based on all 11 genotyping data. In this study, the bovine triple reassortant KJ56-1 strain harboring two bovine-like genome segments, eight porcine-like genome segments, and one human-like genome segment was used to evaluate the cross-species pathogenicity in its parent species, calves and piglets, and to determine its abilities of causing viremia and extra-intestinal tropisms in piglets. The KJ56-1 strain isolated from a calf diarrhea fecal sample replicated without causing diarrhea and severe intestinal pathology in calves. However, piglets inoculated with this strain showed persistent severe diarrhea and marked intestinal pathology. By SYBR Green real-time RT-PCR, viral RNA was detected in the sera, mesenteric lymph node, lung, liver, choroid plexus, and cerebrospinal fluid in the experimental piglets. An immunofluorescence assay confirmed viral replication in these extra-intestinal organs and tissues. These results indicated that the bovine triple reassortant KJ56-1 strain was virulent to piglets but not to calves. Our data also demonstrated that the reassortant rotaviruses had the ability to spread to the bloodstream from the gut, enter and amplify in the mesenteric lymph node, and disseminate to the extra-intestinal organs and tissues.  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