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   86篇
  免费   2篇
林业   2篇
农学   6篇
  20篇
综合类   9篇
农作物   6篇
水产渔业   2篇
畜牧兽医   35篇
植物保护   8篇
  2022年   2篇
  2021年   6篇
  2020年   3篇
  2019年   1篇
  2018年   1篇
  2017年   1篇
  2015年   1篇
  2013年   5篇
  2012年   3篇
  2011年   4篇
  2010年   2篇
  2009年   1篇
  2008年   5篇
  2007年   1篇
  2006年   3篇
  2005年   3篇
  2004年   4篇
  2003年   6篇
  2002年   7篇
  2001年   3篇
  2000年   1篇
  1999年   1篇
  1998年   2篇
  1996年   4篇
  1994年   1篇
  1993年   1篇
  1992年   2篇
  1991年   4篇
  1990年   3篇
  1989年   1篇
  1985年   1篇
  1982年   1篇
  1970年   1篇
  1969年   1篇
  1958年   1篇
  1953年   1篇
排序方式: 共有88条查询结果,搜索用时 15 毫秒
1.
In the period December 1967 through April 1969 eight spontaneous cases of pseudorabies in Danish red foxes were demonstrated by virus isolation. One fox had been kept in captivity, the remaining seven were free-living. Five of the foxes were found dead, while three, presenting abnormal behaviour when encountered, had been killed.  相似文献   
2.
3.
A 3-year-old Thoroughbred gelding was examined because of clinical signs of pneumonia and shock. Mucous membrane petechiation and ventral edema were observed and considered to be a result of vasculitis. Epidermal necrosis developed on the distal portions of the limbs. The horse had a persistent high fever that was unresponsive to nonsteroidal anti-inflammatory treatment, and Staphylococcus aureus was isolated from a nasal swab specimen and 2 transtracheal wash fluid samples. Antimicrobial, anti-inflammatory, and supportive treatment resulted in clinical improvement. However, resolution of the pulmonary infection required long-term (42 days) antimicrobial administration. Staphylococcus aureus strains isolated from this horse were positive for the toxic shock syndrome toxin-1 gene and were shown to produce toxic shock syndrome toxin-1, the causative factor in toxic shock syndrome in humans. The horse's clinical signs were attributed to toxic shock syndrome secondary to pulmonary S. aureus infection.  相似文献   
4.
Effects of exogenous administration of porcine recombinant somatotropin (rpST) on protein gain and metabolic rate were measured in three genotypes (castrated males) of pigs (Pietrain, Duroc and a crossbreed between Dutch Yorkshire and Dutch Landrace). Six pigs of each genotype were assigned at approximately 60 kg to receive pST doses of either 0 (C) or 14 mg (T) administered i.m. twice weekly over 10 wk. Pigs were housed in individual metabolism cages at a room temperature of 20 to 22 degrees C and received feed at 2.6 times maintenance. Protein gain (N x 6.25) was measured over the final 6 wk of the 10-wk test period. For 2 wk in the test period (wk 2 and wk 5), six pigs of each treatment x genotype group were placed in a large respiration chamber and energy balances (in protein and fat) and metabolic rate were measured. Rate of weight gain measured over the final 6 wk of the experimental period increased by 105 g/d (13%) with rpST administration (P less than .01). Daily protein gain over 6 wk was increased by 48 g/animal with application of rpST (P less than .001). There was a genotype x treatment interaction (P less than .01) for protein gain. Daily protein gain in Durocs with pST treatment was increased (39%) more than in crossbreds (31%). Daily fat gain was decreased by 42 g/animal (P less than .001) by T. Daily heat production with rpST was increased by 12 kcal/kg.75, which is comparable to a 12% increase in the maintenance energy requirement.  相似文献   
5.
Three feeding experiments were conducted in open circuit balance respirometers, to determine the effect of dietary protein level on growth rate, feed utilization and energy metabolism of Clarias gariepinus (Burchell). The feeding level was 2% of the fresh body weight per day. Three energy levels, 8.4, 12.6 and 16.8 kJ calculated metabolizable energy (ME) per gram of feed, were used, while crude protein levels in the diets were 20, 25, 30, 35 and 40%.Growth rate, heat production, metabolizability (ME as percentage of gross energy intake) and protein gain were maximal at the intermediate energy level. Digested protein per gram of growth was lowest at this energy level (determined ME = 13 kJ/g). Growth rate, metabolizability and protein gain increased as protein intake increased. There was no effect of the different protein levels on heat production. The efficiency of protein gain (% of the digestible protein intake) was highest (45–49%) at the intermediate energy level. Efficiency of protein gain (% of digestible intake) decreased slightly when protein intake increased. ME intake per gram of growth was minimal at the 8.4 kJ energy level and decreased at higher protein intake levels.At the highest energy level, growth rate was reduced compared to the intermediate energy level, but efficiency of energy gain, retention of fat and energy were highest. Much of the dietary fat was deposited as lipid reserves. After 4 weeks the growth rate, digestibility, metabolizability, and efficiency of protein- and energy gain (% of digestible or metabolizable intake respectively) were strongly reduced at this energy level.  相似文献   
6.
Effects of recombinant porcine somatotropin (rpST) on metabolic rate were studied in two trials with 24 crossbred barrows (Yorkshire x Landrace) in each. The barrows weighed about 80 kg (SE within trials 2.2 kg) at the start of the measurements and in each trial 12 pigs received 4 mg of rpST and 12 received a placebo. The diet contained 2.57 Mcal NE/kg and 20% CP (about 1% lysine). Animals were fed approximately 2.8 times maintenance (280 kcal ME.kg-.75.d-1). Heat production (gaseous exchange of CO2 and O2) and activity were measured continuously. Heat production associated with activity was calculated from the regression of heat production on activity. Animals treated with rpST exceeded controls in rate of gain by 252 g/d (P less than .001) and in metabolic rate by 14.5 kcal.kg-.75.d-1 (P less than .01). The rpST treatment increased rectal (+ .2 degrees C) and surface (+ .8 degrees C) temperatures. Activity-related heat production in treated pigs was increased, but this was only partly related to the increase in metabolic rate with rpST. The daily patterns of total and activity-related heat production were similar between pigs in both experimental treatments.  相似文献   
7.
Axonal regeneration in the adult central nervous system (CNS) is limited by two proteins in myelin, Nogo and myelin-associated glycoprotein (MAG). The receptor for Nogo (NgR) has been identified as an axonal glycosyl-phosphatidyl-inositol (GPI)-anchored protein, whereas the MAG receptor has remained elusive. Here, we show that MAG binds directly, with high affinity, to NgR. Cleavage of GPI-linked proteins from axons protects growth cones from MAG-induced collapse, and dominant-negative NgR eliminates MAG inhibition of neurite outgrowth. MAG-resistant embryonic neurons are rendered MAG-sensitive by expression of NgR. MAG and Nogo-66 activate NgR independently and serve as redundant NgR ligands that may limit axonal regeneration after CNS injury.  相似文献   
8.
The structure-activity relationships of synthetic caffeic acid amide and ester analogues as potential antioxidants and free radical scavengers have been investigated. The 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) scavenging activity of the test compounds was N-trans-caffeoyl-L-cysteine methyl ester (5) > N-trans-caffeoyldopamine (4) > N-trans-caffeoyltyramine (3) > N-trans-caffeoyl-beta-phenethylamine (2) > Trolox C (8) > caffeic acid phenethyl ester (1) > caffeic acid (6) > ferulic acid (7). This established that the radical scavenging activity of the compounds increased with increasing numbers of hydroxyl groups or catechol moieties and also with the presence of other hydrogen-donating groups (-NH, -SH). The antioxidative activity of the compounds was also investigated in an emulsified linoleic acid oxidation system accelerated by 2,2'-azobis(2-amidinopropane) dihydrochloride. The order was 1 > 2 > 4 > 3 > or = 5 > 6 > 8 > 7. Therefore, in the emulsion system, the antioxidative activity of the test compounds depends not only on the hydroxyl groups or catechol rings but also on the partition coefficient (log P) or hydrophobicity of the compounds. This supports the concept that hydrophobic antioxidants tend to exhibit better antioxidative activity in an emulsion system.  相似文献   
9.
Abstract

Extract

An infectious epididymitis of rams caused by Brucella ovis (Buddie, 1956 Buddle, M. B. 1956. J. Hygiene, 54: 351351.  [Google Scholar]) infection, first described in Australia (Simmons and Boyes, 1953 Simmons, C. G. and Hall, W. J. K. 1953. Aust.vet.J., 29: 3333. [Crossref] [Google Scholar]) and New Zealand (Buddie and Boyes, 1953 Buddle, M. B. and Boyes, B. W. 1953. Aust.vet. J., 29: 145145. [Crossref] [Google Scholar]) was recognized subsequently in Czechoslovakia (Gdovin et al, 1955 Gdovin, T., Hrudka, F., Chladecky, E. and Koppel, Z. 1955. Shorn, ces. Akad. zemedelsk Ved., 28: 617617.  [Google Scholar]), the United States (McGowan and Shultz, 1956 McGowan, B. and Shultz, G. 1956. Cornel Vet., 46: 277277.  [Google Scholar]), South Africa (Van Rensburg et al, 1958 Van Rensburg, S. W. J., Van Heerden, K. M., Le Roux, D. J. and Snyders, A. J. 1958. J.S.Afr. vet. med. Ass., 29: 223223.  [Google Scholar]), Rumania (Tudoriu, et al, 1958 Tudoriu, C. D., Andrei, M., Draghici, D. and Moldoveanu, P. 1958. Anu. Inst. Pat.Igien. anim. Bucaresti, 8: 55.  [Google Scholar]), and South America (Dr Justo Zomara B, 1961, pers. comm.). As the infection can affect ram fertility and, further, can be responsible for abortion in ewes and perinatal mortality in lambs, attention has been directed to the development, evaluation, and application of control measures in a number of important sheep-raising countries.  相似文献   
10.
Rift Valley fever virus (Phlebovirus, Bunyaviridae) is an arbovirus causing intermittent epizootics and sporadic epidemics primarily in East Africa. Infection causes severe and often fatal illness in young sheep, goats and cattle. Domestic animals and humans can be contaminated by close contact with infectious tissues or through mosquito infectious bites. Rift Valley fever virus was historically restricted to sub-Saharan countries. The probability of Rift Valley fever emerging in virgin areas is likely to be increasing. Its geographical range has extended over the past years. As a recent example, autochthonous cases of Rift Valley fever were recorded in 2007–2008 in Mayotte in the Indian Ocean. It has been proposed that a single infected animal that enters a naive country is sufficient to initiate a major outbreak before Rift Valley fever virus would ever be detected. Unless vaccines are available and widely used to limit its expansion, Rift Valley fever will continue to be a critical issue for human and animal health in the region of the Indian Ocean.  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