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   62篇
  免费   3篇
基础科学   1篇
  3篇
综合类   4篇
农作物   4篇
畜牧兽医   51篇
植物保护   2篇
  2023年   1篇
  2021年   1篇
  2020年   1篇
  2019年   1篇
  2018年   2篇
  2017年   1篇
  2016年   2篇
  2014年   1篇
  2013年   4篇
  2012年   1篇
  2011年   2篇
  2010年   2篇
  2009年   2篇
  2008年   4篇
  2007年   6篇
  2006年   3篇
  2005年   3篇
  2004年   1篇
  2002年   1篇
  1999年   5篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   3篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1985年   1篇
排序方式: 共有65条查询结果,搜索用时 31 毫秒
51.
An immunohistochemical study of 25 lesions from 7 dogs with disseminated aspergillosis (Aspergillus terreus) is presented. All had multiple fungal granulomas in many viscera, with centres of necrotic tissue and hyphal elements surrounded by a mixed infiltrate of predominantly mononuclear cells. Within these lesions, hyphae coated with immunoglobulin (IgG, IgM, IgA) and complement (C3, C4) were identified, together with peri-lesional mononuclear cells that reacted with antisera directed towards either IgG, IgM, IgA or a T lymphocyte marker (MUII). A conspicuous feature was the prominent hyphal fluorescence seen with IgA and C3 antisera. The IgA reagent also marked large numbers of mononuclear cells both around lesions and scattered throughout interstitial tissue, suggesting an abnormality of IgA production or regulation as a factor predisposing to this condition.  相似文献   
52.
The effects on white clover ( Trifolium repens ) of different combinations of the nematodes Meloidogyne trifoliophila , Helicotylenchus dihystera and Heterodera trifolii and nine stolon-infecting and three root-infecting fungi were studied in a glasshouse experiment. The presence of the fungus Phytophthora megasperma alone increased ( P  < 0·001) root-rot severity and reduced ( P  < 0·001) plant growth. Other species combinations, such as Phoma nebulosa and Alternaria alternata , interacted and increased root-rot severity. Combinations of P. megasperma with Pythium irregulare , and P. nebulosa with Phoma medicaginis or A. alternata , increased M. trifoliophila populations. Several other fungi ( P. irregulare , P. nebulosa , Colletotrichum coccodes , Macrophomina phaseolina , P. medicaginis and Phoma sp.) interacted with the nematode M. trifoliophila causing severe root-knot symptoms. The results indicated that fungi and nematodes interacted to cause root and stolon rot and reduced yields, and that poor persistence of white clover in pastures is likely to be a problem with a complex etiology.  相似文献   
53.
AIMS: To evaluate a multivalent leptospiral and clostridial vaccine for prevention of renal colonisation and urinary shedding in sheep, following experimental challenge with New Zealand strains of Leptospira borgpetersenii serovar Hardjo type Hardjobovis and L. interrogans serovar Pomona.

METHODS: Two separate but similarly designed studies were conducted. In both studies, Romney-cross lambs, aged 9–11 weeks, were randomly allocated to a vaccinated group and a control group. Vaccinated lambs each received two 1.5-mL S/C doses of a multivalent leptospiral and clostridial vaccine, 4 weeks apart, and animals in the control groups received the same dose of saline. Groups of 12 vaccinated and 12 control lambs were randomly selected in each study for challenge with serovars Hardjo or Pomona. Challenge was initiated 16 weeks following the second vaccination with three daily doses of live leptospires by intranasal and conjunctival routes. Following challenge, urine samples were collected weekly for 6 weeks, for dark field microscopy and leptospiral culture; 6 weeks after challenge the lambs were slaughtered and kidneys collected for leptospiral culture.

RESULTS: In lambs challenged with serovar Hardjo, 8/12 unvaccinated lambs had ≥1 urine or kidney sample that was positive for leptospires following culture, compared with 0/12 lambs in the vaccinated group (p=0.001). In lambs challenged with serovar Pomona, 9/12 unvaccinated lambs had ≥1 urine or kidney sample that was positive following culture, compared with 0/12 lambs in the vaccinated group (p<0.001). Prevention of renal colonisation and urinary shedding, expressed as the prevented fraction, was 100 (95% CI=61.7–100)% and 100 (95% CI=68.3–100)% against challenge with serovars Hardjo and Pomona, respectively, at 4 months after vaccination.

CONCLUSIONS AND CLINICAL RELEVANCE: Use of a multivalent leptospiral and clostridial vaccine demonstrated protection against challenge from New Zealand strains of serovars of Hardjo and Pomona 4 months after vaccination in lambs first vaccinated at 9–11 weeks of age. Further studies are required to assess the duration of immunity against challenge in sheep.  相似文献   

54.
Relatively molecular mass of GnRH antigens is small and hence needs to couple to a large carrier molecule to enhance its immunogenicity. This study investigated whether hepatitis B surface antigen S (HBsAg‐S) gene can be used as an effective carrier molecule for developing GnRH DNA immunocastration vaccine. Two copies of human GnRH gene were fused with HBsAg‐S gene for constructing a recombinant plasmid pVAX‐HBsAg‐S‐2GnRH that coded for 27 kDa target fusion protein. Ten male mice were divided into two equal groups, treatment and control. The vaccine (50 μg/mice) prepared in saline solution was injected into male mice at weeks 0, 1, 2, 4 and 7 of the experiment. Vaccine's efficacy was evaluated in terms of GnRH‐specific IgG antibody response, plasma testosterone levels, testicular weight and extent of the testicular tissue damage. The specific anti‐GnRH antibody titre in vaccinated animals was significantly higher than in controls in only 4th week of immunization (p < 0.05). In addition, vaccinated animals showed lower testicular weight than those of the controls (p < 0.05). Spermatogenesis in seminiferous tubules in vaccinated animals was suppressed. In conclusion, in this study, the engineered plasmid to be used as a GnRH DNA vaccine induced antibody response and suppressed spermatogenesis in mice. This suggests that HBsAg‐S gene can be an effective carrier molecule for developing GnRH DNA immunocastration vaccine when relatively molecular mass of the aimed antigens is small.  相似文献   
55.
56.
Luteolytic mechanisms have evolved in mammals to improve reproductive efficiency. The hormonal interactions that control the onset and progress of luteolysis are complex. They involve endocrine and paracrine signals that link the corpus luteum, uterus and posterior pituitary gland. Current concepts concerning these interactions will be examined in the five major domestic ungulate species commonly raised in Europe and North America (cattle, sheep, goats, pigs and horses). Some of these interactions are similar across species. All five depend on prostaglandin F secreted from the uterus, to induce luteolysis. Three hormones, progesterone, estradiol and oxytocin interact to regulate uterine secretion of PGF. Oxytocin is an acute stimulus for uterine PGF secretion. Progesterone and estradiol interact to regulate uterine secretary responsiveness to oxytocin. Precisely how these hormones interact varies across species.  相似文献   
57.
A 2-month-old intact female Rottweiler was presented for investigation of coughing and respiratory distress 9 d after an exploratory laparotomy for intestinal foreign body removal. Tracheal stenosis was suspected by radiography and confirmed with computed tomography (CT) and tracheoscopy. After 1 wk of medical management, clinical signs had resolved and the severity of the tracheal narrowing was markedly improved, as confirmed by radiography and tracheoscopy. Tracheal stenosis is a considerable complication of endotracheal intubation in veterinary medicine and may be medically managed, depending on the severity of the tracheal injury.Key clinical message:To our knowledge, this is the first clinical case report of tracheal stenosis resulting from endotracheal intubation in a dog and its resolution after medical management.  相似文献   
58.
Cerebral microbleeds in people are small foci of hemosiderin-containing macrophages in normal brain parenchyma. They are the remnant of previous hemorrhage and occur with greater frequency in older individuals. Our purpose was to describe the magnetic resonance (MR) appearance of cerebral microbleeds in four dogs. These lesions appeared as round, hypointense foci measuring ≤4 mm on T2*-gradient-recalled echo images. They were less conspicuous or absent on T2-weighting, being iso- or hypointense, and uniformly invisible on T1-weighted images. No contrast enhancement was seen in any of the cerebral microbleeds. Necropsy-derived histopathologic analysis of one brain confirmed these lesions to be chronic cerebrocortical infarcts containing hemosiderin. The MR changes seen in dogs were analogous to what has been described in people and will be helpful in distinguishing cerebral microbleeds from other brain lesions.  相似文献   
59.
The effects of feeding different levels of forages and concentrate, in a discontinuous feeding pattern, on the efficiency of feed utilisation and rumen function were studied using rumen fistulated sheep. Experiment 1 was a 4 × 4 latin square design to determine the whole tract digestibility and rumen characteristics of diets comprising 15% (C15), 25% (C25), 35% (C35) and 45% (C45) concentrate (energy-dense dairy pellets) with the rest of the diet being a combination of fresh short rotation ryegrass (Lolium mutiforum) and conserved (lucerne hay and maize silage) forages. In Experiment 2, the rumen degradation characteristics of feed ingredients were determined using the nylon bag technique. Daily dry matter intake (either expressed as g/kg LW or g/kg W 0.75) was 10% lower (p = 0.03) for the C15 diet compared with C25, C35 and C45 diets. The apparent in vivo digestibility of dry matter (DM) for C15 diet was 4% higher (p = 0.04) than the C35 and C45 diets which may be attributed to the high quality of the forage (ryegrass) used.Fibre digestibility decreased as proportion of concentrate in the diet increased. However, this was unlikely due to changes in the rumen fermentation pattern, as neither pH (6.1 ± 0.23) nor ammonia concentration (24.4 ± 6 mg/dl), were different (p > 0.05) among diets. Instead, the lower fibre digestion was most likely the result of different type and proportion of fibre among diets, as total rumen degradability and rate of fibre degradation in the rumen were higher (p = 0.001) for ryegrass than for other feedstuffs. There was no significant difference in total nitrogen balance and urinary allantoin excretion among diets, which indicated similar total microbial protein synthesis (MPS). The asynchrony observed, for N and energy availability in the rumen for different diets using Sinclair et al. [Sinclair, L.A., Garnsworthy, P.C., Newbold, J.R., Buttery, P.J., 1993. Effect of synchronizing the rate of dietary energy and nitrogen release on rumen fermentation and microbial protein synthesis in sheep. J. Agric. Sci. 120, 251–263] equation, was due to the feeding pattern used in this study leading to excess of N in relation to total organic matter digested in the rumen. In conclusion, feeding concentrates in the diets as PMR with conserved forages in a discontinuous feeding pattern may be valuable to develop feeding strategies in a pasture based system for high producing dairy cows without affecting the rumen system.  相似文献   
60.
OBJECTIVE: To compare the ease of placement and ventilatory parameters of a laryngeal mask airway (LMA) with an endotracheal tube (ETT) in anesthetized swine during positive-pressure ventilation (PPV). STUDY DESIGN: Prospective, randomized, experimental trial. ANIMALS: Nine young domestic swine, weighing between 40 and 49 kg (mean 45.1 kg), being used for a separate terminal surgical study. METHODS: The pigs were immobilized with tiletamine/zolazepam, 2.7-3.6 mg kg(-1), intramuscularly, followed by isoflurane in oxygen delivered by facemask. The lungs were mechanically ventilated through an ETT or an LMA, in random order, during the anesthetic period. Positive-pressure ventilation was adjusted to maintain end-tidal CO2 (Pe'CO2) between 35 and 45 mmHg, with peak inspiratory pressure (P(insp)) of 15-23 cmH2O. Buprenorphine, 0.3 mg intramuscularly, was given to each pig after instrumentation. Isoflurane vaporizer settings were adjusted to maintain a surgical plane of anesthesia. Respiratory rate (RR), tidal volume (V(T)), minute volume (V(E)), and Pe'CO2 were measured and recorded at 5-minute intervals. After the collection of 1 hour of data, the alternate airway was placed. Swine were given at least 30 minutes to stabilize and another hour of data were recorded. At the time of airway placement, the ease of placement was assessed based on time and the number of personnel required. Data were analyzed using paired Student's t-test or Wilcoxon signed rank test where appropriate. RESULTS: Laryngeal mask airways were significantly easier to place than ETT. Values for V(T) and V(E) were not significantly different between treatments. Peak inspiratory pressures were higher in ETT-ventilated swine. CONCLUSIONS AND CLINICAL RELEVANCE: An LMA may be used as an alternative to an ETT in mechanically-ventilated anesthetized swine. Use of an LMA may reduce time and personnel required for placement of an airway.  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