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   63篇
  免费   3篇
林业   3篇
  4篇
综合类   12篇
水产渔业   2篇
畜牧兽医   41篇
植物保护   4篇
  2020年   1篇
  2019年   3篇
  2017年   1篇
  2016年   2篇
  2015年   1篇
  2013年   14篇
  2012年   1篇
  2011年   2篇
  2009年   3篇
  2008年   1篇
  2007年   1篇
  2006年   2篇
  2004年   1篇
  2003年   1篇
  2002年   1篇
  2000年   1篇
  1999年   3篇
  1998年   2篇
  1997年   4篇
  1996年   2篇
  1994年   2篇
  1993年   2篇
  1991年   1篇
  1990年   2篇
  1989年   4篇
  1987年   3篇
  1982年   1篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1974年   1篇
排序方式: 共有66条查询结果,搜索用时 0 毫秒
1.
2.
Objective To evaluate standing, percutaneous, ultrasound-guided, transthoracic liver biopsy in mares, and transabdominal, laparoscopically-guided, liver biopsy under general anaesthesia in foals, as techniques for obtaining tissue for assessment of copper status. The techniques were evaluated with respect to ease of use and effect on the animal.
Procedure Twenty of 24 Thoroughbred mares and 21 of their foals were biopsied. The animals were part of a larger study of the effect of copper supplementation on copper status and the prevalence of developmental orthopaedic disease. Livers were also collected from unrelated horses and sampled to investigate the variability in the distribution of copper in liver tissue.
Result The biopsy technique caused no lasting effect on the mares, but there was an increased risk of viscus penetration associated with taking multiple biopsy cores. The use of ultrasonography to scan the target area for the liver identified four cases that were not appropriate candidates for liver biopsy, because of large intestine being located in the biopsy area. In the foals there were no serious postoperative adverse effects, nor was there any evidence of problems caused by the procedure when the abdomen was examined post-mortem at 5 months of age. In livers collected to investigate the variability of copper concentration, copper appeared to be relatively evenly distributed through the liver.
Conclusion Standing, percutaneous, ultrasound-guided, transthoracic liver biopsy in mares, and transabdominal, laparoscopically-guided, liver biopsy under general anaesthesia in foals are convenient procedures for obtaining liver tissue for assessing copper status in horses. The use of ultrasound to identify liver tissue is recommended, especially in older mares.  相似文献   
3.
Digital imaging of calcium indicator signals (fura-2 fluorescence) from single cardiac cells has revealed different subcellular patterns of cytoplasmic calcium ion concentration ([Ca2+]i) that are associated with different types of cellular appearance and behavior. In any population of enzymatically isolated rat heart cells, there are mechanically quiescent cells in which [Ca2+]i is spatially uniform, constant over time, and relatively low; spontaneously contracting cells, which have an increased [Ca2+]i, but in which the spatial uniformity of [Ca2+]i is interrupted periodically by spontaneous propagating waves of high [Ca2+]i; and cells that are hypercontracted (rounded up) and that have higher levels of [Ca2+]i than the other two types. The observed cellular and subcellular heterogeneity of [Ca2+]i in isolated cells indicates that experiments performed on suspensions of cells should be interpreted with caution. The spontaneous [Ca2+]i fluctuations previously observed without spatial resolution in multicellular preparations may actually be inhomogeneous at the subcellular level.  相似文献   
4.
Tick‐borne encephalitis virus (TBEV) is the aetiological agent of tick‐borne encephalitis (TBE), a potentially fatal central nervous system infection of humans. TBE is endemic in many areas of Europe and Asia; however, very scarce data on TBEV activity are available from Turkey. We aimed to identify TBEV exposure in healthy blood donors and the impact of TBEV in central nervous system infections in Central/Northern Anatolia. Two‐thousand four hundred and fifty four sera, collected from blood donors at Ankara, Konya, Eski?ehir and Zonguldak branches of the Turkish Red Crescent Middle Anatolia Regional Blood Center, were analysed for TBEV serosurveillance. Paired serum and cerebrospinal fluid samples from 108 patients with the diagnosis of aseptic meningitis/encephalitis of unknown aetiology were also evaluated to identify TBE and neuroborreliosis cases. Commercial enzyme‐linked immunosorbent assays and indirect immunofluorescence tests were employed for antibody detection. Forty‐seven donor samples (1.9%) were reactive for TBEV IgG. In 25 persons with IgG reactivity (53.1%), risk factors for tick‐borne infections were revealed. One sample from Zonguldak province (1/198; 0.5%) in the Black Sea region of Turkey was confirmed to possess neutralizing antibodies via plaque reduction neutralization test. TBEV IgM was detected in 9.2% (8/108) of the patients. IgM was accompanied by IgG reactivity in two persons where, in one, recent history of a tick bite was also identified. Intrathecal antibody production for TBEV could not be demonstrated. No evidence for Borrelia infections could be found. Confirmed exposure to TBEV and/or an antigenically similar tick‐borne flavivirus is documented for the first time in blood donors in Zonguldak in Northern Anatolia. Probable cases of TBE have also been identified from Central Anatolia. The epidemiology of TBEV activity in Turkey needs to be assessed and benefits of vaccination for general population, risk groups or travellers must be considered.  相似文献   
5.
While the Maillard reaction of free amino acids and proteins is a well-established process, no defined structures from the nonenzymatic browning of aminophospholipids in foodstuffs have been described so far. Phosphatidylethanolamine (PE)-linked glucosylamines (Schiff-PE), Amadori products (Amadori-PE), 5-hydroxymethylpyrrole-2-carbaldehydes (Pyrrole-PE), and carboxymethyl (CM-PE) as well as carboxyethyl (CE-PE) derivatives were detected and quantified by liquid chromatography- electrospray mass spectrometry (LC-(ESI)MS). Model incubations of soy-PE and D-glucose were employed to firmly establish the LC-(ESI)MS procedure. Analyses of spray-dried egg yolk powders and lecithin products derived therefrom show one-fourth of the native D-glucose content of egg yolk to be transformed to Amadori-PE, corresponding to a PE derivatization quota of 11-15.5 mol %. Schiff-PE and Pyrrole-PE were present only in low amounts, no CM-PE and CE-PE could be identified in any of the investigated samples. The high glycation rate of egg yolk PE will influence the emulsifying properties and perhaps even the oxidation resistance of the respective products.  相似文献   
6.
Mycoplasma-like organisms (MLOs) were detected in almost all examined trees of Alnus glutinosa and A. incana older than approximately 5 years. The minority of trees showed symptoms of decline while the others appeared healthy. MLOs were also found in A. glutinosa var. barbata, A. hirsuta, A. rubra, A. rugosa, A. subcordata, and A. tenuifolia.  相似文献   
7.
The purpose of this report is to recommend a code of practice to be followed by AI organisations and sire evaluation centres.The genetic merit of AI sires should be expressed as Breeding Values (BV) or as Relative Breeding Values (RBV). This value should be calculated for all traits which are considered for sire selection. The methods of estimation of the BV are discussed and it is suggested that where possible, methods based on the solution of properly constructed simultaneous equations (e.g. BLUP) should be used.For these new methods, a clearly defined reference base is required. It is recommended that where possible, this should be the average BV of the latest batch of bulls completing progeny test. If a fixed base is used, the average merit of bulls completing tests each year should be available.Besides good evaluation procedures and correction factors it is most important to ensure random use of the young bulls in many herds when they are doing their test inseminations in order to get unbiased progeny test figures. Only reliable figures should be published: the minimum requirements are suggested.A list of economically important traits is discussed. The traits are grouped under three headings: production traits, reproduction traits and management traits. Possible systematic environmental factors which have to be considered when estimating Breeding Values are listed in Appendix 1.The calculation of a selection index is recommended for use as a guide for proven bulls. The index can only be used in areas where the applied economic factors are appropriate, and so it is important to publish BV's for each trait separately.It is important that all test results should also be published in official bulletins. It is suggested, however, that the BV of important traits should not be published if the repeatability (r2) is less than 65%; for less important traits the repeatability of the estimated BV should be at least 35%. A scheme is suggested as to how the proofs can be presented.For international semen exchange the Relative Breeding Value is the recommended unit of evaluation. This value has the advantages that it is fairly independent of the mean levels and unit of measurement, and it is similar for all traits. A list of additional information which should be available is provided. Some important items are mentioned that should be taken into consideration when trials are planned, to compare different populations.  相似文献   
8.
Abstract

CASE HISTORY: A 5-year-old entire female Huntaway from a sheep and beef farm was one of four dogs that developed clinical signs including hypersalivation, depression, blindness and ataxia after the death of another dog. A 4-year-old female Huntaway farm dog from a second farm was observed to be sitting down more often than usual on the day after being fed part of a calf carcass that had been treated with an abamectin pour-on.

CLINICAL FINDINGS: The first dog was ataxic and depressed but did respond to sound. The second dog presented with an acute onset of blindness, mydriasis, absence of a menace response, hypersalivation, gait abnormalities (e.g. high stepping gait and ataxia), and depression. Other presenting signs included muscle tremors, dehydration and difficulty eating. No abnormalities were detected from routine haematology and biochemistry. Analysis of samples of plasma from both dogs revealed concentrations of abamectin of 0.149 mg/L and 0.260 mg/L for the first and second dogs, respectively. Buccal swabs taken from the first dog for DNA testing for the ABCB1 gene mutation, gave a negative result.

DIAGNOSIS: In addition to the presenting signs which suggested a toxicosis, both dogs had measurable concentrations of abamectin in plasma confirming exposure.

CLINICAL RELEVANCE: Farm dogs exposed to concentrated pour-on products containing abamectin have been poisoned and recover or die. The product labels do not carry any warnings as to the risk of poisoning to dogs. This paper discusses two incidents affecting six farm dogs, but the authors are aware of more toxicoses in farm dogs exposed to abamectin.  相似文献   
9.
AIM: To compare the efficacy of chelated versus inorganic forms of dietary Cu supplements, fed as a bolus, when challenged by a daily bolus of dietary Mo in cattle on a low-Cu diet.

METHODS: Forty non-lactating, Friesian dairy cows of adequate Cu status were assigned to four groups and fed a basal diet of baled silage containing 5.3 mg Cu and 0.4 mg Mo/kg DM. The experimental design was a factorial of two chemical forms of supplemental Cu and two levels of Mo intake, provided as pelleted grain supplements made from crushed barley/molasses plus Cu and Mo. The supplements contained 140 mg Cu/kg as Cu sulphate pentahydrate (CS), 140 mg Cu/kg as Cu glycinate (CG), CS plus 38 mg Mo/kg as sodium molybdate (CS+Mo), or CG plus 38 mg Mo/kg (CG+Mo). Commencing on Day 0, supplements were fed once daily (offered 1–1.2 kg/cow) and were completely consumed within 5–10 minutes, which constitutes a bolus type of administration. Liver samples were collected by biopsy at Days ?24, 13, 41 or 47, and 69 for Cu determinations.

RESULTS: The diets fed to the Cu+Mo groups were roughly equivalent to 25 mg Cu and 5.7 mg Mo/kg DM. Mean initial concentration of Cu in liver for all groups was 516 (SE 54) μmol Cu/kg fresh tissue. In cows supplemented with CS and CG, the final (Day 69) concentrations increased (p<0.01) to 939 (SE 166) and 853 (SE 163) μmol Cu/kg, respectively. These values were not different (p=0.72). For groups CS+Mo and CG+Mo, the final concentrations of 535 (SE 122) and 453 (SE 102) μmol Cu/kg were not different from initial values or from each other (p>0.25). The rate of accumulation of Cu in liver following bolus Cu and Mo intake was highly variable but was not affected by initial concentration of Cu in liver (p>0.9) or by the form of Cu (p>0.6). Mean rates of accumulation of Cu in liver were 4.0 (SD 3.8) and 0.65 (SD 2.0) μmol Cu/kg fresh tissue/day for the Cu-only treatments and the Cu+Mo treatments, respectively.

CONCLUSIONS: When fed together as a bolus, high Mo intake negated the effect of supplemental Cu but it did not reduce liver Cu stores. There was no difference in the reaction of dietary Mo with chelated Cu (as glycinate) versus inorganic Cu (as sulphate) dietary supplements.  相似文献   
10.
CASE HISTORY: A routine ultrasonographic examination for pregnancy diagnosis in a 3-year-old ewe revealed a normal embryo located in the uterine cavity and an abnormal mass located in the abdomen. At the time of examination, the ewe was 4.5?months pregnant, but 10?months previously she had undergone a caesarean section due to dystocia.

CLINICAL FINDINGS: The abnormal mass (12?cm × 8?cm) was located outside the uterine cavity; it was anechoic at the periphery, and in the centre there was an echogenic embryo-like structure. Exploratory laparotomy was performed, which revealed an ectopic pregnancy through the caesarean scar.

TREATMENT: The ectopic foetus was excised and the caesarean scar was repaired. The ewe made a complete recovery and the intrauterine pregnancy was completed to full-term, resulting in the birth of a healthy female lamb 35?days after the removal of the ectopic foetus.

CLINICAL RELEVANCE: Ectopic pregnancies have previously been described in ewes. As far as the authors are aware, this is the first report of an ectopic pregnancy through a caesarean scar in sheep or any other farm animal species.  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