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11.
Minimum alveolar concentration (MAC) of an inhalant is an indicator of its anesthetic potency. Individuals vary in their sensitivity to anesthetic agents as demonstrated by different individual MAC values. We hypothesized that individual animal sensitivity would be maintained with different inhalant anesthetics. As part of separate studies, six female DSH cats, aged 24 ± 2.5 (mean ± SD) months and weighing 3.5 ± 0.3 kg, were studied similarly on three separate occasions over a 12‐month period to determine the MAC of isoflurane (ISO), sevoflurane (SEVO), and desflurane (DES), respectively. In each study, chamber induction was followed by orotracheal intubation, and anesthesia was maintained via a nonrebreathing circuit. ECG, pulse oximetry, Doppler systolic blood pressure, end‐tidal gases, and esophageal temperature were monitored. End‐tidal gases were hand‐sampled from a catheter whose tip lay level with the distal end of the ET tube. Gases were analyzed by Raman spectrometry and, for each agent, the analyzer was calibrated with at least three gas standards. MAC was determined in triplicate using standard tail‐clamp technique. Data were analyzed by two‐way anova followed by Tukey's test and significant differences were found. Average MACs (%) for ISO, SEVO, and DES were 1.90 ± 0.18, 3.41 ± 0.65, and 10.27 ± 1.06, respectively. Body temperatures, Doppler systolic blood pressure, and SpO2 were recorded at the time of MAC determinations for ISO, SEVO, and DES were 38.3 ± 0.3, 38.6 ± 0.1, 38.3 ± 0.35 °C; 71 ± 8, 75 ± 16, 88 ± 12 mm Hg; 99 ± 1, 99 ± 1, 99 ± 1%, respectively. Both the anesthetic agent and the individual cat had significant effects on MAC (p = 0.0001 and 0.0185, respectively). MAC varied between individuals and cats were consistent in their order of sensitivity to inhalant anesthetics across the three agents. Within this group of cats, the relationship of individual MAC to the group MAC for each of the three inhalant agents was maintained. This suggests that any individual may be consistently more or less sensitive to a variety of inhalant agents.  相似文献   
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Soil degradation and water pollution are widespread land degradation problems in Southeast Asia. Policy makers are currently faced with the challenge of designing and implementing strategies to maintain soil fertility and avoid off-site effects. The aim of this study was to determine the effect of organic substrate amendments on soil properties, nutrient leaching and the growth of Ipomea aquatica in an acidic degraded soil from northern Vietnam. Plants were grown in an Acrisol in buckets under natural weather conditions for two months. The same amount of nutrients was applied either in a purely synthetic form (mineral fertilizers) or as two alternative organic substrates (three month old compost or vermicompost from buffalo dung) plus additional amounts of synthetic mineral nutrients to ensure the same quantity of NPK. The influence of these respective substrates on the soil's physical and chemical properties as well as plant growth was examined. Both compost and vermicompost led to an improvement in soil properties with an increase in the pH, soil organic matter and nutrient content, compared to soil fertilized with synthetic mineral products. The highest plant productivity was obtained with vermicompost and synthetic fertilizers, with no significant difference between these two treatments. Chemical fertilization, however, is the least effective practice based on the amount of nutrients leached from the soil (about 38% of N and 22% of K, compared to less than 10 and 5% of N and K with organic amendments). P leaching was not influenced by the fertilizer treatments. In conclusion, vermicompost does appear to be a relevant alternative to chemical fertilizers because it leads to similar enhancements in plant growth, at the same time as increasing soil quality and decreasing nutrient leaching.  相似文献   
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The tidal rhythmites in the Proterozoic Big Cottonwood Formation (Utah, United States), the Neoproterozoic Elatina Formation of the Flinders Range (southern Australia), and the Lower Pennsylvanian Pottsville Formation (Alabama, United States) and Mansfield Formation (Indiana, United States) indicate that the rate of retreat of the lunar orbit is dxi/dt approximately k2 sin(2delta) (where xi is the Earth-moon radius vector, k2 is the tidal Love number, and delta is the tidal lag angle) and that this rate has been approximately constant since the late Precambrian. When the contribution to tidal friction from the sun is taken into account, these data imply that the length of the terrestrial day 900 million years ago was approximately18 hours.  相似文献   
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Tramadol is a centrally acting analgesic with opioid and monoaminergic actions. Its clinical effects have been well characterized in humans, where it has been in use for many years, but little is known for veterinary species. This study evaluated the sedative, emetic, thiopental‐sparing and intraoperative respiratory and hemodynamic effects of tramadol in comparison to morphine for pre‐medication of dogs undergoing orthopedic surgery under halothane anesthesia. Sixteen adult, healthy, mixed breed dogs (8.0 ± 2.6 kg) were studied. Eight dogs were pre‐medicated with tramadol (1.0 mg kg‐1 IM) and the other eight with morphine (1.0 mg kg–1 IM). After 20 minutes, anesthesia was induced with thiopental and subsequently maintained with halothane in oxygen using a Bain system, with spontaneous respiration. Degree of sedation and occurrence of emesis were evaluated after pre‐anesthetic medication. Dose of thiopental necessary for tracheal intubation was compared between the two groups. Arterial blood gas analyzes were done before pre‐medication and at 60 minutes of anesthesia. Heart rate and noninvasive arterial blood pressure were recorded before pre‐medication and every 10 minutes during anesthesia. Observer was blinded of the treatment given for each dog. Tramadol produced no visible sedation and no vomiting, while morphine induced a moderate degree of sedation in all dogs and vomiting in 62% of them. Dogs pre‐medicated with tramadol required significantly more thiopental (17 ± 3.8 mg kg–1) for induction of anesthesia than those pre‐medicated with morphine (12 ± 1.8 mg kg–1). Pre‐medication with morphine was associated with significantly higher PaCO2 and lower pH at 60 minutes of anesthesia. The remaining respiratory parameters and the hemodynamic variables were similar between the two groups. In conclusion, dogs pre‐medicated with tramadol at 1 mg kg–1 IM do not become visibly sedated and require a greater amount of thiopental for induction of anesthesia than pre‐medication with morphine. As intraoperative respiratory function is better preserved with tramadol, it may be useful for pre‐medication of respiratory compromised patients.  相似文献   
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The main objectives of the present study were to determine the ultrastructural modifications occurring in the oocyte during late folliculogenesis and to estimate pre-antral follicle population in buffalo. Half the collected ovaries were fixed and prepared for optic microscopy; the antral follicles from the other ovaries were measured and individually punctured. The cumulus–oocyte complexes (COCs) were processed for transmission electron microscopy. The number of pre-antral follicles in buffalo ovaries was estimated at 19 819 structures. Cumulus–oocyte complexes derived from 1-mm antral follicle had an eccentrical nucleus and compact corona radiata , ooplasm vilosities were fully embedded in zona pellucida (ZP) and a well-defined junction could be observed. Mitochondria were predominantly round and well distributed in ooplasm, as were small lipid vacuoles. In COCs derived from 2-mm antral follicles, the initial formation of perivitelline space was observed. The nucleus was peripherally located and the number of pleomorphic mitochondria increased. Cortical granules were clustered at oocyte periphery and lipid vacuoles increased in number and size. In COCs derived from 6-mm antral follicles, the organelles were located mainly in the perinuclear region. Golgi complexes and smooth endoplasmic reticulum (SER) were more developed. Mitochondria migrated to the cortical region and lipid vacuoles migrated to the medullar region. In COCs derived from 10-mm antral follicles, the lipid vacuoles coalesced and occupied the medullar region of the oocyte, together with a well-developed SER. Mitochondria were pleomorphic and located at the oocyte periphery. In conclusion, the morphological differences described in this paper could be responsible for some functional differences observed in in vitro embryo production and follicular dynamics for buffalo, when compared with cattle.  相似文献   
17.

Background  

The cultivar Micro-Tom (MT) is regarded as a model system for tomato genetics due to its short life cycle and miniature size. However, efforts to improve tomato genetic transformation have led to protocols dependent on the costly hormone zeatin, combined with an excessive number of steps.  相似文献   
18.
Experiments on a constant-density two-dimensional hole system in a gallium arsenide quantum well revealed that the metallic behavior observed in the zero-magnetic-field temperature dependence of the resistivity depends on the symmetry of the confinement potential and the resulting spin splitting of the valence band.  相似文献   
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