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REASONS FOR PERFORMING STUDY: The risk of fatality is greater in jump than in flat racing in Victoria, Australia. This is the first study to identify risk factors specific to jump starts in Victoria. OBJECTIVE: To identify risk factors for fatality of Thoroughbred racehorses in jump starts on all racecourses in Victoria, Australia between 1989 and 2004. METHODS: Fatalities comprised all horses that died during or immediately after a jump (hurdle or steeplechase) race or official jump trial and all horses that were subjected to euthanasia within 24 h of an event in which an injury was sustained. The retrospective study involved 191 case starts and 2324 control starts. Univariable and multivariable backward stepwise logistic regression was used to identify risk factors for fatality at any one start. A multiple level model was used with racecourse included as a random effect. RESULTS: In the final multivariable model, the duration of the racing career of the horse, the number of flat, hurdle and steeple starts accumulated in the 60 days prior to the case or control start, the number of flat and jump starts accumulated over the racing career, if the horse had had a start between 1 and 14 days prior to the case or control start, the type of jump race (hurdle or steeple), the calendar year of the start and the location of the racecourse were associated with fatality. CONCLUSIONS: The findings highlight the need to investigate further the differences between hurdle and steeplechase events and the adverse effect of prolonged prior flat racing careers on the risk of fatality in jump starts. POTENTIAL RELEVANCE: This is the first study to examine risk factors for fatality in jump starts in Victoria. The results should shape the development of interventions to reduce the risk in jump starts in the future.  相似文献   
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Three groups of horses and ponies (N = 13, 13 and 12) were treated with ivermectin paste (0.2 mg/kg p.o.), avermectin B1 solution (0.2 mg/kg p.o.), or fenbendazole suspension (10 mg/kg via nasogastric tube). The avermectin B1 was a 1% solution in a propylene glycolglycerol formal base. Faecal strongyle egg counts were performed before, and 14, 28, 42, 56 and 70 d, after treatment. Full-thickness skin biopsies from the neck, pectoral and umbilical regions were examined for Onchocera microfilaria before treatment, and again 14 and 70 d later. Ivermectin therapy produced a significant (P less than 0.01) decrease in mean strongyle egg counts 14, 28, 42 and 56 d after treatment. Avermectin B1 therapy resulted in significant (P less than 0.01) decreases in mean strongyle egg counts 14, 28 and 42 d after treatment. All horses given ivermectin or avermectin B1 had zero strongyle egg counts 14 and 28 d after treatment. Fenbendazole failed to significantly decrease strongyle egg counts. Both ivermectin and avermectin B1 resulted in zero microfilaria counts in all horses 14 d after treatment. On day 70 the percentage decrease in microfilaria counts were 100% and 99.6% respectively. Fenbendazole failed to significantly decrease microfilaria counts. The oral administration of this formulation of avermectin B1 appeared to be highly efficacious against intestinal strongyles and Onchocera microfilaria. The duration of anti-strongyle activity was, however, significantly (P less than 0.01) shorter than that of ivermectin paste.  相似文献   
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OBJECTIVE: To identify the risk factors for premature retirement because of tendon injury in a Thoroughbred racehorse population. ANIMALS: 175 Thoroughbred racehorses (cases) at the Hong Kong Jockey Club that were retired from racing because of tendon injury between 1997 and 2004 and for which the last preretirement exercise was at a fast pace were each matched with 3 control horses that were randomly selected from all uninjured horses that had galloped on the same date as that last exercise episode. PROCEDURES: Training data for all horses were examined. Conditional logistic regression analyses were performed to identify risk factors for retirement from racing attributable to tendon injury. Two multivariable conditional logistic regression models were created; each contained 8 explanatory variables. RESULTS: Compared with control horses, case horses were older at the time of import, accumulated more race distance soon after import, were more likely to have had previous official veterinary or ultrasonographic examinations, raced fewer times during their career, and were in training for a longer period and had exercised at a reduced intensity during the 180-day period preceding the last fast-paced work date. CONCLUSIONS AND CLINICAL RELEVANCE: In addition to identification of risk factors for tendon injury among racing Thoroughbreds, results have suggested that resources focused on obtaining accurate training data may be misdirected in the absence of internationally agreed criteria for incident tendon injury among racehorses. Nevertheless, changes in training intensity and findings of previous clinical examinations could be used to identify horses at risk of tendon injury-associated retirement.  相似文献   
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The composition of the soil atmosphere is an indicator of biological processes, and soil CO2 gradients have been used to estimate CO2 efflux from the surface. Soil atmosphere samplers, constructed with gas-permeable materials, have been used to quantify soil CO2 concentrations. The type of material used can influence the perceived real-time concentrations of CO2 in the soil. Previous works have not directly compared different types of materials under the same conditions. The objective of this study was to determine the diffusion coefficient (D) and time of 95% equilibrium (teq) of CO2 through several materials, and to evaluate the effect of long-term soil burial (183 days) on diffusion characteristics. Materials tested included silicone, expanded Teflon (ePTFE), and ultra high molecular weight polyethylene (PE) tubing. The D of each material was determined using a closed-loop system consisting of a CO2-enriched (7800 ppm) chamber, a CO2 analyzer and an inner tube (experimental tubing) placed inside the chamber. Air was re-circulated through the inner tube, and as CO2 diffused from the chamber into the tubing, the analyzer recorded the increase in concentration. The silicone tubes had values of D ranging from 8.64 to 5.80×10−6 cm2 s−1 with corresponding teq between 3.9 and 9.7 h. Diffusion coefficients of the ePTFE (1.25×10−4 cm2 s−1) and PE (7.70×10−4 cm2 s−1) materials were 2 orders of magnitude greater, with teq<6 min. Exposure to the soil environment for 183 days did not visibly deteriorate the materials or significantly affect the D or teq values. Use of the ePTFE or PE materials, over the silicone materials, may allow for better characterization of dynamic CO2 concentrations in the soil based on the greater D and lesser teq values of these materials.  相似文献   
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A model reaction system was developed for generating pure thiosulfinates and propanethial-S-oxide (PTSO) using an isolated alliinase (EC 4.4.1.4) and isolated or synthetic alk(en)yl-L-cysteine sulfoxides (ACSO). Reaction yields ranged from 30 to 60% after 3 h at 21-23 degrees C, and organosulfur reaction products were extracted into CHCl3 to yield product preparations of controlled composition. A pure thiosulfinate or PTSO was derived from a single ACSO, and a preparation containing a mixture of four thiosulfinate species was derived from reaction mixtures employing binary ACSO substrate systems. Identities of homologous thiosulfinates and PTSO were confirmed by 1H NMR. This approach has the potential to be used as a preparative tool for yielding pure thiosulfinates and PTSO to facilitate the study of chemical and biological properties of this group of compounds or as a means to study the dynamics of organosulfur chemistry in preparations from Allium spp.  相似文献   
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Thiosulfinates (TSs) have been implicated as a principle source of the antiplatelet property of raw onion and garlic juice. The in vitro responses of human platelets to dosages of four TSs were measured using whole blood aggregometry and compared by regression analysis. Of the compounds evaluated, methyl methane-TS (MMTS), propyl propane-TS (PPTS), and 2-propenyl 2-propene-TS (allicin) are present in freshly cut Allium vegetables, whereas ethyl ethane-TS (EETS) has not been detected. All TSs were synthesized using a model reaction system. PPTS and allicin had the strongest antiplatelet activity at 0.4 mM, inhibiting aggregation by 90 and 89%, respectively. At the same concentration, EETS and MMTS were significantly weaker, inhibiting 74 and 26%, respectively. Combinations of TSs were not additive in their inhibition of aggregation, indicating that the antiplatelet potential of Allium extracts cannot be easily predicted by quantifying organosulfur components. EETS, PPTS, and allicin were significantly more potent platelet inhibitors than aspirin at nearly equivalent concentrations.  相似文献   
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